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OrthoEngine User's Guide.book

1. Action Keyboard Key Mouse Switch between the pointer ESC and the stereo cursor Recenter at the stereo R F1 cursor Snap to Ground G F2 Remove parallax F F3 Recenter and remove F4 parallax Zoom In PAGE UP CTRL click Zoom Out PAGE DOWN CTRL right click Move Image to the left J Move Image to the right K Move Image up l 94 PCI Geomatics Extracting Vector Points from a Digital Elevation Model Table 3 Shortcuts for the 3 D viewer Action Keyboard Key Mouse Move Image down M Move stereo cursor to a Z rotate the wheel higher elevation button forward Move stereo cursor to a X rotate the wheel lower elevation button backward Move the stereo cursor to RIGHT ARROW the right Move the stereo cursor to LEFT ARROW the left Move the stereo cursor UP ARROW upwards Move the stereo cursor DOWN ARROW downwards Accept ENTER or double click SPACE Cancel BACKSPACE right click Undo U F5 New Point P F6 New Line L F7 New Polygon O F8 Snap to Vertex V F9 Snap to Line C F10 Insert Vertex INSERT F11 Delete Vertex D F12 Delete Line DELETE Move B Extracting Vector Points from a Digital Elevation Model You can extract vector points from a digital elevation model DEM raster and then save the vector points to a vector layer You can export the vector points to any supported vector format or dis
2. sees ene neen nennen nene enhn ener ine nennen innen nennen 118 Regenerating Bur doc J 118 Mosaicking Digital Elevation Models ssessseneeen eene enne erret enne e nnns s et enr sen nnns nennen nene nennen e nennen nennen nnne 119 Chapter 10 ADDITIONAL FEATURES Understanding thi Enhancements erinnere ied ecd tice eene ede gente ino 121 Using Zoom Rel oad Andi Pan s iui iit a acc conet om a do t ere os 122 Loading Vectots Over an Image 3e Eee a she E 122 Changing the Color of a Vector Layer annriki i 123 CurSOr Controlo e naed Tees aii A A eita A E EEEE EA aa 123 Changing Image Color Channels sigante idei aeta at iae ddr a 123 Sele ting Image Cha Mes ees 123 REMOVING IMAGES ind 124 Re connecting Offline Mage ii ida 124 Renaming MAGES ss ioi alla eat eames 124 Synchronizing the Images a H 9 125 Replacing image Pixel Valles 4 5 sass 2 enti oes A ie a 125 Converting the DEM Datum A a cente ined one ide 126 Rejoining StitchiNg Image THES ERR 126 Setting the Automatic Backup A A a ae pepe pute saec eg eee greet 127 Setting Default Ground Control Point Elevation Units ssssesseseeeneennnenen rre 127 Setting a Default Ground Control Point Eleva
3. OrthoEngine User s Guide 93 Chapter 7 Editing Features in 3 D Stereo To save a layer 1 Click Save Layer 2 Select a location 3 Type the name for the layer in the File name box and select a format from the Files of Type list 4 Click Save 5 Under Savable Vector Layers select the layer that you want to save 6 Inthe Description box type a description that will help you identify the contents of the layer 7 Inthe Name box type a label for layer 8 Click Save or Save amp Close To replace an existing layer 1 Click Save Layer 2 Select the file and click Save 3 Under Database Vector Segments select the layer that you want to replace 4 Under Savable Vector Layers click the layer that you want to save 5 Click Save or Save amp Close Quote If you selected a layer under Database Vector Segments but you do not want to replace the layer click Create New Segment and type a new description in the Description box and label in the Name box Deleting a Layer You can remove a layer from the Vector Layer Information table without deleting it from the disk To remove the layer from the table 1 Select the layer that you want to remove 2 Click Delete Layer 3 Click Yes The layer will disappear from the table and from the 3 D viewer Using Shortcuts in the 3 D Viewer You can use these shortcuts in any combination Table 3 Shortcuts for the 3 D viewer
4. 3 In the Name box type a name that you want to appear on the title bar of the OrthoEngine window 4 In the Description box type a description of the project that will help you to identify its contents 5 Under Math Modelling Method click Aerial Photography 6 In the Camera Type list select the camera type corresponding to the images that you are using in your project Click Standard Aerial Camera when the images are scanned from film or paper prints These often measure 9 inches by 9 inches in size and usually contain calibration fiducial marks Normally a camera calibration report is supplied with the images The camera calibration report provides data about the camera such as the focal length fiducial coordinates and radial distortion parameters For more information see Understanding Camera Calibration Data on page 21 Click Digital Video Camera when the frame images are generated from CCD arrays Charged Coupled Devices A camera calibration report is often not supplied with the images However most companies that provide calibration services for standard aerial cameras can provide camera calibration services for digital and video cameras for more information see Understanding Camera Calibration Data on page 21 The minimum measurements required are the focal length which is OrthoEngine User s Guide Chapter 2 Starting your Project and Selecting a Math Model determined when the lens is set
5. Entering the Camera Calibration Data on page 24 Defining Fiducial Marks Fiducial marks are small crosses or small V shaped indents located precisely on each of the four corners and or exactly midway along the four sides of a standard aerial photograph Images taken with digital or video cameras do not contain fiducial marks After you identify the fiducial marks in your scanned image OrthoEngine uses the fiducial marks entered from the camera calibration report to establish an image coordinate frame The fiducial mark coordinates are a compulsory parameter for standard aerial photographs To enter the coordinates see Entering the Camera Calibration Data on page 24 If you do not have calibrated fiducial coordinates you can estimate the reference frame by using a ruler to measure distance between the fiducial marks on the paper print or diapositive using the corners of the exposure not the corners of the file or paper as fiducial marks if you have scanned the entire print To enter the measurements click Compute from Length in the Standard Aerial Camera Calibration Information window and type the measurements in the Top Edge Length Right Edge Length Bottom Edge Length and Left Edge Length boxes OrthoEngine User s Guide 23 Chapter 4 Setting Up Camera Calibration and Aerial Photographs To collect the fiducial marks in the scanned image see Collecting Fiducial Marks Manually on page 25 Defi
6. Normally the cursor and the screen share the same focus In the 3 D viewer however the cursor can move not only in x and y but also in z This means that the cursor can appear as if it is floating off the screen or behind the screen While performing feature extraction press F or F3 to refocus your images to the elevation of the cursor Press F4 to refocus and center images in the viewer Minimize the offset between your left and right images Raw images in the 3 D viewer do not usually align Epipolar images usually align but might need some adjustments Misaligned images can make it difficult or impossible to see in stereo and it can put stress on your eyes As you move from one area to another in the stereo pair press I J K or M to shift the right image to align with the left Remember to adjust the elevation of your cursor If the two crosshairs of the stereo cursor do not coincide the cursor is probably far above or below the terrain Press G or F2 to move the cursor to the ground elevation Recenter the images Working in the middle of the 3 D viewer is easier on your eyes Since the 3 D viewer and the normal screen display information differently your eyes may have difficulty adjusting to both environments at the same time Press R or F1 to recenter the cursor and images Examining the 3 D Feature Extraction Work Flow To create or edit vectors in 3 D 1 Select a stereo pair see Selecting the Stereo Pair on p
7. OrthoEngine can estimate the position of the point by using an automatic correlation method once it has enough information to calculate the math model Therefore the project must have ephemeris data for satellite imagery GPS INS data for aerial photography a minimum number of GCPs or three tie points per image for Auto Locate to work You should verify the estimated positions and adjust them if necessary before accepting them The cursor will be placed automatically on the pixel and line position of the selected point in all the open images at a default zoom level when Auto Locate is selected and you Select an existing point in a GCP Collection window Type the elevation and coordinates under Georeferenced Position in a GCP Collection window Accept a new tie point in the Tie Point Collection window Accept a new elevation match point in the Elevation Match Point Collection window OrthoEngine User s Guide 35 Chapter 5 Collecting Control Points and Computing the Math Models Using Bundle Update The Bundle Update feature appears on the GCP Collection windows and the Tie Point Collection window when you are creating a project using a rigorous model When you select Bundle Update OrthoEngine performs the bundle adjustment every time you add a point to the project This can help you determine whether the point that you collected is good enough for your project For more information see Understanding th
8. The Sampling Interval determines how many output pixels are computed following that method A Sampling Interval of 1 means that every output pixel is processed However processing every output pixel can take a significant amount of time and it may not be necessary To speed up the process you can increase the Sampling Interval which means that OrthoEngine computes the correction for some pixels and interpolates those in between For example a Sampling Interval of 4 means that the correction for every fourth pixel is calculated and the correction for the pixels in between are interpolated Hints for use with Orthorectification When you have high resolution images such as aerial photographs and a high resolution DEM a lower Sampling Interval is recommended to ensure that sharp changes in elevation are corrected during orthorectification When the resolution of your images is higher than that of your DEM use a higher Sampling Interval In this case many output pixels will fall within the boundaries of a single DEM pixel so using a higher interval speeds up the process without compromising greatly on the output If you do not want to use all the detail in your DEM use a higher Sampling Interval If you want to perform a trial run of the orthorectification to verify the results use a higher Sampling Interval It will increase the processing speed 102 PCI Geomatics Understanding the Status Descriptions Hints f
9. The elevations are calculated from the parallax between the corresponding ground control points GCPs tie points and elevation match points in the images 64 PCI Geomatics Using Vectors to Generate a Digital Elevation Model The DEM can be fairly accurate for relatively flat areas however it is not recommended for rough areas since you would have to collect a large number of points to accurately represent the terrain To collect elevation match points 1 On the OrthoEngine window in the Processing Step list select Import amp Build DEM 2 Click 3 i the DEM from GCPs Tie points Match points icon 3 Onthe Elevation Match Point Collection window the Point ID is generated automatically You can type a new label in the Point ID box however all points ground control points check points tie points and elevation match points in the image must have unique labels 4 Youcan select Auto Locate to aid with collection For more information see Using Auto Locate on page 35 5 Inthe Photo Layout window under Overview double click the crosshairs of two overlapping images 6 Choose a feature that appears in both images At a zoom level where you can see the detail in one ofthe images position the cursor precisely on the feature and then click Use Point At a zoom level where you can see the detail in the second image position the cursor precisely on the same feature and then click Use Point The pixel and
10. The minimum and maximum elevations are used to estimate the search area for the correlation This increases the speed of the correlation and reduces errors If the resulting DEM contains failed values on peaks or valleys increase the range 10 11 12 In the Failure Value box type the value used to represent the failed pixels in the resulting DEM Specifying a failure value will assist you in interpolating these pixels when you edit the DEM In the Background Value box type the value used to represent the No Data pixels in the DEM The No Data or background identifies the pixels that lie outside the extracted DEM overlap area so they are not mistaken for elevation values In the Pixel Sampling Interval list click the number of image pixels and lines sampling frequency that will be used to extract one DEM pixel For more information see Understanding Pixel Sampling and DEM Detail on page 73 Using a Pixel Sampling of one pixel is not recommended to derive a DEM for RADARSAT data because of the difficulties with correlating the speckle inherent in all SAR data In the DEM Detail list click the level of detail that you want in the extracted DEM For more information see Understanding Pixel Sampling and DEM Detail on page 73 Select Use Clip Region if you want to process only the area determined in the Define Clip Region window which results in smaller DEMs and faster processing To create t
11. 96 PCI Geomatics 7 477 4 Correcting Your Images Se A N MXN v o gt gt ts U ndersta nd i ng Orthorectificati on Figure 8 1 Using sensor geometry and a DEM to orthorectify imagery sensor Orthorectification is the process of using a rigorous math model and a digital elevation model DEM to correct distortions in raw images as shown in Figure 8 1 The rigorous math models such as the Aerial Photography or Satellite Orbital math models provide a method to calculate the position and orientation of the sensor at the time when the image was taken The DEM is a raster of terrain elevations For more information about math models and DEMs see Understanding the Math Models on page 5 and Understanding Digital Elevation Models on page 63 raw image the result of orthorectification The quality of the orthorectified image is directly related to the quality of the rigorous math model and the DEM A poorly computed math model an inaccurate DEM or a DEM incorrectly georeferenced to the math model will cause errors in the orthorectified images ortho at datum correct incorrect pixel relief displacement error 97 Chapter 8 Correcting Your Images Orthorectifying Your Images Before you orthorectify your images you must ensure that the Output Pixel Spacing on the Set Projection window is set correctly For more information see Setting the Projection on page 13 The Output
12. Click Print to File 132 PCI Geomatics Saving the Project as a Template 8 In Report File type the path for the text file or click Select to choose a location 9 Click Append to the report to an existing file or click Overwrite to replace or create a file Saving the Project as a Template When you save your project as a template the template retains the information that you entered in the Project Information window the Set Projection window the Standard Aerial Camera Calibration Information window and the math model To save the project as a template 1 Open a project 2 Inthe main menu click File 3 Click Save as Template 4 Type a filename in the File name box 5 Click Open Using the File Utility You can use the File Utility to view detailed information about selected GeoGateway file and edit some of the information depending on the GeoGateway format type and the read write status of the file Viewing an Image Outside Your Project To open an image that is not a part of your project 1 Click File from the main menu 2 Click Image View 3 Select an image For information about the features available in the viewer see Understanding the Enhancements on page 121 Using Zoom ReLoad and Pan on page 122 Loading Vectors Over an Image Cursor Control and Changing Image Color Channels on page 123 Understanding Format Descriptions for Text Files Containing G
13. He step in your project For projects using the Aerial Photography or Satellite Orbital math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Collecting Ground Control Points from a Geocoded Image You can use existing geocoded images as a source for ground control points GCPs By matching the coordinates of points in the geocoded image to pixel and line coordinates in the raw image you can collect as many GCPs as you want If you have several raw images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The GCP Collection window collects and displays the GCPs from the image in the Working viewer only Click the Reference button to switch the viewer to Working You can collect the same GCP in each image by clicking Reference in a viewer collecting the GCP and then repeating the process for each image 2 s Tip If you are working in a project with a large volume of images we recommend that you enter the fiducial marks and ground control points for a limited number of images up to five complete the bundle adjustment for the math model and then check for errors before continuing It is easier to locate bad points on a few images than over the entire project To collect ground control points from a geocoded image 1 On the OrthoEngine window in the Processing Step l
14. Accept Delete New Point 15 At a zoom level where you can see the detail in the raw image position the cursor precisely on the feature that you will use as a GCP and click Use Point Latitude The pixel and line coordinates from the raw image appear in the GCP Collection window under Image Position or Photo Position If you need to enhance the chip image to determine the position of the ground coordinate you can use the features available under Image DEM Chip For more information about how to enhance the chip image see Adjusting the View Under Image DEM Chip on page 43 16 On the GCP Collection window under Georeferenced Position click Accept The GCP is added to the Accepted Points table Tip You can edit the error estimate in the boxes under Image Position to correspond to your ability to precisely identify a feature in the image For example if you use coarse imagery you can probably only measure to the closest pixel If you use imagery that was compressed or poorly scanned you may only be able to measure to the closest two pixels Even if you identify a GCP to the closest pixel the coordinate may only be accurate to so many meters Grex step in your project For projects using the Aerial Photography or Satellite Orbital math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Searching for
15. Collecting Control Points and Computing the Math Models On the GCP Collection window under Auxiliary Information you can click Display Chips to display the geocoded locations of the chips on your raw image once you have enough information to calculate the math model 11 If you want to change the position of the GCP in the chip select a new point in the chip image and click Cursor Position is GCP To change the GCP location in a chip the Chip Database must be writeable and the chip image must be geocoded 12 Click Use Image Chip in the OrthoEngine ChipDatabase window OrthoEngine attempts to find the corresponding feature in your raw image and positions the cursor on the feature The feature s Easting and Northing coordinates appear in the GCP Collection window 13 If the chip does not contain the elevation of the point you can use another source On the GCP Collection window under Georeferenced Position in the Elev box type the elevation of the GCP or you can use a digital elevation model DEM to determine the elevation of your GCPs see Using a Digital Elevation Model to Set Ground Control Point Elevation on page 51 14 On the GCP Collection window in the boxes beside the Elev box the Easting box and the Northing box type the estimated error for each Georeferenced Position UTM 17 U E008 Elevation gt Elev 2 000 m Easting b5 Northing gt 05 WN Longitude td Lat
16. Detail DEM Extraction uses image correlation to find matching features on the left and right image of a stereo pair The best way to find these matching features is a hierarchical approach using a pyramid of reduced resolution images The first attempt at correlation is performed on very coarse versions of the images This enables OrthoEngine to match prominent features accurately which forms the basis for further correlation attempts The next correlation attempts are performed to match finer features on higher and higher resolution versions of the images Finally correlation is performed on images at full resolution which provides the highest precision for the terrain in the digital elevation model DEM This correlation technique speeds up the image correlation process and reduces the number of mismatches DEM Detail and Pixel Sampling control the type of DEM that you want to produce OrthoEngine User s Guide 73 Chapter 6 Generating Digital Elevation Models DEM Detail determines how precisely you want to represent the terrain in the DEM Selecting High Medium or Low determines at which point in correlation process you want to stop Low means that the process stops during the coarse correlation phase on aggregated pixels so the level of detail in the DEM will be quite low High means the process continues until correlation is performed on images at full resolution Pixel Sampling controls the size of the pixel in the
17. Geocoding a Digital Elevation Model on page 79 If you have geocoded the DEM your DEM is finished Creating a Mask A mask identifies specific areas that you want to edit The mask does not change the values in the area that it covers To edit the area under the mask see Replacing the Elevation Values Under a Mask on page 76 Feature Purpose Procedure Trace Draw an irregular line Click Trace and drag the cursor over the area that you want to edit Trace amp Close Draw an irregular Click Trace amp Close and drag shape the cursor around the area you want to edit The shape closes automatically PolyLine Draw a line of straight Click PolyLine and click in segments the viewer over the area you want to edit OrthoEngine User s Guide Chapter 6 Generating Digital Elevation Models Feature Polygon Fillg Cursor Purpose Draw a polygon Fill the polygon or irregular shape Procedure Click Polygon and click in the viewer around the area you want to edit Click Polygon again to close the polygon Make sure that the mask that you want to fill is closed If the shape or polygon is open the fill will cover the entire DEM Click Fill Cursor and click the mask that you want to fill If you want to fill several masks consecutively click Fill Cursor and right click the masks Fill Failed Cursor Create a mask over an area of pixels with failed values
18. Geomatica s Generic Database GDB technology provides you with seamless and direct geospatial data transfer capabilities which means that you can import export or read directly over 100 raster and vector formats OrthoEngine supports images from standard aerial digital and video cameras and data from satellite sensors such as ASAR ERS JERS QUICKBIRD ASTER IKONOS e LANDSAT RADARSAT AVHRR IRS MERIS SPOT EOC OrthoEngine s interface is organized along logical workflows to produce orthorectified or geometrically corrected images digital elevation models DEMs three dimensional vectors and mosaics This structure provides you with a more intuitive workflow N CHAPTER N PEE BN E Se x A N e CNN Se EN Eo n A To help you complete your projects more efficiently OrthoEngine includes several features that can save you time and effort and will provide you with more accurate results For example Rigorous math models produce robust orthorectification of aerial and satellite imagery such as QuickBird data The enhanced viewer offers increased zoom capabilities panning brightness contrast cursor control and mapping color channels Automatic fiducial mark collection saves time when you import photos Automatic tie point collection quickens the tedious process of collecting tie points Epipolar batch processing converts a group of stereo pairs into epipolar image pairs wh
19. New file will be created The corrected image will be saved on the disk OrthoEngine User s Guide 103 Chapter 8 Correcting Your Images Troubleshooting Your Orthorectified Images Features that would be straight in a planimetric map such as roads power lines edges of buildings and edges of lots should also appear straight in an orthorectified image If they do not then you may have errors in your digital elevation model DEM or math model solution Re verify the DEM and the math model solution If the file for the orthorectified image is too large or too small it may indicate that The DEM area does not cover the image area The DEM is not in the same projection as the image The Background Value of the DEM is incorrect The math model s elevation values are incorrect The focal length of camera is incorrect If the orthorectified image appears smeared it could indicate that The DEM is misaligned with the math model of the image The DEM does not have a sufficient resolution to orthorectify the image For example cliffs and buildings can appear smeared if the DEM is too coarse to precisely represent the edge of the cliff or the building If overlapping orthorectified images do not align it could indicate that The math model contains errors which means that you need to edit the model or add more GCPs and tie points The DEM contains errors or contains insufficient detail to correctl
20. X Part of X location Y Part of Y location S The sign or of the following number B Generic place holder Any character not in this list is used for verification when converting raw data into points You can use a maximum of two button characters unless the button number is hexadecimal When the button number is hexadecimal you can use only one button number You must use either M N or H to indicate the button pressed For example the SummaGraphics Microgrid generates an ASCII string in the following format SXXXXX SYYYYY NN T Where S is the sign or of the number XXXXX are five digits giving the x location YYYYY are five digits giving the y location NN is the number of the button pressed in this case a number between 0 and 16 T is a tablet area identifier Format string rules 1 A sign character if present must occur immediately before the XXX or YYY characters otherwise it will be ignored 2 Only the first occurrence of XXX YYY and NN in the format string are used others are ignored The tablet configurations are stored in a text file SPCIHOME etc tablet def that contains a number of parameters which define a tablet Each parameter must appear on a separate line A tablet is defined by the following parameters 60 PCI Geomatics Defining the Tablet Format Strings TABLET tablet number NAME tablet name INITIALIZE init string FORMAT format string
21. collect tie point automatically 53 collect tie point manually 52 to generate DEM 64 understanding 51 Tie Point Distribution Pattern 54 TIFF 128 TIN 65 Tolerance 68 Toutin s Model 10 TP Collection 53 Trace 75 Trace amp Close 75 transformations Polynomial 8 Thin Plate Spline 8 transmit coordinate from tablet 49 Troubleshooting orthorectified Images 104 the math model solution 56 U undo vectors 90 Urban Areas 78 Use bounds and resolution 67 Use Grid Pinning 47 Use Image Chip 42 Use pixels lines and bounds 67 Use pixels lines and resolution 67 User Defined Filter 106 User Input 10 27 USGS Digital Orthophoto Quads and Quarter Quads 64 Utilities converting the DEM datum 126 remove image from project 124 rename image 124 replace pixel values 125 Stitch Image Tiles 126 Sync Images 125 Utilities Chip Manager 138 139 140 V Valleys 2D 66 Vector File 66 vectors add lines 88 add points 88 add polygons 89 Attribute table 92 93 change color 123 change priority of layers 87 delete a layer 94 delete line or polygon 92 delete vertex 91 editing tools 90 extracting lines from DEM 96 extracting points from DEM 95 import 122 import layers 87 insert vertex 91 metadata 92 93 move vertex or point 92 save a layer 93 snap 90 to generate DEM 65 67 undo 92 Video Camera 9 video camera calibration 21 view an image 17 133 view image during DEM editing 75 view selected GCPs 44 view the coordinates 123 viewer Chip Manage
22. compensate for the relief displacement As a result you collect the correct planimetric positions x and y coordinates and accurate elevations z coordinates for the features By using an anaglyph display and 3 D glasses or special stereo viewing hardware you can present your left eye with only the left image and your right eye with only the right image from the stereo pair Your brain will automatically correct the geometric effects of sensor geometry and relief displacement Similarly the stereo cursor is actually made of two cursors one only displayed to the left eye and the other only displayed to the right eye By adjusting the difference in x coordinate or parallax between the left and right cursors you control the apparent height of the cursor This way you can position the cursor not only in x and y but also in z You can more easily recognize the features measure and record accurate coordinates for the features and collect planimetrically correct vectors in the 3 D environment He step in your project See Examining the 3 D Feature Extraction Work Flow on page 83 81 Chapter 7 Editing Features in 3 D Stereo Viewing in 3 D Using Anaglyph Technology Anaglyph technology uses a standard monitor to simulate a three dimensional 3 D view of the images The left image is displayed in red and the right image is displayed in blue When you wear red blue anaglyph glasses the red lens filters out the
23. elevation model DEM to determine the elevation of your ground control points GCPs The DEM does not have to be in the same projection as the source of the GCPs To use a DEM to set the GCP elevation 1 Onthe GCP Collection window under Auxiliary Information click Select 2 On the Database File Selection window select the file and click Open 3 On DEM File window select the database channel containing the elevation 4 Inthe Background Elevation box type the value representing the No Data pixels in the DEM and click Select If you do not know what the background value is click DEM Info The DEM INFO window displays the three lowest and three highest values The background value is usually a dramatically different value such as 150 or 999 999 5 Onthe GCP Collection window under Georeferenced Position enter the Easting and Northing values by using one of the GCP collection methods 6 Under Auxiliary Information click Extract Elevation Understanding Tie Points A tie point is a feature that you can clearly identify in two or more images and that you can select as a reference point as shown in Figure 5 2 Tie points do not have known ground coordinates but you can use them to extend ground control over areas where you do not have ground control points GCPs Used only in rigorous models such as Aerial Photography and Satellite Orbital math models tie points identify how the images in your project relate to
24. the Define Clip Region icon In the window with the open image click on the red guidelines and drag to frame the area that you want or in the Define Clip Region window type the image coordinates of the upper left corner in the Upper Left Corner X box and the Upper Left Corner Y box To determine the clip region size type the number of pixels in the X Size box and the number of lines in the Y Size box To move the Clip Region click inside the region and drag it to its new position Click Done OrthoEngine User s Guide 31 Chapter 4 Setting Up Camera Calibration and Aerial Photographs 32 PCI Geomatics Understanding Ground Control Points A ground control point GCP is feature that you can clearly identify in the raw image for which you have a known ground coordinate Ground coordinates can come from a variety of sources such as the Global Positioning System GPS ground surveys existing geocoded images vectors or Geographic Information Systems GIS topographic maps chip databases or by using photogrammetric processes to extend the number of GCPs in your images The GCPs are used to determine the relationship between the raw image and the ground by associating the pixels P and lines L in the image to the x y and z coordinates on the ground Ho step in your project See one of the following Collecting Ground Control Points Manually on page 36 Collecting Ground Control Points from a Geocode
25. white to the color specified for the selected layer in the Vector Layer Information table 7 You can repeat steps 3 to 6 until you have collected the polygons that you want for the selected layer 8 Click New Poly to stop collecting polygons 2 s Tip When you are working with the stereo cursor in the 3 D viewer you can press G to snap the stereo cursor to the ground press ENTER to confirm the completion of the polygon press O to activate and deactivate New Poly For more shortcuts see Using Shortcuts in the 3 D Viewer on page 94 tex step in your project See Designing the Attribute Table on page 92 Using Snap to Vertex Snap to Vertex places the cursor on the vertex nearest to where you click You can use it to quickly position new vertices or to move existing vertices on the same layer When you are working with the stereo cursor in the 3 D viewer you can press V to activate and deactivate Snap to Vertex For more shortcuts see Using Shortcuts in the 3 D Viewer on page 94 To snap to a vertex 1 Click Snap to Vertex 2 Position the stereo cursor close to an existing vertex and click The cursor aligns with the vertex nearest to where you clicked 3 ClickSnap to Vertex to turn off the feature You can turn on or off Snap to Vertex at any time while you are collecting or editing vertices Using Snap to Line Snap to Line places the cursor on the line nearest to where you click You can
26. 0j 0k 0 nt n2 n3 e A Q y gt Bijk xn Yn Zn 1 0j 0k 0 where Aijk and Bijk Polynomial coefficients The maximum power for each ground coordinate m1 m2 m3 n1 n2 and n3 is limited to 3 and the total power of all three ground coordinates is limited to 3 That is the polynomial coefficients are defined to be zero whenever i j k gt 3 Understanding the Polynomial Math Model The Polynomial Math Model is a simple math model that uses a first through fifth order polynomial transformation which is calculated OrthoEngine User s Guide Chapter 2 Starting your Project and Selecting a Math Model based on two dimensional 2 D ground control points GCPs This math model produces the best fit mathematically to a set of 2 D GCPs on an image The polynomial equations are fitted to the x and y coordinates of the GCPs by using least squares criteria to model the correction in the image without identifying the source of the distortion You can choose one of several polynomial orders depending on the desired accuracy and the number of GCPs available First order polynomial transformations can model a rotation a scale and a translation As up to 21 additional terms are added giving a fifth order polynomial you can achieve more complex warping However using a lower order transformation reduces the time needed to complete the correction and less geometric distortion may occur in areas with no GCPs The resul
27. 55 Chapter 5 Collecting Control Points and Computing the Math Models To compute the rigorous math model 1 On the OrthoEngine window in the Processing Step list select Model Calculations ES 2 Onthe OrthoEngine window click the Perform Bundle Adjustment icon Grex step in your project For the next step in your project see Troubleshooting the Math Model Solution on page 56 Understanding the Solution for Simple Math Models The computation of the simple models is done automatically as you add ground control points GCPs to the project The image is not manipulated at this point The simple math model uses the GCPs to calculate a transformation that will warp the raw image to fit the ground coordinates Since the math model calculates a solution for each image no tie points are used Rational Functions The rational functions math model solution uses the GCPs to build a relationship between the pixels and the ground locations To evaluate the accuracy of your model see Troubleshooting the Math Model Solution on page 56 rw step in your project For Rational Functions projects see Understanding Digital Elevation Models on page 63 Understanding 3 D Stereo Viewing and Editing on page 81 or Geometrically Correcting Your Images on page 101 Polynomial The Polynomial math model s solution is used to warp the raw image around the GCPs to fit the ground coordinate system To eva
28. Additional Features difference between the coordinates that you entered for the ground control points GCPs or tie points and where the points are according to the computed math model For more information about the Residual Report see Troubleshooting the Math Model Solution on page 56 OrthoEngine recalculates the math model several times to find the best possible solution The best possible solution is determined when the residual errors of the GCPs and tie points fall within the limit set in the XYZ Threshold the Angle Threshold or until the limit in the Number of Iterations is reached By adjusting the thresholds you control the precision of the model To change the threshold values 1 Inthe main menu click Options 2 Click Bundle Options 3 In Number of Iterations type the maximum number of times that OrthoEngine can recalculate the math model solution 4 Inthe XYZ Threshold box type the acceptable deviation in pixels for the coordinates 5 In Angle Threshold type the acceptable deviation in degrees for the the Omega Phi and Kappa angles 6 Click Close Generating a Project Report To generate a Project Report 1 On the OrthoEngine window in the Processing Step list select Reports 2 Click E the Project report icon a oe 3 Under Project Information select General to include the filename and description of the project from the Project Information window Output mosaic to include i
29. Chips in a Database In some cases you might want to narrow the search for chips to a manageable number of possibilities By defining the search parameters such as the sensor a range of acquisition dates or a region of interest you can limit the chips that you want to use in the matching process 42 PCI Geomatics Collecting Ground Control Points from a Chip Database Automatically To search for a chip 1 On the OrthoEngine ChipDatabase window click Search Criteria 2 On the Searching Chip Database window type the parameters that you want 3 Click Do Search The results of the search are displayed under List of Chips Matching Search Conditions 4 If your search was not satisfactory click Restore Defaults to reset the window and enter a new set of parameters 5 For projects using satellite imagery You can click Default ROI to Image to use the orbital data from a raw image database to estimate the parameters under Region of Interest ROI within a 50 margin of error If you have collected more than three GCPs OrthoEngine can compute an affine model to help estimate the ROI parameters within a 25 margin of error 6 When you are satisfied with your chip selection click Close Working with the Chip Database To search for chips see Searching for Chips in a Database on page 42 Changing the Color of the GCP or Cursor in the Chip In Image DEM Chip click Colors to change the color of the ground
30. Click Fill Failed Cursor and click the area that you want to fill If you want to fill several areas consecutively click Fill Failed Cursor and right click the masks If the area does not fill with a mask the area may not contain failed values or you may have set the failed value incorrectly Fill all Failed Create a mask over all the failed values in the DEM Click Fill all Failed If masks do not appear the DEM may not contain failed values or you may have set the failed value incorrectly Feature Purpose Procedure Clear Mask Erase the mask Click Clear Mask to remove the mask from the viewer Show Mask Show or hide the Click Yes to display the mask mask in the viewer Click No to hide the mask You can edit the values under the mask whether the mask is visible or not Change the color of the mask Select a color from the list beside Show Mask Line Drawing Width Determines the thickness of the mask Type or select the size that you want Replacing the Elevation Values Under a Mask To replace the elevation values under a mask with a new value 1 Create a mask For more information see Creating a Mask on E g page 75 2 Under Area Fills Under Mask in the Value box type the value that you want to place under the mask 3 Click Fill Using Value 4 Click Clear Mask 2 Tip For example you want to correct a lake in your
31. Click to move the selected vertex 5 Click Accept or press ENTER to accept the move Reversing an Action Undo Click Undo to cancel the last action made in the 3 D viewer You can restore the action by clicking Redo However you cannot cancel actions that delete vectors or vertices and Undo only functions for actions that have not been accepted by clicking Accept pressing ENTER and so on Designing the Attribute Table Each row in the Attribute table represents a vector on the selected layer Attributes are numeric or text values that describe the vector such as a road name the tree height the date of data collection or a feature representation code used for cartographic production Before you can add attributes to a vector you need to define the columns in the table For each column you can define several parameters and you can change the parameters except Type at any time To add a new column to the Attribute table 1 Click Fields 2 Onthe Vector Field Definition window click Add Field 3 In New Field window in the Name box type the heading for the column The heading can contain any number of characters including valid ASCII printable characters 4 Inthe Description box type a brief sentence describing the column or a list of acceptable attribute values 5 Inthe Data Type list select Integer to define the field as containing positive or negative whole numbers Double to define the field as containi
32. Creating Chips from a GCP Segment You can create chips from an image that contains a ground control point GCP segment A GCP segment is a channel included in an image file that contains the x and y coordinates the pixel and line coordinates and the elevation for GCPs in the image You can use only GCP segments that contain a pair of UTM coordinates and pixel and line coordinates to create chips To create a chip from a GCP segment 1 Create or open a database For more information see Creating a New Database on page 135 or Opening an Existing Chip Database on page 136 2 Opena source image that contains a GCP segment For more information see Selecting the Source for the Chips on page 136 3 Inthe main menu click Utilities 4 Click Use GCP Segment and click From Image 5 Select a segment 6 Under GCP List click a GCP and click Use Selected GCP as Chip 7 On the viewer displaying the source image click Chip Size and specify the size of the chip For more information see Determining the Size ofthe Chip on page 137 8 Onthe PCI ImageChipsManager window in Save Option click Chip Only if you want to save the chip without the overview Chip and Overview if you want to save the chip with the overview In the list select the size of the overview window The overview provides a view of the area surrounding the chip 9 Inthe Chip ID box type the label for the chip The Sensor Acquisition Genera
33. DEM You can create a mask over the lake find the lake s true elevation from a map type the elevation value in the Value box and click Fill Using Value PCI Geomatics Editing the Digital Elevation Model To replace the elevation values under a mask with an average value 1 Create a mask For more information see Creating a Mask on page 75 2 Under Area Fills Under Mask click Fill Using Average Average displays the average mean of all the elevation values under the mask 3 Click Clear Mask 2 s Tip For example you decide that a residential area in the DEM is too rough You can create a mask over the area and click Fill Using Average To replace the elevation values under several masks with their average values You can create masks over several different areas and replace the values under each mask with the average mean of all the elevation values under each mask Therefore OrthoEngine calculates the average under each mask independently and fills each area with its own average l Create several masks For more information see Creating a Mask on page 75 2 Click Fill Each Polygon with Polygon Average 3 Click Clear Mask Bulldozing a Line Bulldoze a Line is a combination of Trace and Fill Using Value As you drag your cursor over an area the masked area is filled with the value that you set To bulldoze a line 1 Under Bulldoze a Line in the Value box type the value tha
34. Difference for the Cutline Selection Method OrthoEngine User s Guide 119 Chapter 9 Mosaicking Your Images 120 PCI Geomatics Additional Features Understanding the Enhancements Enhancements make the image on the screen clearer and easier to interpret without changing the values in the image file The enhancements available in the Enhance list change depending on the viewer None removes all the enhancements Linear uniformly stretches the minimum and maximum values in the image over the entire available output display range to enhance the overall differences in gray levels in the image Root compresses the range of higher values brightness and expanding the range of lower values darkness so you can distinguish more detail in darker areas of an image while still retaining some detail in the brighter areas Equalization or Equal distributes the values equally over the entire output display range resulting in an almost uniform histogram This enhancement is effective in exposing details in the higher values brightness and lower values darkness but causes less contrast in the middle values e AP TER Y gt m M X EN AN SR q EEN E Adaptive combines the benefits of Equalization and Linear enhancements resulting in a more natural display than Equalization while effectively compensating for outliers Infrequency assigns the values that occur the least frequently in the image t
35. Pixel Spacing determines the resolution of the orthorectified images By default the channel type for your orthorectified images is the same as your input channel To change the output channel type see Setting the Channel Type for Your Output Image on page 129 For more information about the status displayed in the Ortho Photo Production window see Understanding the Status Descriptions on page 103 To start processing your image 1 On the OrthoEngine window in the Processing Step list select Ortho Generation 2 Click LIP the Schedule ortho generation icon 3 Under Available Photos select the images that you want to process and click the arrow button to move the images under Photos to Process The images are processed in the order that they appear under Photos to Process If you have already orthorectified the image Delete existing file appears next to the image When the image is orthorectified the previous version is replaced If you have not orthorectified the image previously Create new file appears 4 Under Photos to Process select an image 5 In Input Channels click All to select all the image channels or click Channels and type the channels that you want in the Channel box You can use a dash between the channel numbers to indicate a range and a comma between individual channel numbers Repeat step 5 for the remaining images or select Apply input channel selection to all files to use the same channe
36. R Im for Ci lt Cu R Im W Ic 1 W for Cu lt Ci lt Cmax R Ic for Ci gt Cmax where W exp Damping Factor Ci Cu Cmax Ci Cu SQRT 1 Number of Looks Ci S Im Cmax SQRT 1 2 Number of Looks Ic center pixel in the frame Im mean value of intensity within the frame S standard deviation of intensity within the frame The Damping Factor specifies the extent of the damping effect of filtering OrthoEngine uses a default value of 1 since it is sufficient for most SAR images The Number of Looks and the Image Format of the radar image are usually recorded on the CD jacket or magnetic tape label or in the format specifications provided by the data vendor Filter Size The frame must be square with its width and length in odd numbers You control the size of the frame with the Filter Size option by typing the number of pixels width in the X box and the number of lines length in the Y box Different filter sizes greatly affect the quality of the processed images If the filter is too small the noise filtering algorithm is not effective If the filter is too large subtle details of the image are lost in the filtering process The minimum size for the frame is 3 by 3 pixels A 7 by 7 frame usually gives the best results Image Format The radar images are supplied in one of two Image Formats Power or Amplitude Power is the sum of the squares of the real and imaginary values of the complex pix
37. You can rotate your photographs until the tops are closest to North so they correspond to the map coordinate reference frame which makes collecting ground control points GCPs easier You can rotate the photographs so that the along strip overlap is along a left to right axis which makes tie point collection easier and is convenient for projects that require stereo overlap such as digital elevation model DEM extraction To change the Photo Orientation 1 On the OrthoEngine window in the Processing Step list select Data Input ejs 2 Click the Change photo orientation icon 3 Under Location for Rotated Photos click Same directory as Input Photo to save your rotated photographs in the same folder as the raw photographs All Output to this Directory and type the path in the box underneath or click Browse to select a folder Select Delete Input Photo when complete to delete the raw photographs from the disk Under List of Photos to Rotate in the Rotate Flip column click the boxes corresponding to the photographs that you want to rotate or flip or click All to select all the available photos The Input File column shows the filenames of the raw photographs The Output File column shows the filenames that will be used for the rotated photographs By default the output filename is the input filename appended with R with the same extension You can change the filename by clicking the output filename and typing th
38. add the information to an existing file Overwrite to replace the information in the file with the new information Exporting to Supresoft Format You can export the exterior orientation interior orientation and camera calibration data to a folder for use with Supresoft IMAGIS OrthoEngine will generate text files for each image in the project containing the required information in a format supported by Supresoft To export the text files to a folder 1 Create an empty folder directory 2 Inthe main menu click Options 3 Click Export 4 Click Supresoft Format Data 5 In Directory type a path to the empty folder If you do not know the path you can Click Browse Click Choose Directory Select a folder Click OK 6 Click Write Changing the Default Color Ground Control Points and Tie Points To change the default color 1 Inthe main menu click Options 2 Click Customize Colors 3 Click GCP Color to change the default color of the ground control point GCP indicator as it appears in the viewer TP Color to change the default color of the tie point TP indicator as it appears in the viewer 4 Click the color that you want Setting the Threshold Values for the Math Models Bundle Options The Residual errors in the Residual Report will help you determine if the solution is good enough for your project Residual errors are the OrthoEngine User s Guide 131 Chapter 10
39. addition to reducing your work load Automatic Mosaicking will often produce a more seamless look than if you had attempted to create the mosaic by hand To automatically mosaic your images Before you attempt Automatic Mosaicking you must define a mosaic area see Defining a Mosaic Area on page 112 1 On the OrthoEngine window in the Processing Step list select Mosaic 2 Click the Automatic mosaicking icon 3 Inthe Automatic Mosaicking window click in the Use column to select or clear the images The images with check marks in the Use column will be mosaicked You can also use the Orthos in Mosaic buttons to select or clear the images click All to select all the available images Gray check marks indicate images outside the defined mosaic area None to clear all the images selected in the Use column Allin Mosaic to select only the images that appear in the region that you set in Define Mosaic Area OrthoEngine User s Guide 113 Chapter 9 Mosaicking Your Images 4 Normalization is used to even out the maximum and minimum effects in tone to achieve a more pleasing mosaic You can set the feature differently for each image by clicking the corresponding arrow beside the Normalization column or you can set it for all the images by selecting the feature in the Normalization list and clicking Apply to All Select None to leave the images as is Hot Spot to remove hot spots from the imag
40. and the chip size which can be obtained from the camera manufacturer 7 In the Exterior Orientation list select the source of the exterior orientation for your project Click Compute from GCPs and tie points when you intend to use known points and or coordinates on the ground to establish the camera s position when the image was taken Click User Input when you intend to import the exterior orientation that was calculated in a previous project or by another triangulation software see Setting Up Camera Calibration and Aerial Photographs on page 21 8 Click Accept Tip Many aircraft are equipped with onboard Global Positioning Systems GPS and sometimes with Inertial Navigation Systems INS as well These systems collect the exterior orientation of the camera directly on the aircraft Select User Input to use the GPS and INS readings navigation solution alone and accept them as correct Select Compute from GCPs and tie points to use ground control points and or tie points to refine the GPS and INS results ex step in your project See Setting the Projection on page 13 Starting a Project Using the Satellite Orbital Math Model The Satellite Orbital Math Model is a rigorous model that compensates for known distortions to calculate the position and orientation of the sensor atthe time when the image was taken For more information see Understanding Satellite Orbital Modelling on page 5 To start the
41. are reprojected so that the left and right images have a common orientation and matching features between the images appear along a common x axis Extract DEMs from the overlap between the epipolar pairs The resulting DEMs are called epipolar DEMs They are not georeferenced at this stage Geocode the epipolar DEMs and stitch them together to form one DEM The result is one DEM reprojected to the ground coordinate system DEMs usually contain poorly correlated areas You can correct these areas before or after the DEMs are geocoded Each approach has its advantages Editing the DEM before it is geocoded The epipolar pair and its corresponding epipolar DEM are contained in a single file When you open the file in 2D DEM Editing you can select both the image channel and the epipolar DEM channel so you can switch back and forth between them in the viewer The image will help you identify features in the DEM that need correction For example you can switch between the image and the epipolar DEM to delineate the border of a lake adjust the profile of a shoreline or clean up its edges After you generate the epipolar DEMs you can edit them see Editing the Digital Elevation Model on page 75 geocode them see Geocoding a Digital Elevation Model on page 79 and then integrate OrthoEngine User s Guide 71 Chapter 6 Generating Digital Elevation Models them into one DEM see Using Rasters to Generat
42. control point in the chip and the cursor point in the chip Adjusting the View Under Image DEM Chip You can make the chip on the screen clearer and easier to interpret without changing the values in the image file Imagery Under Image DEM Chip select an image channel in the Imagery list if the chip contains RGB color bands or individual bands in black and white Enhance See Understanding the Enhancements on page 121 Zoom See Using Zoom ReLoad and Pan on page 122 Display Under Image DEM Chip click Chip to view the image specific to the chip or click Overview to see where the chip is located Collecting Ground Control Points from a Chip Database Automatically OrthoEngine can use image correlation to identify the pixel and line locations in the raw image that correspond to the georeferenced positions on the chips For projects using the Satellite Orbital math model OrthoEngine can match images from the chip database to your raw image based on an approximate image model derived from the orbit information For projects using the other math models the matching process can be accomplished if your project meets one or more of the following criteria The exterior orientation of each image was computed based on ground control points GCPs and or tie points You collected three tie points between every pair of overlapping photos For information about tie points see Understanding Tie Points on page 51 You use
43. cursor to the three dimensional surface z coordinate of a feature at the cursor s current position such as a field a roof top or a tree top He step in your project See Adjusting the Alignment in the Stereo Viewer on page 85 Adjusting the Alignment in the Stereo Viewer When the stereo pair of images is loaded into the viewer you may need to adjust the alignment between the images Raw images in particular may require significant adjustments Misaligned images can make it difficult or impossible to see in stereo and it can put stress on your eyes Press I J K or M to shift the right image to align with the left To align the images l To select a different stereo pair P Y aus Click Select Stereopair and start with M step 3 in Selecting the Stereo Pair on 83 PRES sown He step in your project See Creating a Layer on page 85 or Loading a Layer on page 87 Creating a Layer The bounds are set by default to the combined extents of the stereo pair displayed in the three dimensional 3 D viewer You can change the default and make the bounds smaller or larger than the default If you edit a layer with data from another area in the project the bounds automatically enlarge to cover all the data OrthoEngine User s Guide 85 Chapter 7 Editing Features in 3 D Stereo For example you might want to create one layer that covers the entire project By loading that layer
44. determine the size of the frame for the Gaussian Filter Click Browse to select the Kernel File Under Processing Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours Click Generate Orthos A progress monitor displays the status of the images being processed Click Cancel if you want to stop the process o s Tip If you intend to automatically mosaic the processed images you can click Close instead of Generate Orthos When you set up the Automatic Mosaicking window select Regenerate offline orthos and OrthoEngine will process the images and mosaic them in one step OrthoEngine User s Guide 99 Chapter 8 Correcting Your Images He step in your project You can continue with Mosaicking see Defining a Mosaic Area on page 112 Understanding Elevation Scale and Offset The Elevation Scale is used to convert the pixel values in a digital elevation model DEM into their correct elevation value For example since an 8 bit channel can only contain integers between 0 and 255 you may have a DEM that was multiplied by 10 to maintain the decimal precision of its elevation values A DEM pixel may have a value of 102 but the actual elevation that it represents is 10 2 To convert the DEM pixel value from 102 to 10 2 you must multiply it by 0 1 Therefore you type 0 1 in the Elevation Scale box to convert the DEM pixels back to their tru
45. differ from that set in your project By setting the GCP Elevation Units OrthoEngine can convert the values for your project automatically For example you have a project set in UTM projection in meters but your DEM is in UTM projection with elevations in feet If you set the GCP Elevation Units as feet then OrthoEngine will convert the values OrthoEngine User s Guide 127 Chapter 10 Additional Features To set the default units of measurement for GCPs 1 Inthe main menu click Options 2 Click GCP Elevation Units 3 Click Meters or Feet as required Setting a Default Ground Control Point Elevation Datum The elevation reference for GCPs must match the elevation reference of the imagery in your project When you set the projection the elevation datum is set by default If the source of your GCPs differs from that set in your project OrthoEngine can convert the values for your project automatically Elevation values can be referenced to a number of different surfaces but for mapping operations you usually use elevations above Mean Sea Level MSL which is based on a geoid For most math models the model is based on ground control points that are also based on the geoid Two math models are based on orbital information instead of ground control points the RADARSAT Specific Model and the Rational Functions model when it is used with the IKONOS GEO Ortho Kit product Orbit information is always referenced to an
46. each other Figure 5 2 Example of how two images connect through a tie point round coordinates OrthoEngine User s Guide 51 Chapter 5 Collecting Control Points and Computing the Math Models For projects using the Aerial Photography math model you usually collect tie points in a three by three pattern over the photograph as shown in Figure 5 3 Since the photographs have a 60 percent overlap between each other and a 20 percent overlap between the strips you can use the three by three pattern to connect six overlapping photos Figure 5 3 Six overlapping photographs showing the three by three pattern each image contains nine tie points in a three by three pattern the tie point in the center overlaps all six Images Projects using the Satellite Orbital math model generally have fewer images so you can collect tie points wherever overlap occurs Since the overlap between satellite images is unpredictable satellite imagery generally covers a large area containing a lot of ground control Using the tie points in the calculation of the math model ensures the best fit not only for the individual images but for all the images united as a whole Therefore the images will fit the ground coordinate system and overlapping images will fit each other Quote See also Choosing Quality Tie Points on page 52 Choosing Quality Tie Points When you collect the tie points Choose features that you can
47. ellipsoid and the ellipsoid number is taken from the projection information defined in the file To perform a conversion between Ellipsoid and MSL OrthoEngine calculates the difference between the geoid and the ellipsoid at the point in question and then applies the difference to compute the transformed elevation To set the default for the datum 1 Inthe main menu click Options 2 Click GCP Elevation Datum 3 Click Mean Sea Level or Ellipsoidal of your GCP source Changing the Default Orthorectification or Mosaic Output Format By default the output for orthorectification geometric correction and mosaicking is PCI Geomatics s PCIDSK pix format However you do not have to work in PCIDSK format You can import process and export your images using the TIFF format Some software packages support the tiled format for images This format saves the image as a series of tiles so you can open the images on screen more rapidly The tiled format does not produce image tiles that you can later stitch together This format is used solely to improve viewing performance in other software programmes To change the default output format 1 Inthe main menu click Options 2 Click Ortho Mosaic Output Format 3 Click PCIDSK to create a single file in the pix format GeoTIFF to create a single file in the GeoTIFF format GeoTIFF 256 Tiled to save the image in the GeoTIFF format stored as tiles measuring 25
48. estimate in the boxes under Image Position to 9 Inthe Database File Selection window select the geocoded image correspond to your ability to precisely identify a feature in the image For file Click Open example if you use coarse imagery you can probably only measure to the closest pixel If you use imagery that was compressed or poorly scanned The geocoded image opens in a window you may only be able to measure to the closest two pixels Even if you 38 PCI Geomatics Collecting Ground Control Points from Vectors identify a GCP to the closest pixel the coordinate may only be accurate to so many meters He step in your project For projects using the Aerial Photography or Satellite Orbital math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Collecting Ground Control Points from Vectors You can use existing vectors as a source for ground control points GCPs By matching the coordinates of points in the vector file to pixel and line coordinates in the raw image you can collect as many GCPs as you want If you have several raw images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The GCP Collection window collects and displays the GCPs from the image in the Working viewer only Click the Reference button to switch the viewer to Working You can c
49. identify accurately at the resolution of the raw image Select features that are close to the ground Features that rise above the ground such as buildings may appear to lean in the image Therefore a point collected from the top of a feature in one image may be displaced from the same point collected from the top of same feature in another image Avoid using shadows as tie points Although shadows may be easy to see in the image they are not permanent and can move from one image to another Beware selecting common or repetitive features such as parking lots or lines on a highway When you try to identify the feature in the image it may be easy to select the wrong one Select some tie points that appear in three or more images Tie points that join multiple images together produce a more accurate model If available enter the elevation value of the tie point in the Tie Point Collection window see Collecting Tie Points Manually on page 52 Tie points with an elevation value help to control elevation and improve the accuracy ofthe geometric model Collecting Tie Points Manually Used only in rigorous models such as Aerial Photography and Satellite Orbital math models tie points identify how the images in your project relate to each other For more information about tie points see Understanding Tie Points on page 51 You can also automate the tie point collection process see Collecting Tie Points Automatically on page 5
50. if the background value is zero For more information see Mosaicking Images with a Background Value Other Than Zero on page 113 6 Click Create Mosaic File 7 Click Close To select a previously defined mosaic area 1 On the OrthoEngine window in the Processing Step list select Mosaic ooo 2 Click Lj the Define mosaic area icon 3 ClickSelect Existing Mosaic File 4 Select a mosaic file 5 Click Close Ro step in your project See Mosaicking Images Automatically on page 113 or Mosaicking Images Manually on page 115 112 PCI Geomatics Mosaicking Images Automatically Editing the Mosaic Extents After dragging the frame to determine the mosaic area the dimensions of the frame are displayed under Mosaic Extents To edit the dimensions you can place the pointer over the side or corner of the frame and move it to change its size and shape click UL amp LR Corner in the list under Mosaic Extents and then type new x and y coordinates for the upper left and lower right corners of the frame click UL amp Size in the list under Mosaic Extents Type new x and y coordinates for the upper left corner of the frame Type the number of pixels in X Size and the number of lines in Y Size to specify the size of the frame click Center amp Size in the list under Mosaic Extents Type new x and y coordinates for the center of the frame Type the number of pixels in X Size and the number
51. model The following conditions may help you to identify such problems One or More GCPs or Tie Points with Very High Residual Errors A ground control point GCP or tie point with a very high residual error compared to the others in the Residual Errors report may indicate an error in the original GCP coordinate a typographical mistake or an error in the position of the GCP or tie point on the raw image These points are called outliers To correct an outlier Verify that the feature that you picked in the raw image corresponds to the one from your source Verify that the typed ground coordinate matches the coordinate listed in your source Confirm that the ground coordinate that you collected in the raw image is consistent with the coordinate that you selected from the vector or the geocoded image Verify that the projection and datum for the ground coordinate are correct OrthoEngine User s Guide 57 Chapter 5 Collecting Control Points and Computing the Math Models If all else fails delete the point or change it to a Check Point For information about Check Points see Troubleshooting the Math Model Solution on page 56 Overall High Residual Errors If the residual errors for all the GCPs and or tie points in general are high it may indicate a poor model solution Poor model solutions can be the result of inaccurate GCPs errors in the projection or datum inadequate distribution of the ground co
52. mosaic For more information see Understanding Color Balancing on page 117 In the Color Balance list select a method None if you do not want to apply color balancing Entire Image to use the histogram of each entire image to compute the color balancing This method is recommended for images with low overlap or for images with systematic effects such as when images are bright at the top and dark at the bottom Overlap Area to use only the pixels where the images overlap to compute the color balancing This method is recommended for most images Cutlines are drawn in areas where the seams are the least visible based on the radiometric values of the overlapping images For more information see Understanding Cutlines on page 117 In Cutline Selection Method select Min Difference to place the cutline in areas where there is the least amount of difference in gray values between the images Min Relative Difference to place the cutline in areas where there is the least amount of difference in gradient values between the images Edge features to use a combination of Min Difference and Min Relative Difference to determine the optimum location for the cutline Use Entire Image to mosaic images that do not overlap OrthoEngine uses the four corner coordinates of the images as the cutlines to avoid gaps between the images Under Processing Start Time click Start Now or Start at hh mm and set the time when you want th
53. not know what the background value is click DEM Info The DEM INFO window displays the three lowest and three highest values The background value is usually a dramatically different value such as 150 or 999 999 98 PCI Geomatics Orthorectifying Your Images 11 12 13 14 15 16 The elevation reference in the DEM must match the elevation reference of the imagery that you want to orthorectify Most math models are based on Mean Sea Level However two math models are based on an ellipsoid the RADARSAT Specific Model and the Rational Functions model when it is used with the IKONOS GEO Ortho Kit product If you are using one of these models and your DEM is not based on an ellipsoid see Converting the DEM Datum on page 126 If you need to convert the values in the DEM type the scale value in the Elevation Scale box For more information see Understanding Elevation Scale and Offset on page 100 If you need to compensate for a difference in elevation type the offset value in the Elevation Offset box For more information see Understanding Elevation Scale and Offset on page 100 For Elevation Unit click Meter or Feet to identify the unit that the elevation numbers in your DEM represent If you want to use the same options set under DEM for all your images select Apply DEM options to all images Once you select Apply DEM options to all images the DEM options are set for all the images Cleari
54. on one of the three basic types azimuthal conical and cylindrical For example the Transverse Mercator Projection is a variation of the cylindrical projection A datum is a mathematical surface used to make geographic computations An ellipsoid approximates the size and shape of all or part of the earth The datum includes parameters to define the size and 12 PCI Geomatics Setting the Projection shape of the ellipsoid used and its position relative to the center of the earth Geographic coordinate systems use different datums to calculate positions on the earth If you compare the same point using two different datums or projections the coordinates of the point will be different Referencing a project s coordinates to the wrong datum or using the wrong projection may result in features being offset by significant distances Different projections and datums introduce different distortions or warping into the image You should choose the projection and datum that will give you the results that you expect for your project If you are using data from multiple projections OrthoEngine can only re project the coordinates correctly if the projection and datum are set properly we Reference For more information read lliffe J C Datums and Map Projections for Remote Sensing GIS and Surveying Whittles Publishing Caithness Scotland 2000 Kennedy Melita Understanding Map Projections Environmental Systems Research Ins
55. on screen compared with the time that it will take to build the overviews To enable or disable the overviews 1 Inthe main menu click Options 2 Click Build Overview 3 Click Build Overview to create overviews No Overview to disable overview creation Exporting the Math Model You can export the math model solution as a segment in the PCIDSK file containing the raw image You can use this feature to re establish OrthoEngine User s Guide 129 Chapter 10 Additional Features the computed math model in a future project or use it in projects outside OrthoEngine To export the math model solution 1 Inthe main menu click Options 2 Click Export 3 Click Model 4 Select file to export 5 In the Name box type the label of the segment 6 In the Description box type a description for the segment 7 Click Export Exporting the Ground Control Points You can export the GCP coordinates to a text file or as a segment in the PCIDSK file containing the raw image To export the GCPs to a text file 1 Inthe main menu click Options 2 Click Export 3 Click GCPs 4 Select file to export 5 In Segment Information click Save to text file 6 Click Export 7 In GCP Output File type the path and filename with the extension txt for the file or click Select to select a location 10 11 To In the Format Description type the format of the command string used to express the co
56. or equal to the value set in Value to Replace gt to replace all values greater than the value set in Value to Replace 6 In Value to Replace type the number that you want to change 7 In Skip Value type the number in the selected range that you do not want replaced 8 In New Value type the number that you want to use instead 9 In the New Value list select Replace to replace all the image pixel values equal to the Value to Replace by the New Value Add to add the New Value to all the image pixel values equal to the Value to Replace Subtract to subtract the New Value from all the image pixel values selected using the Value to Replace OrthoEngine User s Guide 125 Chapter 10 Additional Features Multiply to multiply by the New Value all the image pixel values selected using the Value to Replace Divide to divide by the New Value all the image pixel values selected using the Value to Replace 10 Click Replace Photo Value Converting the DEM Datum The elevation reference in the digital elevation model DEM must match the elevation reference of the imagery that you want to orthorectify Elevation values can be referenced to a number of different surfaces but for mapping operations you usually use elevations above Mean Sea Level MSL which is based on the geoid For most math models the model is based on ground control points that are also based on the geoid Two math models are bas
57. or moved to another location If you changed the image s location you can re establish the connection between the project and an Offline image with Rename Image Photo or Sync Image Photo from the Utilities menu Renaming Images You can also use the Rename Image Photo feature to change the Photo ID of an image To rename an image from the project 1 In the main menu click Utilities 2 Click Rename Image Photos 3 Select Uncorrected Photos to select a raw image Ortho Photos to select an orthorectified image or geometrically corrected image Epipolar Photos to select an epipolar pair 4 Click an image from the list 5 Youcan Typea new label for the image in the Photo ID box Typea new path in the Photo File box Click Browse to select the file 6 Click Close 124 PCI Geomatics Replacing Image Pixel Values Synchronizing the Images The Sync Image Photos feature refreshes the link between the images and the project as long as the paths remains the same For example if your images are stored on multiple CDs instead of on the disk some of your images will appear as Offline when the corresponding CD is not available Using Sync Image Photos re establishes the link To re connect Offline images 1 Open a project 2 Inthe main menu click Utilities 3 Click Syne Image Photos 4 Click Yes to re establish the link 2 s Tip If the images do not change from Offline to Online the
58. page 97 Geometrically correct images Geometric Correction is the process of using ground control points GCPs to calculate a simple math model that will warp the raw image to fit the ground coordinates For more information see Understanding Geometric Correction on page 100 Mosaic Mosaicking is the process of joining corrected images into a seamless image map For more information see Understanding Mosaicking on page 111 Generate Digital Elevation Models DEMs A digital elevation model is a digital file of terrain elevations For more information see Understanding Digital Elevation Models on page 63 Edit features in three dimensions 3 D You can view and extract features in 3 D from a pair of stereo images using anaglyph or shutter displays For more information see Understanding 3 D Stereo Viewing and Editing on page 81 Decide which images you want to use Depending on what you decided in step 1 do you need aerial photographs or satellite images If you are going to use aerial photographs you need to decide at what altitude the aircraft should fly what camera type will be used and plan the flight lines If you are going to use satellite imagery you must decide from which sensor you want to acquire your imagery Collect control information You can obtain ground control points from sources such as GPS data surveys scanned maps and vector databases You can use existing DEMs that cover your a
59. previously set for the photograph if any are displayed under Exterior Orientation Parameters Under Exterior Orientation Parameters type the exterior orientation parameters of the selected photograph into the X Y Z Omega Phi and Kappa boxes On the Input GPS INS Data Manually window in the boxes beside the X Y Z Omega Phi and Kappa boxes type the estimated error for the orientation parameters if available The data set or GPS INS sensors usually contain the estimated accuracies The estimated error values are used to automatically weight the exterior orientation data with GCPs and tie points during the computation of the math model The units are the same as the input file OrthoEngine User s Guide 29 Chapter 4 Setting Up Camera Calibration and Aerial Photographs After typing in the Omega Phi and Kappa values you can use the Unit options to convert the values between Degrees and Radians for comparison OrthoEngine stores these values in degrees internally 8 Click Accept 9 Repeat steps 5 to 7 until all the photographs are set 10 Click Close Changing Photo Orientation Change Photo Orientation does not apply to digital or video images since they do not contain data strips or fiducial marks Although it is not necessary to position the aerial photographs in a specific manner you may find it easier to work with your photographs when they appear on the screen in a particular fashion
60. project 1 Onthe OrthoEngine window in the File menu click New 2 Onthe Project Information window in the Filename box type a file name for your project This will be the name used when you save your project 3 Inthe Name box type a name that you want to appear on the title bar of the OrthoEngine window 4 Inthe Description box type a description of the project that will help you to identify its contents 5 Under Math Modelling Method click Satellite Orbital Modelling For IKONOS images see Using the Right Math Model with IKONOS Data on page 6 6 Under Options select the sensor type corresponding to the images that you are using in your project Click Toutin s Model when you are using high resolution optical or radar satellite sensors such as LANDSAT RADARSAT SPOT or IKONOS e Click ASAR RADARSAT Specific Model when you want to use the additional parameters in RADARSAT s orbit data to diminish amount of ground control points GCPs required The extra parameters maintain the positional accuracy and high levels of detail in the model but the number of GCPs needed is reduced to few or none This math model does not use tie points since each scene is computed using the GCPs of that scene only Click Low Resolution when you use low resolution sensors such as AVHRR 7 Click Accept HRe step in your project See Setting the Projection on page 13 10 PCI Geomatics Starting a Project
61. sensor 6 Under Orbit and Sensor Information enter the orbit information and the values specific to the sensor obtained from the sensor s technical manual 7 Under Image Information enter the image s information including the image resolution the latitude the longitude and the corresponding ellipsoid of the scene center 8 Click Start Orbit Calculation He step in your project See Collecting Control Points and Computing the Math Models on page 33 Importing Satellite Data from a PCIDSK File If you have satellite imagery and orbit ephemeris data that is saved into a PCIDSK file you can add the data into your project To import satellite data from a PCIDSK file 1 On the OrthoEngine window in the Processing Step list select Data Input 2 Click c3 the Read PCIDSK File icon 3 In the Database File Selection window select the image that you want to import into your project Click Open fex step in your project See Collecting Control Points and Computing the Math Models on page 33 Opening Images To view an image in your project 1 On the OrthoEngine window in the Processing Step list select GCP Collection al 2 Click pay the Open new or existing photo icon 3 In the Open Photo window click an image OrthoEngine User s Guide 17 Chapter 3 Importing and Viewing Images 4 Click Open to open the image and select the bands to display Quick Open to open an i
62. sequence that the original vector was created 6 Click Insert Vertex or press INSERT to accept the additions Deleting a Vertex To delete a vertex 1 Move the pointer to the 3 D viewer and press ESC to switch to the stereo cursor 2 Click the vertex that you want to remove 3 Click Delete Vertex or press D The vertex is deleted the vector adjusts automatically and the action is accepted 4 To delete another vertex you must repeat the steps OrthoEngine User s Guide 91 Chapter 7 Editing Features in 3 D Stereo Deleting a Line or Polygon To delete a line or polygon 1 Move the pointer to the 3 D viewer and press ESC to switch to the stereo cursor 2 Select a vector For information about how to select a vector see Using the Vector Editing Tools on page 90 3 Click Delete Line or press DELETE The vector is deleted and the action is accepted 4 To delete another vector you must repeat the steps Moving a Vertex or a Point To move a vertex 1 Move the pointer to the 3 D viewer and press ESC to switch to the stereo cursor 2 Click Move or press B 3 Position the stereo cursor precisely on the location where you want to place the vertex Adjust the position not only in x and y but also in z You can also use Snap to Vertex or Snap to Line to position the cursor For more information see Using Snap to Vertex on page 90 and Using Snap to Line on page 90 4
63. solution 27 vectors 122 video images 15 Import amp Build DEM 64 IMU See Inertial Measurement Unit Inertial Measurement Unit 27 Infrequency 121 Initialization 49 INITIALIZE init string 61 Input Exterior Orientation Data Manually 29 Input GPS INS Data Manually 29 Input Vector Layer 66 Input window 80 96 insert vertex 90 interior orientation 21 Interleave 118 Interpolate 78 Interpolate Holes 64 150 PCI Geomatics IRS DEM from stereo pairs 69 intro to OrthoEngine 1 minimum number of GCPs 34 supported formats 18 understanding Satellite Orbital Math Model 5 J JERS intro to OrthoEngine 1 minimum number of GCPs 34 supported formats 18 understanding Satellite Orbital Math Model 5 joining image tiles 126 K kappa 27 55 rotate 27 29 Kernel File 106 L Lakes 78 LANDSAT intro to OrthoEngine 1 minimum number of GCPs 34 selecting NLAPS CD Format 16 supported formats 18 understanding Satellite Orbital Math Model 5 Last Value 73 Layer add lines 88 add points 88 add polygons 89 change order 87 change projection 86 create layer for 3 D vectors 85 delete 94 import 87 save 93 show hide 87 layout of string 50 LF 60 LGSOWG JERS1 18 LGWOWG SPOT Canadian format 19 Line Drawing Width 76 Line Spacing 14 Linear 121 Lines 66 88 96 Load vectors 122 Low Resolution 10 M Manual Mosaicking 115 manually collect GCPs 36 manually collect tie point 52 map north 27 Map Tie down 46 MAP ORIENTED produ
64. the input image channel that you want to use for the image correlation Choose the channel that has the same color band or wavelength as the image chip so the features on the ground will look the same in the two images Select Apply to all Photos if you want to use the same channel for all of the images To select a different channel for each image click the image under Photos and click the number of the Match Channel that you want to use Use a channel other than blue because the blue band tends to saturate so it is not as sharp as some of the other bands 6 Click Match Chips A progress indicator displays the percentage of the process completed The matches between the chips and the images are displayed in the Chip ID and Photo ID columns under Chips 7 Toreject matches identified in the Use as GCP column click in the Use as GCP column to clear the matches of your choice You can also click Use all to select all the matches or click None to clear all of them Click Show Distribution to view how the selected GCPs are dispersed over the images The image footprints appear as gray lines and the GCPs appear as blue crosshairs For more information about the matching process see Changing the Correlation Parameters for Automatic GCP Collection from a Chip Database on page 44 8 Clickthe Use as GCPs button to accept the matches identified in the Use as GCP column as GCPs in your project 9 Click Print to File if you want to sa
65. the new location of the point and click Use Point 3 Click Accept 4 Verify the results in the table If you are not satisfied select the same point in the table on the Residual Errors window click Edit Point and repeat the process 5 Ifyou decide that the point is still not acceptable click Delete Point to remove the point from the project Change to Check Point to remove the point from the math model calculations but keep the point in the project OrthoEngine calculates the difference between the Check Point s position and the position determined by the model and includes the error in the Residual Report Therefore the Check Points provide an independent accuracy assessment of the math model le Press SHIFT and click to select a range of neighboring points or press CTRL and click separate points He step in your project See Understanding Digital Elevation Models on page 63 Understanding 3 D Stereo Viewing and Editing on page 81 or Orthorectifying Your Images on page 98 OrthoEngine User s Guide 59 Chapter 5 Collecting Control Points and Computing the Math Models Defining the Tablet Format Strings Tablets are usually attached to RS 232C ports terminal ports Like other RS 232C devices you must configure the connection between the tablet and the port correctly Most tablets come with jumpers or toggle switches that provide a range of possible baud rates parity data bit size and s
66. to Process The status displayed beside the image explains what happens after you process the images Delete Existing File The previous version of the corrected image will be replaced by the new one Create New File The corrected image will be saved on the disk Status descriptions for images under Uncorrected Photo or Uncorrected Image No model computed The math model was not computed and the image cannot be processed see Collecting Control Points and Computing the Math Models on page 33 Project Changed model stale The math model may be out of date To recompute the math model see Performing the Bundle Adjustment for Rigorous Math Models on page 55 Model up to date The math model is current and can be used to process the image Status descriptions for images under Ortho Photo or Corrected Image No ortho generated A corrected version of the image was not found on the disk Model updated since last ortho generated A corrected version of the image was found on the disk but it does not match the current math model Ortho matches computed model A previous version of the corrected image was found on the disk and the same math model was used for both File exists Will DELETE existing file The previous version of the corrected image will be replaced by the new one Currently Off line New file will be created The image was previously processed but the file was not found
67. use it to quickly position new vertices or to move existing vertices on the same layer o s Tip When you are working with the stereo cursor in the 3 D viewer you can press C to activate and deactivate Snap to Line For more shortcuts see Using Shortcuts in the 3 D Viewer on page 94 To snap to a line 1 Click Snap to Line 2 Position the stereo cursor close to an existing vector and click The cursor aligns with the vector nearest to where you clicked 3 Click Snap to Line to turn off the feature You can turn on or off Snap to Line at any time while you are collecting or editing vertices Using the Vector Editing Tools You can use the vector editing tools to move change and delete the three dimensional 3 D vectors 90 PCI Geomatics Using the Vector Editing Tools To select a vector 1 Move the pointer to the 3 D viewer and press ESC to switch to the stereo cursor 2 Click on the vector that you want to select or click the vector in the Attribute table The vector is highlighted and the stereo cursor is placed on the nearest vertex Only one vector can be selected at a time 3 Use the Vector Editing tools Insert Vertex Delete Vertex Delete Line Move Undo 4 Click Accept or press ENTER to accept the change Inserting a Vertex To draw a line or a polygon you click a series of vertices to form the vector The first vertex is the start point of the vector and the la
68. 116 automatic 113 blending the seams 117 collecting cutlines 115 color balancing 116 117 default output format 128 defining Mosaic Area 112 DEM 119 Double Window 118 images with Background Value other than zero 113 Interleave 118 manual 115 Mosaic Area 112 Mosaic Image Reference 118 None Mosaic Only 112 Overlay 118 Reapply Mosaicking 118 understanding 111 understanding color balancing 117 understanding cutlines 117 move vectors 90 N NAME tablet name 61 Natural Neighbor Interpolation 68 navigating the 3 D viewer 84 navigation solution 10 Nearest Neighbor Interpolation 105 New Aerial Photograph project 9 Mosaic Only project 12 Polynomial project 11 Rational Functions project 11 Satellite project 10 Thin Plate Spline project 12 New chip 137 New chip database name box Chip Manager 139 New Photo 15 NITF file 11 NITF format 18 19 NLAPS LANDSAT 5 19 No Data See Background Value No of Coefficients 36 38 39 41 No of Iterations 68 No of Tie Points per Area 53 Noise 79 Noise Removal 77 nominal scale 24 None Mosaic Only 112 152 PCI Geomatics non symmetric distortion See Decentering Distortion Normalization 114 normalized residual errors 59 north 27 number of GCPs 34 Number of Looks for Radar Enhanced Frost 109 for Radar Enhanced Lee 110 for Radar Gamma Filter 107 for Radar Kuan 109 number of tie points per area 53 O Offline reconnecting 124 omega 27 55 open an existing chip databas
69. 139 Chapter 11 Creating a Chip Database 3 Select a chip database and click Open 4 Click Yes to delete the database Deleting a Chip from the Database To delete a chip from a chip database 1 Open a database For more information see Opening an Existing Chip Database on page 136 2 Select the chip that you want to delete To search the database see Searching the Chip Database on page 139 3 Atthe bottom ofthe PCI ImageChipsManager window click Delete chip The chip that appears in the chip viewer is deleted 4 Click Yes to delete the chip Defragmenting a Chip Database As chips are deleted from the chip database the gaps in the database remain Defragmenting the chip database reduces the amount of disk space it occupies To defragment the chip database 1 Open the database that you want to defragment For more information see Opening an Existing Chip Database on page 136 2 Inthe main menu click Utilities 3 Click Pack 4 Click Yes to defragment the database Generating Reports The Current Chip report produces information about the chip displayed in the PCI ImageChipsManager window The report provides information such as the Chip ID sensor type view angle acquisition date scene ID general ID GCP location and elevation chip size resolution number of image channels data type of the image channels the source file from which the chip is extracted and so on The Summary r
70. 3 If you have several images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The Tie Point Collection window collects and displays the tie points from the image in the Working viewer only Click the Reference button to switch the viewer to Working You can collect the same tie point in each image by clicking Reference in a viewer collecting the tie point and then repeating the process for each image 52 PCI Geomatics Collecting Tie Points Automatically To collect tie points manually l On the OrthoEngine window in the Processing Step list select GCP TP Collection Ta Click pui the Open new or existing photo icon to open two or more images For information how to open an image see Opening Images on page 17 On the OrthoEngine window click E the Manually collect tie points icon On the GCP Collection window the Point ID is generated automatically You can type a new label in the Point ID box however all points ground control points check points tie points and elevation match points in the image must have unique labels You can select Auto Locate and or Bundle Update to aid with collection For more information see Using Auto Locate on page 35 and Using Bundle Update on page 36 Ata zoom level where you can see the detail in the raw image position the cursor precisely on the feature that you will use as a tie point and the
71. 32 767 The term 16 Bit determines the range of values by calculating 2 to the sixteenth power 216 which equals 65 536 Signed means it uses both positive and negative integers therefore the range is set from 32 767 to 32 767 16 Bit Unsigned to set the range of pixel values in the images from 0 to 65 535 The range of values is the same as explained for 16 Bit Signed however Unsigned means it uses only positive integers therefore the range is set from 0 to 65 535 32 Bit Real to set the range of pixel values that includes decimals and positive and negative values The term 32 Bit Real is a range of real numbers that is expressed as 1 2E 38 to 3 4E 38 This option takes the most amount of disk space Understanding When To Build Overviews Overviews are created when you orthorectify geometrically correct or mosaic your images Although overviews quicken the display of your images on your screen they do add processing time when they are created Therefore you need to decide which will benefit you the most viewing the images faster or processing the images faster For example If you are orthorectifying 200 small images you may decide not to create overviews since small images take very little time to display on screen and building overviews will add significantly to the processing time If you are orthorectifying two large IKONOS scenes you may decide to create overviews since large images take longer to display
72. 36 38 39 41 polynomial transformations 8 POS EO 27 position of sensor 55 position of the camera 27 position the aerial photographs 30 Preferences Chip Manager 141 Principal Point Offset 22 24 Processing Start Time 30 54 produce a report Chip Manager 140 Project Information for Aerial Photography projects 9 for Mosaic Only project 12 for Polynomial projects 11 for Rational Functions projects 11 for Satellite Orbital projects 10 for Thin Plate Spline 12 project information report 132 Project Report 132 projection 12 13 for 3 D feature extraction 86 puck 45 Q Quick Open 18 Quick Open amp Close 18 QUICKBIRD DEM from stereo pairs 69 intro to OrthoEngine 1 joining tiles 126 minimum number of GCPs 34 stitching 126 supported formats 19 understanding Rational Functions Math Model 7 understanding Satellite Orbital Math Model 5 R RADAR supported formats 19 Radar Enhanced Frost 108 Radar Enhanced Lee 110 Radar Gamma Filter 107 Radar Kuan 109 RADARSAT converting the DEM datum 126 DEM from stereo pairs 69 intro to OrthoEngine 1 minimum number of GCPs 34 RADARSAT Specific Model 10 SAR 19 selecting left and right images 70 setting the GCP elevation datum 128 supported formats 19 understanding Satellite Orbital Math Model 5 using Pixel Sampling 72 Web tool for selecting stereo pairs 69 Radial Distortion 22 radial distortion See Principal Point Offset Radial Lens Distortion 22 24 Radian 28 Rapid Positioning Capability
73. 6 OrthoEngine User s Guide 47 Chapter 5 Collecting Control Points and Computing the Math Models 5 On the tablet position the crosshairs of the puck precisely on the feature on the paper map that you will use as a GCP and press the button to select the point If you selected Grid Pinning when you set up the tablet you will have to select the four points around the feature to anchor the reference frame For more information about Grid Pinning see Using a Tablet to Collect Ground Control Points on page 45 The geocoded Easting and Northing coordinates transfer to the GCP Collection window 6 Onthe GCP Collection window under Georeferenced Position in the Elev box type the elevation of the GCP or you can use a digital elevation model DEM to determine the elevation of your GCPs see Using a Digital Elevation Model to Set Ground Control Point Elevation on page 51 7 In the boxes beside the Elev box the Easting box and the Northing box type the estimated error for each Georeferenced Position UTM 17 U E008 Elevation gt Elev 2000 m Easting 0 5 E Northing gt 0 5 N Longitude gt Lom Lat Latitude Accept Delete New Point 8 At a zoom level where you can see the detail in the raw image position the cursor precisely on the same feature that you selected on the paper map and click Use Point The pixel and line coordinates from the raw image appear in the GCP C
74. 6 Gaussian Filter ooo A pe A As 106 User Defined FIler A O RERCREM ERE PRCEEM GERE NO NEBRU tereeaduassdesuagnasbesdapusestas ERES 106 Radar Gamma cR es 107 Radar Enhanced Frost Filters ci tme deba TR ERR ERE o met toin ii 108 Radar Kuan Filter ea 109 Radar Enhanced Lee Filter ee ti Mr NEED E RET ia 110 Chapter 9 MOSAICKING YOUR IMAGES Understanding MOSAIEKING RR 111 Defining a Mosaic Area icon dao soucopeelsoeeseraastebaunes mabe citada 112 Editing the Mosaic EXtenls usin Haniel ein ele e en ie o Pg ee ee ee 113 Mosaicking Images with a Background Value Other Than Zero ssssssssssseeeseeeene nennen enne nenne enne ne nnn nennen nene 113 Mosaicking Images Automatically e dive 113 Mosaicking Images Manually cooooori e 115 Adding an Image to the Mosaic t t bene eevee e E iden ieee dee eoe deg eaten A ey Ree Lee e e ve re 115 Collecting the Cutline XD PES 115 vi Adjusting the Color Balance ia DIL atetaaita eds 116 Adding h mage to he Mosalc Area t a etsi metet tn diete mue 116 Blending the Seams annir or 117 B aere ate ae AE a E AE STEET AA E E EE 117 Understanding Color Balancing ine anna 117 Changing the Layout in the Manual Mosaicking Window
75. 6 pixels by 256 lines GeoTIFF 512 Tiled to save the image in the GeoTIFF format stored as tiles measuring 512 pixels by 512 lines GeoTIFF 1024 Tiled to save the image in the GeoTIFF format stored as tiles measuring 1024 pixels by 1024 lines TIFF World to create a single file in the TIFF World format 128 PCI Geomatics Setting the Channel Type for Your Output Image TIFF World 256 Tiled to save the image in the TIFF World format stored as tiles measuring 256 pixels by 256 lines TIFF World 512 Tiled to save the image in the TIFF World format stored as tiles measuring 512 pixels by 512 lines TIFF World 1024 Tiled to save the image in the TIFF World format stored as tiles measuring 1024 pixels by 1024 lines Setting the Channel Type for Your Output Image To set the channel type for the orthorectified or geometrically corrected images 1 Inthe main menu click Options 2 Click Ortho Channel Type 3 Click Same As Input to set the range of pixel values according to the values in the raw images 8 Bit Unsigned to set the range of pixel values in the images from 0 to 255 The term 8 Bit determines the range of values by calculating 2 to the eighth power 25 which equals 256 Unsigned means it uses only positive integers therefore the range is set from 0 to 255 This option takes the least amount of disk space 16 Bit Signed to set the range of pixel values in the images from 32 767 to
76. 64 0614 Direct to our main office By e mail support pcigeomatics com license pcigeomatics com Training course information education pcigeomatics com Suggestions for future versions of PCI Geomatics products ideas pcigeomatics com On the Web http www support support html By fax Fax 1 905 764 9604 attention support By mail PCI Geomatics 50 West Wilmot Street Richmond Hill Ontario Canada L4B 1M5 Attention Technical Support PCI Geomatics Understanding the Math Models A math model is a mathematical relationship used to correlate the pixels of an image to correct locations on the ground accounting for known distortions The math model that you choose directly impacts the outcome of your project To achieve the results that you are looking for you need to understand what the math models do what the math models require to produce an acceptable solution and which math model to use with your project You can use one of five math models Aerial Photography Satellite Orbital Rational Functions Polynomial Thin Plate Spline Understanding the Aerial Photography Math Model The Aerial Photography Math Model is a rigorous model based on the geometry ofa frame camera This model can compensate for the effects of varying terrain and for the distortions inherent to the camera such a Ne A CHAPTER BN 7 4 as the curvature of the lens the focal length the perspective e
77. 7 Rational Functions Math Model 6 equations 7 minimum number of GCPs 34 Starting a project 11 understanding solution 56 Read CD ROM 15 Read GCPs from Text File 49 Read Generic Image File 17 Read PCIDSK File 17 Read satellite images 15 16 17 Read Tape 16 Reapply Mosaicking 118 recompute model 132 rectangular sensor cells 24 reduce disk space used Chip Manager 140 154 PCI Geomatics reducing eyestrain 82 83 Re enhance 121 reference frame 23 47 reference frame for tablet 45 regenerating the mosaic 118 Region of Interest ROI 43 relating images together See tie point Reload 122 remove gaps in chip database 140 remove image from project 124 Rename Image 124 Rename images 124 replace elevation values under mask 76 replace pixel values 125 Reports Chip Manager 140 reprojecting DEM 79 reprojecting images 69 Resampling 64 104 Residual Errors 56 Residual Report 58 editing points 59 resolution 14 73 Resolution of DEM 67 Restore Defaults for chip search 43 RGB color bands 43 RGB color bands Chip Manager 137 RGB Mapper 123 Ridges 2D 66 rigorous math model 5 55 Orthorectification 98 ROI 43 Root 121 rotate images 29 30 rotate kappa 27 29 RPC 7 rules for format strings 60 S Sampling Interval 102 SAR 19 minimum number of GCPs 34 SAR Type 16 Satellite Orbital Math Model 5 minimum number of GCPs 34 Starting a project 10 understanding solution 55 satellite sensors supported 1 18 save a layer 93 sa
78. 8 per image 10 to 12 per image ASAR EROS RADARSAT with the GCPs improve accuracy with 1 RADARSAT specific model optional or 2 GCPs Rational Functions If Computed from GCPs 5 per 19 per image image If Extracted from Image File none optional for IKONOS Ortho Kit improve accuracy with 1 or more GCPs Thin Plate Spline 3 per image more than the minimum will average out errors introduced by inaccurate GCPs or terrain variations 34 PCI Geomatics Determining the Right Combination of Ground Control Points and Tie Points for the Satellite Math Model Table 1 Minimum Number of GCPs Math Model Minimum Recommended GCPs s _ __ lt amp gt gt e si cH Do c E eee Polynomial First order 4 per image more than the minimum will average out errors Second order 7 per image introduced by inaccurate Third order 11 per GCPs image Fourth order 16 per image Fifth order 22 per image Depends on the number of coefficients that you want to use see Understanding the Rational Functions Math Model on page 6 Determining the Right Combination of Ground Control Points and Tie Points for the Satellite Math Model When the viewing angle difference between the images is less than 7 degrees meaning a base to height B H ratio less than 0 1 to 0 15 you should collect the minimum required ground control poi
79. 95 2003 LizardTech Inc All rights reserved UNIX is a registered trademark of The Open Group Copyright c 2002 Mapping Science Inc GeoJP2 is a trademark of Mapping Science Inc The GeoJP2 format is the intellectual property of Mapping Science Inc All other trademarks and registered trademarks are the property of their respective owners d 7 Uu Table of Contents ss NC AQ LN Chapter 1 USING ORTHOENGINE Introducing Geomatica OrthoErigine container portta ka REEL optar poe er dag een RA Iesu tege detienen 1 Getting Started PE o ios 2 Working with OrthoEnglle s 1 ie Net IR nd oe See ere Ete Rd Ee S IER RERO re Geter do eec rate tated eec e etn eene redo 2 How To Contact Us P 4 Chapter 2 STARTING YOUR PROJECT AND SELECTING A MATH MODEL Understanding the Math Models 2 aria os ias ta ai ads 5 Understanding the Aerial Photography Math Modeel sse nennen enn r nn rana nan rr nen n aran nnn nn nnns ener nne 5 Understanding Satellite Orbital Modelling sese nor rcnnnn rre rra 5 Using the Right Math Model with IKONOS Data coooooccococcnoccccnoonccononcnononcnonancnn non cnn nan n nr nn rre Rene nera enr ne nnns senten enne nnne 6 Understanding the Rational Functions Math Model c cccccceceececeeeeeee cece ceeaeceeeeeeceeae cnn nan nn nn nan nn nn nn inn r RR nn nn nn nn tenis si e
80. CPs You can import or export ground control points GCPs to a text file Each line in the text file contains the data for one GCP The line is divided into fields separated by spaces tabs and or commas Each field contains a piece of information about the GCP When you import or export the GCPs to a text file you must identify what the fields contain and in what order they appear A Format Description is a string representing the order and the contents of the fields Character descriptions I the GCP s identification number X the geocoded X coordinate Y the geocoded Y coordinate P the pixel location of the GCP on the uncorrected image file L the line location of the GCP on the uncorrected image file E the elevation of the GCP D data to be ignored For example the string IXYE represents the layout where I is the GCP s identification X and Y are the GCP s geocoded x and y coordinates and E is the GCP s elevation OrthoEngine User s Guide 133 Chapter 10 Additional Features The line in the text file and the Format Description must match Lines that do not match the Format Description are ignored Fields can contain text alphanumeric values integers decimals or exponential values for example 1 234 E05 Latitude and Longitude values must appear in decimal degrees 123 5 rather than DMS form 123 30 00 To include a phrase in a field place the phrase in double quotes If the field contain
81. Click Accept Changing the Colors of the Cursors To change the color of the cursor in the source image viewer 1 Inthe main menu click Preferences and click Colors 2 Inthe Chip Cursor Color list select the color that you want 3 Click Close To change the color of the cursor in the chip viewer 1 Inthe main menu click Preferences and click Colors 2 Inthe Chip GCP Color list select the color that you want 3 Click Close To mix your own color In the main menu click Preferences and click Colors In the Chip Cursor Color list or Chip GCP Color list click Mix Color Move the sliders for Red Green and Blue or type the color values that you want in the corresponding boxes until you have the desired color Click Close OrthoEngine User s Guide 141 Chapter 11 Creating a Chip Database 142 PCI Geomatics Index Numerics 16 Bit Signed 112 129 16 Bit Unsigned 112 129 32 Bit Real 112 129 3 D Feature Extraction add lines 88 add points 88 add polygons 89 aligning the images 85 Anaglyph technology 82 change color of vectors 87 change order of layers 87 change projection 86 change type of vectors 88 change visibility of layers 87 completing the Attribute table 93 create a layer 85 delete a layer 94 delete line or polygon 92 delete vertex 91 designing the Attribute table 92 extracting lines from DEM 96 extracting points from DEM 95 import layers 87 insert vertex 91 metada
82. Collecting Ground Control Points from a Geocoded Image the elevation of your GCPs see Using a Digital Elevation Model to Set Ground Control Point Elevation on page 51 9 Inthe Easting box and the Northing box type the ground coordinate ofthe GCP in the projection shown beside Georeferenced Position Georeferenced Position UTM 17 U E008 Elevation 3 Eev 2000 m Easting 0 5 E Northing 0 5 N Longitude Leng Lat Latitude Accept Delete New Point 10 In the boxes beside the Elev box the Easting box and the Northing box type the estimated error for each 11 At a zoom level where you can see the detail in the raw image position the cursor precisely on the feature that you will use as a GCP and then click Use Point The pixel and line coordinates from the raw image appear in the GCP Collection window under Photo Position or Image Position 12 Click Accept The GCP is added to the Accepted Points table 2 s Tip You can edit the error estimate in the boxes under Image Position to correspond to your ability to precisely identify a feature in the image For example if you use coarse imagery you can probably only measure to the closest pixel If you use imagery that was compressed or poorly scanned you may only be able to measure to the closest two pixels Even if you identify a GCP to the closest pixel the coordinate may only be accurate to so many meters
83. Distortion values for digital cameras Since the manufacturing of digital cameras and their lenses is often not as precise as that for high end photogrammetric cameras the Decentering Distortion tends to be higher Defining Photo Scale Photo Scale is the ratio ofthe size ofthe objects in the image to the size of the objects on the ground This parameter is optional except when you want to import GPS INS observations and use them during the automatic tie point measurements The Photo Scale equation is scale d f D H where d distance in the image D distance on the ground f focal length H height above the ground To enter the Photo Scale see Entering the Camera Calibration Data on page 24 Entering the incorrect Photo Scale may cause the computation of the math model the bundle adjustment to fail Defining Earth Radius The Earth Radius is the radius of curvature of the earth at the location of the project This parameter is optional since aerial photographs usually use a large scale for example 1 8 000 and the error due to the earth s radius is negligible You only need earth radius correction for photographs with a scale over 1 20 000 The Earth Radius equation is radius a 1 e 1 e sin p where mean latitude of the project based on your GCPs a semi major axis from the datum definition b semi minor axis from the datum definition e a b a To enter the Earth Radius see
84. Engine window in the Processing Step list select GCP Collection 2 Click For information how to open an image see Opening Images on page 17 the Open new or existing photo icon to open an image 3 On the OrthoEngine window click 4 the Import GCPs from sz File icon 4 Onthe Read GCPs from Text File window type the path for the PCIDSK file containing the GCPs segment the text file or click Select to select the file The layout of the file is displayed under Example Lines From GCP file 5 Ifnecessary in the Format Description box type the string representing the layout of the file or select a string from the Example OrthoEngine User s Guide 49 Chapter 5 Collecting Control Points and Computing the Math Models Formats list Each character in the string represents a field in the text file For example the string IXYE represents the layout where I is the GCP s identification X and Y are the GCP s geocoded x and y coordinates and E is the GCP s elevation For more information about the strings in the Example Formats list see Understanding Format Descriptions for Text Files Containing GCPs on page 133 6 Click Apply Format Successfully extracted GCPs appear under GCPs Extracted from File The GCPs are displayed as ID pixel location line location x coordinate y coordinate and elevation Fields from the text file without values appear as zero 7 Click View Edit to enter the project
85. Geomatica OrthoEngine User Guide Geomatica Version 9 0 Release date May 2003 2003 PCI Geomatics Enterprises Inc All rights reserved COPYRIGHT NOTICE Software copyrighted c by PCI Geomatics 50 West Wilmot St Richmond Hill Ontario CANADA LAB 1M5 Telephone number 905 764 0614 RESTRICTED RIGHTS Canadian Government Use duplication or disclosure is subject to restrictions as set forth in DSS 9400 18 General Conditions Short Form Licensed Software U S Government Use duplication or disclosure is subject to restrictions as set forth in FAR clause 52 227 19 Commercial Computer Software Restricted Rights and in subparagraph c 1 ii of the Rights in Technical Data and Computer Software Clause at DFARS 52 227 7013 ACE ACE amp Design logo ACE Advanced Cartographic Environment AGROMA EASI PACE EOScape FLY GCPWorks GeoAnalyst GeoGateway ImageWorks OrthoEngine PCI OrthoEngine PCI PCI amp Logo Committed to GeoIntelligence Solutions PCI Author PCI Visual Modeler RADARSOFT RasterWorks and SPANS are registered trademarks of PCI Geomatics Enterprises Inc PCI Geomatics and Geomatica are registered trademarks of PCI Geomatics Enterprises Inc InstallShield is a registered trademark of InstallShield Software Corporation Microsoft is a registered trademark and Windows is a trademark of Microsoft Corporation MrSID is a registered trademark of LizardTech Inc Copyright 19
86. Information table click Show All Changing the Color of the Vectors in a Layer You can select the color of each vector layer Most of the colors are compatible with the anaglyph viewer however some colors are easier to see than others To change the color of a vector layer 1 Click the layer that you want to change 2 Right click in the Color column of the layer 3 Click the color that you want The check mark in the Visible column and the vectors of the layer display the new color OrthoEngine User s Guide 87 Chapter 7 Editing Features in 3 D Stereo Changing the Type of the Layer The Type column in the Vector Layer Information table does not affect the geometry or attributes of the vector layer It simply provides metadata that is saved into the layer To change the Type 1 Click the layer that you want 2 Right click under Type 3 Click the label that you want for the layer DEM Area DEM Building DEM Cliff DEM Contour DEM Gully DEM Points DEM Ridge Planimetric Area Planimetric Line Planimetric Point Adding Points to a Layer You should complete the Attribute table each time you add a points lines or polygons to the layer For more information about the Attribute table see Designing the Attribute Table on page 92 To add points to the selected layer 1 Click New Point 2 Move the mouse pointer to the 3 D viewer and press ESC to switch to the s
87. Mosaic Extents see Editing the Mosaic Extents on page 113 4 Under Mosaic File Information in the Channels list click 8 Bit Unsigned to set the range of pixel values in the images from 0 to 255 The term 8 Bit determines the range of values by calculating 2 to the eighth power 25 which equals 256 Unsigned means it uses only positive integers therefore the range is set from 0 to 255 This option takes the least amount of disk space 16 Bit Signed to set the range of pixel values in the images from 32 767 to 432 767 The term 16 Bit determines the range of values by calculating 2 to the sixteenth power 216 which equals 65 536 Signed means it uses both positive and negative integers therefore the range is set from 32 767 to 32 767 16 Bit Unsigned to set the range of pixel values in the images from 0 to 65 535 The range of values is the same as explained for 16 Bit Signed however Unsigned means it uses only positive integers therefore the range is set from 0 to 65 535 32Bit Realto set the range of pixel values that includes decimals and positive and negative values The term 32 Bit Real is a range of real numbers that is expressed as 1 2E 38 to 3 4E 38 This option takes the most amount of disk space 5 Ifyou selected None Mosaic Only when you set up the project Input Image Background Value becomes available Type the background value of the images that you want to mosaic or click to clear the check mark
88. New 2 On the Project Information window in the Filename box type a file name for your project This will be the name used when you save your project 3 In the Name box type a name that you want to appear on the title bar of the OrthoEngine window 4 In the Description box type a description of the project that will help you to identify its contents 5 Under Math Modelling Method click Thin Plate Spline 6 Click Accept fox step in your project See Setting the Projection on page 13 Starting a Project to Mosaic Existing Georeferenced Images To start the project 1 On the OrthoEngine window in the File menu click New 2 Onthe Project Information window in the Filename box type a file name for your project This will be the name used when you save your project 3 Inthe Name box type a name that you want to appear on the title bar of the OrthoEngine window 4 Inthe Description box type a description of the project that will help you to identify its contents 5 Under Math Modelling Method click None Mosaic Only 6 Click Accept Ro step in your project See Setting the Projection Understanding Projections and Datums A projection represents the earth s irregular three dimensional surface as a flat surface A map projection is used to transform the locations of features on the earth s surface to locations on a two dimensional plane A variety of map projections exist usually based
89. OWG CD provides different levels of processing OrthoEngine supports level 0 1A and 1B CD However we recommend level 1A for highest accuracy OrthoEngine also OrthoEngine User s Guide 19 Chapter 3 Importing and Viewing Images supports old SPOTIMAGE LGSOWG format and the new CAP T format SPOT 5 TIFF The SPOTIMAGE provides different levels of processing OrthoEngine supports level 1A SPOT 5 Dimap format only Quote This is the initial SPOT 5 model support The model will be improved later after testing done by Dr Thierry Toutin at CCRS 20 PCI Geomatics Understanding Camera Calibration Data The camera calibration data is used to identify and correct the distortions introduced into the photograph due to the curvature of the lens the focal length and the perspective effects This information is used to compute the interior orientation which is the relationship between the film and the aircraft Images taken with a standard photogrammetric aerial camera usually come with a report that provides data about the camera If images from a digital or video camera did not come with a camera calibration report the data can be obtained from the camera manufacturer or from the companies that perform the calibration for standard aerial cameras For more information see Defining Focal Length on page 21 Defining Principal Point Offset on page 22 Defining Radial Lens Distortion on page 22 Defining D
90. STREAM stream mode POINT point mode SWITCH switch stream mode BAUD baud rate PARITY parity DATA data bits STOP stop bits Only the TABLET NAME and FORMAT parameters are required Omit any parameters that you do not know Each new tablet definition begins with the TABLET tablet number command where n specifies a unique tablet number Tablet numbers below 10 are reserved for PCI definitions The parameters may be separated by comment lines A comment is indicated by placing a number sign character at the beginning of the line All other parameters may appear in any order following the TABLET parameter The init string point mode switch stream mode and stream mode parameters must be valid command strings The tablet name parameter is the name of the tablet as it would appear in an option menu OrthoEngine User s Guide 61 Chapter 5 Collecting Control Points and Computing the Math Models 62 PCI Geomatics Generating Digital Elevation Models E a Understanding Digital Elevation Models A digital elevation model DEM is a digital file of terrain elevations for ground positions It is a raster representing the elevation of the ground and objects such as buildings and trees with pixel values in the images In most cases the best source of elevation for your project is a good DEM You may want to use a DEM when you are orthorectifying an image to provide geometric correction for relief displacement
91. Select Image to Add and double click the crosshairs of the image that you want or click an image from under Project Image Files Image already included in the Mosaic Area appear in red Selected images appear in cyan Overlapping areas appear in gray If you are adding the first image to the file you can skip Collect Cutline and Color Balancing Follow the steps to add the image to the mosaic and then return to Select Image to Add to work on the remaining images 4 Select Show Mosaic Preview if you want to view the contents of the Mosaic Area rw step in your project Continue with steps in Collecting the Cutline on page 115 Collecting the Cutline For more information about cutlines see Understanding Cutlines on page 117 Continuing the steps from Adding an Image to the Mosaic on page 115 1 Under Mosaicking Steps click Collect Cutline 2 Atan appropriate zoom level where you can see the detail in the image position the cursor where you want to begin collecting the cutline Under Cutline Information click Add For more information about how to see the details in the image more clearly see Changing the Layout in the Manual Mosaicking Window on page 118 OrthoEngine User s Guide 115 Chapter 9 Mosaicking Your Images 3 Click in the viewer to outline a polygon around the area that you want in the Mosaic Area Draw the cutline in the areas that appear in gray or cyan and include s
92. Set Camera Calibration icon 3 Inthe Focal Length box type the focal length in millimeters 4 Inthe Principal Point Offset boxes type the x and y offsets in millimeters 5 Under Chip Information for digital or video cameras only Inthe Width and Height boxes type the width and height of the camera s CCDs in millimeters Inthe Y Scale Factor box type the parameter from the manufacturer s specifications or from the camera calibration report if available 6 Under Radial Lens Distortion type the RO to R7 values or click No Distortion if the coefficients are not available If you have a table of distortion pairs click Compute From Table In the Distance Units list select a unit Enter a value in the Radial Distance box and the Radial Distortion box and then click Accept Repeat this step with each set of distortion pairs Once you have completed the table click Accept at the bottom of the window 7 Under Decentering Distortion type the coefficients or click No Distortion if the coefficients are not available 8 Under Fiducial Marks for standard aerial cameras only Click one of the Position options where the fiducial marks will be collected Inthe X and Y boxes type the x and y coordinates of the fiducial marks in millimeters If you do not have calibrated fiducial coordinates click Compute from Length and type your measurements in the Compute Fiducials window 9 Inthe Photo Scale box type
93. Using the Rational Functions Math Model Starting a Project Using the Rational Functions Math Model The Rational Functions Math Model is a simple math model that builds a correlation between the pixels and the ground locations For more information see Understanding the Rational Functions Math Model on page 6 To start the project 1 On the OrthoEngine window in the File menu click New 2 On the Project Information window in the Filename box type a file name for your project 3 In the Name box type a name that you want to appear on the title bar of the OrthoEngine window 4 Inthe Description box type a description of the project that will help you to identify its contents 5 Under Math Modelling Method click Rational Functions 6 Under Options select the source of the coefficients for the Rational Function Math Model Click Compute from GCPs when the Rational Functions coefficients are calculated based on the ground control points GCPs that you collect Click Extract from Image File when you want to import the coefficients from a file Some data providers compute the Rational Functions coefficients based on their knowledge of the sensor and distribute the coefficients and the image in an NITF file Also the IKONOS GEO Ortho Kit and QuickBird Basic with RPC Kit products contain a text file with the coefficients 7 Click Accept Y s Tip When you are using the IKONOS GEO Ortho Kit you can achiev
94. V i j is the original value at location i j If only the first Gaussian SQ value is specified then the Gaussian Filter is a low pass filter with a square frame of 2 SQ 1 As a result the image will be blurred If the second Gaussian SQ value is specified then the Gaussian Filter is a band pass filter with a frame of 2n 1 where n is the larger of the two SQ values The resulting image is the difference of the image produced with the second SQ subtracted from the image produced with the first SQ As a result it will detect sudden intensity changes in the image User Defined Filter The User Defined Filter resampling option determines the gray level from the weighted average of all the pixels in a square or rectangular frame surrounding the input coordinates and assigns the value to the output coordinates The weight applied to each pixel in the frame is defined in a Kernel File that you create with a text editor such as Notepad Click Browse to select the Kernel File 106 PCI Geomatics Understanding the Resampling Options For example if you wanted to create a 3 by 3 Kernel File you could define it as this 1 1 0 1 3 1 1 1 1 The Kernel File moves over the image Each pixel that falls within the frame is multiplied by the corresponding number in the filter and then summed to produce the output value Radar Gamma Filter The Radar Gamma Filter resampling option determines the gray level for eac
95. abase Channels click the DEM channel If you are editing an epipolar DEM both an image channel and a DEM channel may be available Click the image channel for channel 1 and then click the DEM channel for channel 2 Switching back and forth between the image and the DEM in the viewer can help you identify features in the DEM that need correction 5 Under Database Window Selection you can limit the DEM to a specific size Click Preview and drag the white guidelines to frame the area that you want Click Overview to reset the Database Window Selection window to the default 6 Click Load amp Close Ho step in your project For the next step in your project see Editing the Digital Elevation Model on page 75 74 PCI Geomatics Switching Between the Image Channel and the DEM Switching Between the Image Channel and the DEM If you are editing an epipolar DEM the file may contain both an image channel and a DEM channel which can be opened in the viewer see Opening the Digital Elevation Model Editing Windows on page 74 You can switch back and forth between the channels to identify features in the DEM that need correction Select Show Image to view the image Select Show DEM to view the DEM Editing the Digital Elevation Model Digital elevation models DEMs may contain pixels with failed or incorrect values You edit the DEM to smooth out the irregularities and create a more pleasing DEM For example a
96. affect the residual errors You may want to use a topographic map as a ground control source however features on topographic maps may be shifted several meters for aesthetic reasons This limits the accuracy of the coordinates that you can obtain from the map Also the detail visible on a 1 50 000 scale topographic map may not be compatible with the high resolution of an aerial photograph For example if you choose a road intersection in a topographic map as your coordinate the same road intersection in the aerial photograph may consist of several pixels Therefore the residual error will likely be larger than a pixel An existing LANDSAT orthorectified image may make a convenient ground control source for registering a new IKONOS image but the resolution of the LANDSAT image is 30 meters and the resolution of the IKONOS raw image is 1 meter Therefore even if you could pick the right pixel in the IKONOS image your GCP from the LANDSAT image is only accurate to 30 meters You cannot achieve accuracy of 2 to 4 meters unless your ground control source is equally accurate At first glance a residual error of 250 meters in ground distance may appear too high However if your raw data has a resolution of 1000 meters such as AVHRR you have already achieved sub pixel accuracy Identifying Errors in the Math Model Although residual errors are not necessarily mistakes that need to be corrected they may indicate problems with the math
97. age 83 2 Adjust the images in the 3 D viewer see Adjusting the Alignment in the Stereo Viewer on page 85 3 Create a layer see Creating a Layer on page 85 or import a layer see Loading a Layer on page 87 4 Draw vectors see Adding Points to a Layer on page 88 Adding Lines to a Layer on page 88 Adding Polygons to a Layer on page 89 5 Edit vectors if necessary see Using the Vector Editing Tools on page 90 6 Type attributes for the vectors see Designing the Attribute Table on page 92 7 Savethe layers see Saving a Layer on page 93 8 Click Close Selecting the Stereo Pair As described in Understanding 3 D Stereo Viewing and Editing on page 81 your eyes are the key to viewing in three dimensions 3 D quote Having the stereo images in the wrong order left image on the right and vice versa will not affect processing but it will cause some visually disturbing effects if you try to view the epipolar pair in three dimensions 3 D Our brains are trained to interpret the images seen from our left and right OrthoEngine User s Guide 83 Chapter 7 Editing Features in 3 D Stereo eyes in a certain way If the images are in the wrong order we cannot compensate for the error so for example we may see mountains that look like valleys instead If this occurs select the images in the opposite order To select a 3 D stereo pair 1 On the OrthoEngine window in t
98. al Positioning System GPS with or without Inertial Navigation System INS data the bundle adjustment can be computed immediately Due to the ephemeris data the bundle adjustment for Satellite Orbital projects is computed immediately with or without GCPs or tie points You can add GCPs and tie points to refine the math model s solution Not all the GCPs in your project will have the same reliability When the bundle adjustment is computed the GCPs tie points GPS data and INS data will be automatically weighted inversely to their estimated error The most accurate GCPs or tie points should affect the solution the most and the least reliable should affect the solution the least Using many GCPs and tie points provides redundancy in the observations so that a few bad points will not greatly affect your model and the bad points will be easier to identify Once the sensor orientation is calculated it is used to drive all the other processes such as digital elevation model extraction editing in three dimensional stereo and orthorectification You must obtain an accurate bundle adjustment solution before continuing with other processes Performing the Bundle Adjustment for Rigorous Math Models The bundle adjustment is the computation of the rigorous math model The image is not manipulated at this point For more information see Understanding the Bundle Adjustment for Rigorous Math Models on page 55 OrthoEngine User s Guide
99. alternately in black and white or in color Special stereo hardware such as specialized graphics cards and shutter glasses or polarizing monitors are used to filter the images so that each image is only displayed to the appropriate eye The OpenGL display method provides a more natural stereo viewing experience than the Anaglyph method but it requires more expensive hardware 7 Click Load Pair Note A To select a new stereo pair from the 3 D Viewing window click Select Stereopair to open the 3 D Stereo Pair Selection window and continue with step 3 of Selecting the Stereo Pair iex step in your project See Navigating Within the 3 D Viewing Window on page 84 Navigating Within the 3 D Viewing Window To begin working in the viewer you must switch from the mouse pointer to the stereo cursor The stereo cursor is made of two cursors one is only displayed to the left eye and the other is only displayed to the right eye Your brain receives this information and unites these cursors into one three dimensional 3 D cursor This allows you to perceive the depth and height of the objects in the viewer By adjusting the difference in x coordinate or parallax between the left and right cursors you control the apparent height ofthe cursor This way you can position the cursor not only in x and y but also in z The stereo cursor remains in the viewer When you move outside the viewer the stereo cursor is left behind in the
100. alue 7 Click Close Rejoining Stitching Image Tiles Some ASTER IKONOS QuickBird and SPOT images may be delivered to you as image tiles If the image tiles were cut from a strip of data acquired on the same day in a single pass of the satellite you can stitch the tiles into one image and rebuild the orbital data for the whole strip Therefore you can work with one large image instead of working with several smaller images which offers some advantages Less images to orthorectify and mosaic Fewer ground control points GCPs to collect since you have to compute fewer math models More coverage by the math model by bridging over obscured areas such as areas under cloud cover where you cannot collect GCPs 126 PCI Geomatics Setting the Automatic Backup However computing the math model on the image tiles may provide better fit to the ground control than a math model for a large scene You can stitch the following products ASTER level 1A data SPOT level 1A data IKONOS GEO product IKONOS GEO Ortho Kit product QuickBird Basic product To stitch images 1 Start a satellite project see Starting a Project Using the Satellite Orbital Math Mode on page 10 2 Save the image tiles on your disk see Reading Satellite Images from a CD or a Digital Distribution Format on page 15 3 Inthe main menu click Utilities 4 Click Stitch Image Tiles 5 In Satellite click the sensor ty
101. and adding vectors to the layer for each stereo pair you will end up with a vector layer for the entire project To create a layer 1 Under Vector Layer Information click New Layer 2 On the Create New Layer window in the Name box type a label for the new layer 3 In the Description box type a description of what the layer will contain 4 Under Georeferencing Info the projection is set by default You can change the projection however this may significantly affect the performance For information about changing the projection see Changing the Projection When Creating a New Layer on page 86 The bounds are set by default to the combined extents of the selected stereo pair If you do not want to change the bounds go to step 8 5 In the Bounds list click Geocoded to enter the bounds in georeferenced units or click Geographic to use Longitude Latitude units 6 Inthe Upper Left boxes type the coordinates of the upper left corner of the layer 7 Inthe Lower Right boxes type the coordinates of the lower right corner of the layer 8 Click Accept The new layer appears in the Vector Layer Information table fes step in your project See Adding Points to a Layer on page 88 Adding Lines to a Layer on page 88 and Adding Polygons to a Layer on page 89 Changing the Projection When Creating a New Layer The projection of the new layer is set to the project s output projection by default We recomm
102. arate window Mosaic Image Reference to display the images already mosaicked in red the image that you are adding to the mosaic in green and a reference image in blue The reference image can be any image that overlaps the image that you want to add to the mosaic Seeing where and how the two images overlap can help you decide where to place the cutline Regenerating the Mosaic After the mosaic is complete you may discover some areas that you want to change You can use Manual Mosaicking to edit the cutlines or adjust the color balancing for the images as required and then use Reapply Mosaicking to reassemble the mosaic file You can use Reapply Mosaicking to Preview the mosaic Reproduce missing mosaic files Regenerate the mosaic at different resolutions Create a subset of the mosaic by changing the size of the Mosaic Area and then regenerating the mosaic To regenerate the mosaic 1 On the OrthoEngine window in the Processing Step list select Mosaic 2 Click B the Reapply mosaicking icon He 3 On the Reapply mosaicking window click in the Use column to select or clear the images Only images with check marks in the Use column will be mosaicked Use the arrow buttons to scroll through the list of Images 4 Under Processing Options select Current Resolution to create the mosaic using the resolution set in the Set Projection window Different Resolution to set a new resolution for the mosa
103. are RE Layer PER C RR 87 Changing the Priority OFa Layer RP Rp eU DE DEED tere e E Ee E E EDU 87 Changing the Visibility Of a Layer ieseni iine dejais 87 Changing the Color of the Vectors in a Layer errar 87 Changing the Type of the Layer ivonne aa de vag 88 Adding Points tora ayer initia dine nis edendi eene 88 Adding Lines toa Layer A een ed e da t i EE Rene 88 Adding Polygons to a ei RN 89 BEIDE DECR O 90 Using SAP TO Lire eO tne tre sce ER EE RE GEB OI DU teu io e e ET 90 Using the Vector Editing TOOls temo A 3ID ecd uie d cu et etes eed seed ecu eer aaa 90 Insertingi Vertex cere ere RR ERE rr enn MERERI RE SUD ERE RN 91 Deleting a VET AX cet E 91 Deleting a Lirie or Polygon eret ree A A aee A td 92 MoViNg a Vertex or a Poltica 92 Iseversing an Action UN ie 92 Designing the Attribute Table O aii 92 Assigning Attribute Valles 12 iei aa 93 SAVING a LAY Ol sis 93 Deletirig a bayern reas tes 94 Using Shortcuts in the APR E 94 Extracting Vector Points from a Digital Elevation Model sessseeeeene enn enne n enne nnns et enrnen nne entre en nennen nene erre nnns 95 Extracting Contour Lines from a Digital Elevation Model sse nennen enne n
104. ate a Digital Elevation Model on page 64 Using Ground Control Points Tie Points and or Elevation Match Points to 63 Chapter 6 Generating Digital Elevation Models Generate a Digital Elevation Model on page 64 Using Vectors to Generate a Digital Elevation Model on page 65 Extracting Digital Elevation Models from Epipolar Pairs on page 71 Using Rasters to Generate a Digital Elevation Model Data providers and government agencies offer digital elevation models DEMs as rasters Many raster DEMs are available without charge and can be downloaded from the Web For example the USGS distributes 1ts DEM products which are based on USGS Digital Orthophoto Quads and Quarter Quads DOQs DOQQs from their Web site Since you may not find one raster DEM that meets your requirements you can merge several existing DEM raster files to generate a single seamless DEM to cover your project area Also if you generated your own DEMs and chose to edit them before they were geocoded see Extracting Digital Elevation Models from Epipolar Pairs on page 71 you can integrate the resulting geocoded DEMs with this procedure To import raster files to generate a DEM 1 On the OrthoEngine window in the Processing Step list select Import amp Build DEM 2 Click e y the DEM from raster file icon 3 On the Input DEM File Selection window type the path of a raster file or click Select to select a file To select mor
105. ation see Importing Images or Photographs into Your Project on page 15 5 Click Load amp Close On the Default Parameter Settings window enter the sensor information for the image If you are going to create many chips from the same image you can set the information as a default see Setting the Source Image Default Parameters on page 140 6 In the Sensor box type the name of the sensor or select the sensor from the list 7 In the Viewing Angle box type the angle in degrees between the axis of the sensor and the ground 8 In the Acquisition Date box type the day month and year that the image was taken 9 Inthe Resolution boxes type the x pixel size and the y pixel size in the units used in the image 10 In the General Description box type a description that will help you identify the chip 11 In the Scene Description box type the Scene ID 12 Click Accept Ros step in your project See Collecting the Chip on page 137 136 PCI Geomatics Working in the Chip Manager Viewers Working in the Chip Manager Viewers The Chip Manager contains two viewers The viewer on the PCI ImageChipsManager window displays the current chip in the database The other viewer displays the source image For more information about the features in the viewers see Understanding the Enhancements on page 121 and Using Zoom ReLoad and Pan on page 122 Changing the channel display fo
106. ays are available for you to increase or decrease the magnification of the image The zoom features available change depending on the viewer Click Zoom to Overview to decrease the magnification so the whole image appears in the viewer Click Zoom In or press PAGE UP to increase the magnification by increments Click Zoom Out or press PAGE DOWN to decrease the magnification by increments oe Click Zoom Interactive and drag a rectangle over the area you are interested in magnifying el Click Zoom 1 1 Image Resolution to adjust the magnification so that one screen pixel displays one image pixel pa Press PAGE UP to increase the magnification by increments or press PAGE DOWN to decrease the magnification by increments Press CTRL left mouse button to zoom in and CTRL right mouse button to zoom out Reload E Click Reload to update the image in the viewer and center it around the cursor Pan w Click Pan to move the image around with the cursor so that you can view all the areas on it Loading Vectors Over an Image To import vectors 1 Click the Open new or existing photo icon For information how to open an image see Opening Images on page 17 2 Open an orthorectified or geometrically corrected image 3 Click the amp Load Vector icon 4 On the General Vector Information window click Load and choose a file containing vectors for the area covered by the image 5 Select the appropriate s
107. blue image and the blue lens filters out the red image so each eye is presented with a different image from the stereo pair The advantages of using this technology The technology is available on all platforms No special hardware is needed other than the inexpensive 3 D glasses You can use single or double monitor configurations You can set your monitor to full resolution The disadvantages of using this technology The images must be in grayscale The range of colors for viewing the vectors and the cursor is limited You may experience eye strain or fatigue To reduce eyestrain and fatigue take frequent breaks arrange your lighting to minimize glare and reflections on your screen and use the correct settings for your monitor Incorrect settings on your monitor can cause a noticeable screen flicker particularly on larger screens Also you can alleviate eye strain by readjusting the parallax between your images see Adjusting the Alignment in the Stereo Viewer on page 85 Viewing in 3 D Using OpenGL Technology OpenGL technology uses special stereo hardware such as specialized graphics cards and shutter glasses or polarizing monitors and glasses to filter the images so that each image is displayed to the appropriate eye Shutter glasses use high speed liquid crystal shutters to block the view from one eye or the other in sync with the monitor displaying alternating images from the stereo pair Polarizing m
108. certain way If the images are in the wrong order we cannot compensate for the error so for example we may see mountains that look like valleys instead You can limit the amount of memory used for generating the epipolar pairs to allow other tasks to be completed In Working Cache type the amount of RAM that you want to allocate to create the epipolar pairs In Down Sample Factor type the number of image pixels and lines that will be used to calculate one epipolar image pixel For example typing 2 means that two adjoining pixels and two adjoining lines will form one pixel in the epipolar image In Down Sample Filter click the method used to determine the value of the epipolar image pixel when the Down Sample Factor is greater than 1 Click one of the following Average to assign the average image pixel value to the epipolar image pixel The average is obtained by adding the image pixel 70 PCI Geomatics Extracting Digital Elevation Models from Epipolar Pairs values that will become one epipolar image pixel and dividing that value by the number of image pixels used in the sum Median to assign the median value of the image pixels to the epipolar image pixel The median is obtained by ranking the image pixels that will become one epipolar image pixel according to brightness The median is the middle value of those image pixels which is then assigned to the epipolar image pixel Mode to assign the mode value
109. covers the area defined by the Mosaic Area Elevation Source Area to generate a DEM that covers the area where elevation data exists recommended Photo Extents to generate a DEM that covers the extents of all the photos in the project This is useful when you want the DEM to cover the images being orthorectified but extrapolating beyond the elevation source area can cause significant errors in your project In the Background Elevation box type the value to represent the background or No Data pixels in the DEM Three parameters determine the final output of the DEM the size the resolution and the bounds of the DEM You can specify two out of the three and OrthoEngine with calculate the third To set the size and bounds for the DEM click Use pixels lines and bounds in the list To set the size and resolution for the DEM click Use pixels lines and resolution in the list To set the bounds and resolution for the DEM click Use bounds and resolution in the list Depending on which option you selected in step 4 set the two parameters of your choice To set the Size Type the number of pixels in the Pixel box and type the number of lines in the Lines box to determine the size of the DEM To set the Resolution Type the x and y dimensions of the pixel size in the corresponding X and Y boxes To set the Bounds In the Bounds list click Geocoded to enter the bounds in georeferenced units or click Geographic to use L
110. ct To automatically collect fiducial marks 1 Import all the images for your project For more information see Importing Images or Photographs into Your Project on page 15 2 Manually collect the fiducial marks for one image For information see Collecting Fiducial Marks Manually on page 25 3 When you are satisfied with the results for that image under Errors click Auto Fiducial Collection 4 Inthe Question window asking Do you want to overwrite photos with fiducial marks click Yesto use the pattern matching on all fiducial marks on all Images No to use the pattern matching only on the images without measured fiducial marks 5 After the Progress Monitor closes click Accept You can verify the accuracy of the fiducial mark collection under Errors in the Fiducial Mark Collection window or you can view the fiducial rpt report in the folder where the project is saved rw step in your project See Understanding Ground Control Points on page 33 Understanding Exterior Orientation Exterior orientation represents a transformation from the ground coordinate system to the photo coordinate system In most projects exterior orientation is computed from ground control points GCPs and tie points Adding estimated or observed exterior orientation to your project reduces the amount of GCPs that you need it helps to automate the tie point collection and it decreases the time needed to set up the pro
111. ct 18 masks 75 Match Channel 44 Match Chips 44 matching features on chips 45 Matching Threshold 54 Math model Aerial Photography 5 9 change threshold values 132 export 129 None Mosaic Only 12 number of iterations 132 performing bundle adjustment 55 Polynomial 7 11 Rational Functions 6 11 Residual Report 58 Satellite Orbital 5 10 Thin Plate Spline 8 12 troubleshooting the solution 56 understanding bundle adjustment 55 understanding the solution for Polynomial math model 56 understanding the solution for Rational Functions math model 56 OrthoEngine User s Guide 151 understanding the solution for rigorous models 55 understanding the solution for simple models 56 understanding the solution for Thin Plate Spline math model 56 using right model for IKONOS 6 Math Modelling Method See Math model Mean Sea Level MSL 126 Median Filter 106 Median filter 71 78 merge chip databases 139 merge DEM raster files 64 Merge image chips Chip Manager 139 Merged database Chip Manager 139 MERIS intro to OrthoEngine 1 Min Difference 114 Min Relative Difference 114 minimum number of GCPs 34 Mix Color Chip Manager 141 mix your own color for cursor Chip Manager 141 Mode filter 71 Model Calculations 56 modify a tablet 48 Mosaic Area 112 add image 116 editing Mosaic Extents 113 select existing 112 Mosaic Extents 113 mosaic file See Mosaic Area Mosaic Image Reference 118 Mosaic Overlay 118 Mosaicking add image 115
112. ctify the image However this will not produce results as accurate as using a DEM Type the average elevation in the Elevation Offset box Understanding Geometric Correction Simple math models such as Polynomial Thin Plate Spline and Rational Functions use ground control points GCPs to calculate a transformation that will warp the raw image to fit the ground coordinates The warping the raw image is known as geometric correction shown in Figure 8 2 For more information about simple math models see Understanding the Math Models on page 5 and Understanding the Solution for Simple Math Models on page 56 The quality of the geometrically corrected image is directly related to the quality and number of the GCPs and the math model that you choose Selecting the wrong math model collecting too few GCPs or inaccurately collecting the GCPs may result in a geometrically corrected image that does not suit your needs 100 PCI Geomatics Geometrically Correcting Your Images Figure 8 2 The process of geometric correction warp the raw image to fit the ground coordinates raw image geometrically corrected image Geometrically Correcting Your Images Before you process your images you must make sure that the Output Pixel Spacing on the Set Projection window is set correctly For more information see Setting the Projection on page 13 The Output Pixel Spacing determines the size of the correct
113. cting and correcting errors in GCP coordinates To verify the derived transformation you should acquire a number of Check Points large enough to ensure a thorough verification such as an amount equal to half the number of GCPs For more information about Check Points see Troubleshooting the Math Model Solution on page 56 The Thin Plate Spline Math Model can handle more variation in terrain than the Polynomial Math Model because it recognizes three dimensional GCPs and minimizes the extrapolation errors that can occur between the GCPs To compute a warping transformation accurately you should collect GCPs at the extremes ofthe terrain and along the breaklines If you use the Thin Plate Spline Math Model with an image in rough terrain it may be necessary to acquire hundreds of GCPs For this reason the Thin Plate Spline Math Model is recommended only for distortions that can be accurately represented using up to a few dozen GCPs It is not recommended for the removal of terrain distortions or for images of rough terrain A rigorous model such as the Satellite Orbital or Aerial Photography Math Model may be the better choice in these cases PCI Geomatics Starting OrthoEngine Starting OrthoEngine To start OrthoEngine choose one of the following 1 From Windows click the Start button click Programs click PCI Geomatics and then click OrthoEngine 2 If Geomatica is running click is the OrthoEngine icon on th
114. d Image on page 37 Collecting Ground Control Points from Vectors on page 39 Collecting Ground Control Points from a Chip Database Manually on page 40 Collecting Ground Control Points from a Chip Database Automatically on page 43 or Collecting Ground Control Points from a Tablet on page 47 Figure 5 1 The relationship between the ground coordinate system and the image coordinate system e wy image coordinates ae a 1024 N p coordinates x 450 000 y 3 500 000 z 180 ground 33 Chapter 5 Collecting Control Points and Computing the Math Models Choosing Good Ground Control Points The quality of your ground control points GCPs directly affects the accuracy of your math model and that in turn determines the outcome of your project When you collect the GCPs Choose features that you can identify accurately at the resolution of the raw image Select features that are close to the ground Features that rise above the ground such as buildings may appear to lean in the image Therefore a point collected from the top of the feature may be displaced from the actual ground coordinate Avoid using shadows as GCPs Although shadows may be easy to see in the image they are not permanent and can move from one image to another Beware of selecting common or repetitive features as GCPs such as parking lots or lines on a highway When you try to identify the featur
115. d a Global Positioning System GPS to obtain the x y and z coordinates for each image center and you estimated the omega phi and kappa rotations or they were supplied by an Inertial Navigation System INS OrthoEngine User s Guide 43 Chapter 5 Collecting Control Points and Computing the Math Models To automatically collect ground control points from a chip database 1 On the OrthoEngine window in the Processing Step list select GCP Collection 2 On the OrthoEngine window click mM the Automatically collect GCPs from chip database icon 3 Inthe Automatic GCP Collection window under Chip Database type the path for the chip database or click Browse to select chip database file Search result displays the number of chips in the database You can click Search Criteria to limit the number of chips used in the correlation process For Information about searching the chip database see Searching for Chips in a Database on page 42 4 Under Photos in the Use column click to select or clear the check marks to select the images that you want to use in the matching process Only images with check marks in the Use column will be used Click Use all to select all the images under Photos or click None to clear all of them You can only select images with Available listed in the Status column and Yes in the Model column which means that the image has a computed math model 5 In Match Channel click the number of
116. derstanding Exterior Orlentatlon 2 2 02 recie ri o deg eate qud cere test eee zc mee debe Bee tate eese ng doeet 26 Importing GPS INS or Exterior Orientation Data from a Text File sesssssseseeeeene nene nnne enn ener n nene enne nene nnne 28 Entering the Exterior Orientation Manually sss ennemi nen 29 ii Changing Photo Orientation coi ii 30 Defining a Clp REg OT 00 A A A A A A tt ug 30 Chapter 5 COLLECTING CONTROL POINTS AND COMPUTING THE MATH MODELS Understanding Ground Control Points renaming e a Ebo 33 Choosing Good Ground Control PoltS tai a dan 34 Collecting the Right Number of Ground Control Points ooooooccnnncccninncononacanananccnnoncnr non ccoo nn cnn rra rre rr 34 Determining the Right Combination of Ground Control Points and Tie Points for the Satellite Math Model 35 Using Auto Locate e cC iaaa 35 Using Bundle Update 55 1 pnta A A Aa iii 36 Collecting Ground Control Points Manually oonnncnnnnnnnnnnnnnnnnnccnnoncnnnn oran 36 Collecting Ground Control Points from a Geocoded Image sss eene ennemi enne nennen nere enne e erret nennen nnn 37 Collecting Ground Control Points from Vectors esssssseeeeee eene nne nrnen nenne ennr eter nen ener n nene enne in nensi nnne erret nennen enn 39 Collecting Ground Control Points from a Chip Database Manually essen e
117. determines the number of pixels on either side of the cutline that are used to blend the seam However in areas containing bright or significantly different features setting the Blend Width too high may cause ghosting or doubling of the features Understanding Cutlines When you create a mosaic you want to crop the images so the best portions of the images are seamlessly joined together A cutline is a polygon that outlines the portion of an image that will be used in the mosaic As the cropped images are added to the Mosaic Area the data in overlapping areas is covered by the most recent addition Areas where several images overlap provide you with the more opportunities to find the best location for the cutlines When you save the project the cutlines are saved with their corresponding images To make the seams between images less visible select features that are consistent in tone and texture low to the ground uniform in appearance and conspicuous such as roadways and river edges Features that display clear boundaries provide a natural camouflage for the seam Avoid Buildings or man made features since they may lean in different directions in the imagery Large bodies of water because waves may look different in different images and water tends to have different color in different images Areas that are significantly different in color and texture such as forests and cultivated land since they may look dif
118. digital distribution format read satellite images from 15 digital elevation model See DEM Digital Video Camera 9 digitizing table 45 47 Dimap format 20 Display Chips 42 43 display image 17 display images 129 Display overall image layout 55 Display overall layout 54 Distortions correct 55 56 non symmetric see Decentering Distortion pin paper map to tablet 45 radial see Principal Point Offset symmetric see Radial Lens Distortion distribute tie points 54 distribution format 16 DMS 28 DOQQs 64 DOQs 64 Double Window 118 downsampling 70 Drag out rectangle on image Chip Manager 138 Drag out square on image Chip Manager 138 E Earth Model 13 Earth Radius 23 24 Edge features 114 Edit Point 59 Editing the DEM 71 75 76 77 78 OrthoEngine User s Guide 147 elements of exterior orientation 55 elevation match point to generate DEM 64 Elevation Match Point Collection 65 Elevation Offset 100 Elevation Scale 100 ellipsoid 12 14 126 Enhancements Adaptive 121 Equal 121 Equalization 121 Exclude Min Max 121 Hold 121 Infrequency 121 Linear 121 recalculate 121 Root 121 Set Trim 121 Tail Trim 121 understanding 121 Enter GPS INS or exterior orientation data manually 29 Entire Image mosaicking 114 EOC intro to OrthoEngine 1 minimum number of GCPs 34 EOSAT IRS 18 EOSAT LANDSAT 5 18 epipolar images 69 for 3 D stereo 82 Equal 121 Equalization 121 equation Decentering Distortion 22 Earth Radius 23 Ele
119. displays the GCPs from the image in the Working viewer only Click the Reference button to switch the viewer to Working You can collect the same GCP in each image by clicking Reference in a viewer collecting the GCP and then repeating the process for each image 2 s Tip If you are working in a project with a large volume of images we recommend that you enter the fiducial marks and ground control points for a limited number of images up to five complete the bundle adjustment for the math model and then check for errors before continuing It is easier to locate bad points on a few images than over the entire project To collect ground control points from a tablet 1 Setup the digitizing table For more information see Setting Up the Tablet on page 46 2 Onthe GCP Collection window the Point ID is generated automatically You can type a new label in the Point ID box however all points ground control points check points tie points and elevation match points in the image must have unique labels 3 Inthe list below the Point ID box click Ground Control Point GCP to use the GCP to calculate the math model Check Point CP to check the accuracy of the math model For more information see Troubleshooting the Math Model Solution on page 56 4 Youcanselect Auto Locate and or Bundle Update to aid with collection For more information see Using Auto Locate on page 35 and Using Bundle Update on page 3
120. e Geomatica Toolbar 3 For Unix after you have set up the path for Geomatica type in the prompt orthoeng exe Ho step in your project Depending on the math model that you are using select one Starting a Project Using the Aerial Photography Math Model on page 9 Starting a Project Using the Satellite Orbital Math Model on page 10 Starting a Project Using the Rational Functions Math Model on page 11 Starting a Project Using the Polynomial Math Model on page 11 Starting a Project Using the Thin Plate Spline Math Model on page 12 Starting a Project to Mosaic Existing Georeferenced Images on page 12 Starting a Project Using the Aerial Photography Math Model The Aerial Photography Math Model is a rigorous model that compensates for known distortions to calculate the position and orientation of the camera at the time when the image was taken For more information see Understanding the Aerial Photography Math Model on page 5 y You should not use the Aerial Photography Math Model when you are using only a portion of the original image when the image has been processed or when you do not have or cannot estimate the camera calibration information To start the project 1 On the OrthoEngine window in the File menu click New 2 On the Project Information window in the Filename box type a file name for your project This will be the name used when you save your project
121. e A hot spot is a common distortion that results from solar reflections Hot Spot normalizes the brightness over the image but it does not remove spot reflections from lakes cars and buildings Across Image 1st Order to correct the gradual change in brightness from one side of the image to the other OrthoEngine computes a linear equation for the column averages of the image to compensate for the consistent across track gradation in tone Recommended for ScanSAR and other imagery Across Image 2nd Order to correct the gradual change from dark to bright to dark or vice versa across the image also known as an antenna pattern OrthoEngine computes a quadratic equation for the column averages of the image to compensate for the varying across track gradation in tone Recommended for ScanSAR and other imagery Across Image 3rd Order to correct gradual bright and dark patterns from one side of the image to the other OrthoEngine computes a cubic equation for the column averages of the image to compensate for the inconsistent gradation in tone Recommended for ScanSAR and other imagery You can select Regenerate offline orthos to regenerate orthorectified images with a Stale or Offline status Projects with None Mosaic Only as the math model do not have this option OrthoEngine can orthorectify the images and mosaic them in one step see the tip on page 99 Automatic color balancing applies tonal and contrast adjustments over the
122. e Use the GPS INS data alone as User Input and accept them as correct or use ground control points and or tie points to refine the GPS and INS results For more information see Starting a Project Using the Aerial Photography Math Model on page 9 If you have an existing triangulation solution for the project you can import it as a known solution for the exterior orientation It allows you to skip GCP and tie point collection GPS INS and triangulation data is usually already calibrated to the orientation of the images but may require kappa rotations in some cases It is quite common for some formats such as Albany and Pat B to have kappa values rotated due to different flight lines You should rotate the kappa value according to the scanning direction Kappa is the counter clockwise angle required to rotate from map north to photo north up For example a scanned photo with north up should have kappa near 0 degrees while a photo with north right should have kappa near 90 degrees If a photo is scanned with north up and the input kappa value is about 90 degrees you will need to rotate the kappa value by 90 degrees 90 degrees is equivalent to 100 gradients For Reference Elements of Photogrammetry Third Edition by Paul R Wolf Digital Photogrammetry An Addendum to the Manual of Photogrammetry published by American Society for Photogrammetry amp Remote Sensing Figure 4 2 Understanding Omega Phi and Kappa positive of t
123. e in the image it may be difficult to select the right one Identify the features in the raw image that you want as ground control before collecting GCP coordinates in the field using a GPS or ground survey Collect GCPs from a variety of elevations in a wide distribution over the image and the project Collect GCPs in an area of overlap between two or more images when possible The same ground coordinate collected in multiple images helps to produce a more accurate model Collecting the Right Number of Ground Control Points The following is the minimum number of ground control points GCPs to collect but we recommend that you collect more than the minimum to ensure accuracy However collecting over 20 GCPs per image does not significantly improve the accuracy for most math models To improve the accuracy collect GCPs evenly throughout the image at a variety of elevations and in areas where images overlap Also the quality of the GCPs impacts the number needed to ensure accuracy Table 1 Minimum Number of GCPs Minimum Math Model GCPs Recommended Aerial Photography 3 or 4 per 3 per photo for highest project accuracy Satellite Orbital Optical SPOT 1 TO 4 4 per image depends on GCP quality SPOT 5 6 per image depends on GCP quality IRS ASTER EOC 6 per image 6 to 8 per image LANDSAT QUICKBIRD 6 per image 10 to 12 per image IKONOS 8 per image 10 to 12 per image SAR images RADARSAT ERS JERS
124. e name of your choice Under Rotate Flip Operation click a rotate button and or a flip button to achieve the direction of your choice In Working Cache type the amount of RAM that you allocate for this process You can adjust the Working Cache to limit the amount of memory used to allow other tasks to be completed Due to disk cache requirements rotations of 90 and 90 degrees take much longer than 180 degree rotations Under Processing Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours Click Start Rotation When the photograph is rotated and or flipped the photograph s GCPs tie points clip area fiducial marks and calibration edge are modified to match the new orientation Defining a Clip Region The Clip Region identifies an area of interest from an uncorrected satellite or aerial images for use as an input window OrthoEngine will only process the area inside the clip region which results in smaller 30 PCI Geomatics Defining a Clip Region files and faster processing You can also use it to remove the data strip and fiducial marks from photographs To define a clip region lA On the OrthoEngine window in the Processing Step list select Data Input If the Open Photo window is not open click put the Open new or existing photo icon In the Open Photo window select an image Click Open Click Zoom to Overview
125. e 136 open an image 17 Open new or existing photo 15 17 Open Photo 17 OpenGL technology 82 Opening the PCI Chip Manager 135 orbit information See Read satellite images ORBIT ORIENTED product 18 orientation of the camera 27 orientation of the sensor 55 Orthorectification default output format 128 Elevation Offset 100 Elevation Scale 100 processing the images 98 resampling options 104 Sampling Interval 102 set channel type 129 Status Descriptions 103 troubleshooting 104 understanding 97 outliers 57 Output DEM 67 Output Line Spacing 14 output of DEM 67 Output Pixel Spacing 14 Output Projection 13 Overall Layout 54 overlap 52 54 64 70 73 Overlay 118 Overview 55 Overview Chip Manager 137 Overviews 129 P Pack Chip Manager 140 Pan 122 Parity 46 49 61 PARITY parity 61 Pat B 27 PAUSE n 60 PCIDSK 128 Perform Bundle Adjustment 59 Perform Merge Chip Manager 139 performing bundle adjustment 55 phi 27 55 photo north 27 Photo Orientation 30 Photo Scale 23 24 Pixel Sampling 74 Pixel Spacing 14 80 place cursor 123 plot the distribution of GCPs 54 Point Mode 49 61 point read 49 POINT point mode 61 points 65 88 polarizing monitors and glasses advantages and disadvantages 82 Polygon mask 76 Polygons 66 89 PolyLine 75 Polynomial Math Model 7 minimum number of GCPs 35 OrthoEngine User s Guide 153 Starting a project 11 understanding solution 56 Polynomial Order
126. e Bundle Adjustment for Rigorous Math Models on page 55 and Troubleshooting the Math Model Solution on page 56 Collecting Ground Control Points Manually If you have several raw images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The GCP Collection window collects and displays the GCPs from the image in the Working viewer only Click the Reference button to switch the viewer to Working You can collect the same GCP in each image by clicking Reference in a viewer collecting the GCP and then repeating the process for each image 2 s Tip If you are working in a project with a large volume of images we recommend that you enter the fiducial marks and ground control points for a limited number of images up to five complete the bundle adjustment for the math model and then check for errors before continuing It is easier to locate bad points on a few images than over the entire project To collect ground control points manually 1 On the OrthoEngine window in the Processing Step list select GCP Collection al 2 Click al the Open new or existing photo icon to open an image For information how to open an image see Opening Images on page 17 On the OrthoEngine window click ER the Collect GCPs Manually icon On the GCP Collection window the Point ID is generated automatically You can type a new label in the Point ID box however all p
127. e DEM is found or click Browse to select the file In the DEM Channel list click the DEM channel or click Select In the Background Value box type the background pixel value if necessary OrthoEngine may automatically extract the background pixel value from the DEM use the default values for the project or consider all the elevation values in the DEM as valid It is very important to specify the correct background pixel value or the contour lines will be generated using all the values in the DEM which may include large negative values normally used as the background values In the Contour Interval box type the span in DEM elevation units that you want between the contour lines In the Field Name list click a label for the attribute field where the elevation values of the contour lines will be saved If you choose the Z Coordinate label the attribute field is omitted since all vector contour lines are automatically assigned a z coordinate corresponding to their elevation values Under Input Window click Full Image to extract contours from the entire DEM Window to extract contours from a specific area In the Offset boxes type the pixel and line coordinates of the upper left corner of the area and in the Size boxes type the number of pixels and lines to specify its size Under Output Contour in the File box type the path where the contours will be saved or click Browse to select a path Click Generate Contours
128. e a Digital Elevation Model on page 64 Editing the DEM after it is geocoded When you use the Automatic DEM Extraction window to complete the entire process in one operation OrthoEngine builds a model based on all the selected epipolar pairs and uses that model when the DEMs are geocoded The geocoded DEMs are automatically stitched together and saved in a file Because OrthoEngine uses a model to process all the epipolar pairs the resulting integrated geocoded DEM is slightly more accurate than if you completed the process manually You can edit the geocoded DEM using 2D DEM Editing see Editing the Digital Elevation Model on page 75 however the file will not include the raw image To extract a digital elevation model l 2 Prepare the epipolar pairs See Creating Epipolar Images on page 69 On the OrthoEngine window in the Processing Step list select DEM From Stereo Click P the Extract DEM automatically icon On the Automatic DEM Extraction window under Stereo Pair Selection click in the Select column to select epipolar pairs or click Select All to select all the epipolar pairs that appear in the list If the epipolar pairs do not exist or are not available OrthoEngine will automatically generate the epipolar pairs using the options that you saved in the Generate Epipolar Images window In the Minimum Elevation and Maximum Elevation boxes type the estimated elevation for the terrain in the stereo pair
129. e first image that you add to your project The Set Projection window may open automatically after completing the Project Information window If it is open skip to step 3 To set the projection 1 On the OrthoEngine window in the Processing Step list select Project the Set Output and Default Projection icon 3 On the Set Projection window under Output Projection type the projection string for example UTM 17 T D000 in the text box beside the Earth Model button If you do not know the projection string Selecta projection type from the list to the left of the Earth Model button For UTM State Plane Coordinate Systems SPCS or Other projection types additional windows may open automatically for you to select the parameters to define the projection or click OrthoEngine User s Guide 13 Chapter 2 Starting your Project and Selecting a Math Model More to open these windows Select the parameters and click Accept Click Earth Model Click either the Datum or Ellipsoid tab Click a datum or an ellipsoid Click Accept If the output projection is State Plane Coordinate in feet or FOOT projection SPAF SPIF and FOOT all calculations are in feet DEMs can be in either feet or meters as long as the GCP Elevation Units are set for GCP collection and the elevation units are set on the Ortho Image Production window If the output projection is changed and there are some existing GCPs that cannot be pr
130. e following 1 From Windows click the Start button click Programs click PCI Geomatica V9 0 and then click Chip Manager 2 If Geomatica is running click the ChipMan icon on the Geomatica Toolbar 3 For Unix after you have set up the path for Geomatica type in the prompt chipman exe Creating a New Database To create a new database 1 Inthe main menu click File 2 Click New 135 Chapter 11 Creating a Chip Database 3 In the Chip Database name box type the filename for your new database 4 Click OK Ro step in your project See Selecting the Source for the Chips on page 136 Opening an Existing Chip Database You can open an existing chip database and add new chips To open a chip database 1 In the main menu click File 2 Click Open 3 Select your file Ros step in your project See Selecting the Source for the Chips on page 136 Selecting the Source for the Chips The source image is a geocoded image that you use to create the chips You can create several chips from one image If the image contains an orbit segment OrthoEngine can extract information required to complete the Default Parameter Settings window Otherwise type the information required manually To open the image 1 In the main menu click File 2 Click Source Image 3 Select the image 4 On the File window under Database Channels click the channel that you want For more inform
131. e lower right corner in the Lo Right row and the lower left corner in the Lo Left row You can also collect a point within the reference frame in the Other row 20 You can click Use Grid Pinning to define the size of the frame that you want to use to anchor the reference frame around each point that you want to use as a GCP For more information about Grid Pinning see Using a Tablet to Collect Ground Control Points on page 45 After clicking Use Grid Pinning the Grid Box Definition Panel opens automatically Click Geocoded from the list to use georeferenced units to anchor the reference frame or click Geographic to use Longitude Latitude units Determine the size of the frame that you want move the crosshairs of the puck to each corner of your frame and press the button to select each point as required in the Grid Box Definition Panel When the four points are set click Accept 21 In the Tablet Setup and Map Tie down window click Tie down Completed fos step in your project See Collecting Ground Control Points from a Tablet on page 47 Collecting Ground Control Points from a Tablet After you set up the digitizing table you can choose any feature that you can see clearly on the paper map and in the raw image as a ground control point GCP If you have several images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The GCP Collection window collects and
132. e operation to begin within the next 24 hours In the box under Directory for Temporary Files type the path for the temporary working files or click Browse to select a location The temporary files are deleted when the mosaic is complete 10 Click Generate Mosaic 114 PCI Geomatics Mosaicking Images Manually Y s Tip To view the mosaic click File from the main menu and select Image View Mosaicking Images Manually You can create your mosaic one image at a time or you can use Automatic Mosaicking to do the bulk of the work see Mosaicking Images Automatically on page 113 You can use Manual Mosaicking to edit the cutlines in an automatically mosaicked project or to replace unsatisfactory areas in the mosaic For each image that you want to include in the mosaic file you must complete four steps in sequence Follow the procedures in 1 Adding an Image to the Mosaic 2 Collecting the Cutline 3 Adjusting the Color Balance 4 Adding the Image to the Mosaic Area 2 s Tip Overviews quicken the display of your images but they add processing time when they are created To speed up mosaicking disable Build Overview See Understanding When To Build Overviews on page 129 Adding an Image to the Mosaic To mosaic your images 1 On the OrthoEngine window in the Processing Step list select Mosaic TN nae 2 Click 5 the Manual mosaicking icon pad 3 On the Manual Mosaicking window click
133. e path where the vector 3 grid will be saved or click Browse to select the file Click Create new segment to add a new segment to the output file or click Use existing segment to replace an existing vector segment 4 In the Segment list click the vector segment to be replaced or click 5 Select In the Grid Spacing box type the number of pixels in the input DEM that determines the space between two vector points Click Extract Extracting Contour Lines from a Digital Elevation Model 6 You can extract vector contour lines from a digital elevation model DEM raster and then save the contour lines to a vector layer You can 7 export the contour lines to any supported vector format or display them in three dimensions over an image and use them for quality control or editing Choosing between using contour lines or vector points is a matter of personal preference Vector points are easier to edit than contour lines 8 since you have fewer points to analyse Contour lines offer a more intuitive view of the terrain but you have more points to edit For more information about vector points see Extracting Vector Points from a Digital Elevation Model on page 95 To extract contours from a DEM l 2 On the OrthoEngine window in the Processing Step list select 3 D 9 Operations Click EA the Generate Contours icon ES 10 On the Generate Contours window under Input DEM in the File box type the path where th
134. e than one file On the Input DEM File Selection window in the File s box type the path with a wildcard character in the filename and press ENTER For example CAGeomatica demo V pix Under DEM Merge Set Candidates click the files of your choice and click the arrow 4 Click Move Up and Move Down as required to organize the files under Set of DEMs to Merge When a raster from the bottom of the list overlaps a raster from the top ofthe list the bottom raster will overwrite the top raster where the two overlap 5 Inthe Channel list click the channel that you want to use or click Select 6 In the Background Value box type the value representing the No Data pixels in the DEM 7 In the Resampling list click the processing method of your choice For more information see Understanding the Resampling Options on page 104 8 In Interpolate Holes you can click Yes to automatically interpolate data between the raster DEMs This is recommended for small gaps but not for large areas 9 Click Accept Ho step in your project See Generating the Digital Elevation Model from Rasters Vectors or Control Points on page 67 Using Ground Control Points Tie Points and or Elevation Match Points to Generate a Digital Elevation Model OrthoEngine uses the math model solution known exterior orientation and the pixel and line positions of the points in common in the overlapping images to generate a digital elevation model DEM
135. e the Number of Looks to estimate noise variance and to control the amount of smoothing applied to the image In theory the correct value for the Number of Looks should be the effective number of looks of the radar image or close to the actual number but it may be different if the image was resampled Using a smaller value for the Number of Looks leads to more smoothing and a larger value preserves more image features In the No of Looks list select the Number of Looks that you want to apply to the image OrthoEngine User s Guide 109 Chapter 8 Correcting Your Images Radar Enhanced Lee Filter The Radar Enhanced Lee Radar Enh_Lee Filter resampling option determines the gray level for each pixel by computing the weighted sum of the center pixel value the mean value and the variance calculated in a square frame surrounding the pixel To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data This filter is used primarily to suppress speckle It smooths image data without removing edges or sharp features in the images while minimizing the loss of radiometric and textural information In homogeneous areas speckles are removed using a low pass filter In heterogeneous areas speckles are reduced while preserving the texture In areas containing isolated point targets the filter preserves the observed value The resulting gray level value R for the smoothed pixel is
136. e up to 3 to 4 meter accuracy by adding one or two quality GCPs for each image fex step in your project See Setting the Projection on page 13 Starting a Project Using the Polynomial Math Model The Polynomial Math Model is a simple math model that produces the best mathematical fit to a set of two dimensional ground control points GCPs For more information see Understanding the Polynomial Math Model on page 7 To start the project 1 On the OrthoEngine window in the File menu click New 2 On the Project Information window in the Filename box type a file name for your project 3 In the Name box type a name that you want to appear on the title bar of the OrthoEngine window 4 In the Description box type a description of the project that will help you to identify its contents 5 Under Math Modelling Method click Polynomial 6 Click Accept OrthoEngine User s Guide 11 Chapter 2 Starting your Project and Selecting a Math Model Ho step in your project See Setting the Projection on page 13 Starting a Project Using the Thin Plate Spline Math Model The Thin Plate Spline Math Model is a simple math model in which all the collected ground control points GCPs are used simultaneously to perform a transformation For more information see Understanding the Thin Plate Spline Math Model on page 8 To start the project 1 On the OrthoEngine window in the File menu click
137. e values The Elevation Offset is used to add a value to the pixel values in a DEM to obtain their actual elevation value Using the same example perhaps the DEM pixel with a value of 102 actually represents an elevation value of 1 102 To store the elevation values in an 8 bit channel 1 000 was subtracted from all the pixel values when the DEM was created Therefore you must type 1 000 in the Elevation Offset box to restore the true values You can also use Elevation Offset to adjust the elevation reference of a DEM The elevations in a DEM can be calculated above Mean Sea Level or an ellipsoid The elevation reference in the DEM must match the elevation reference ofthe imagery that you want to orthorectify To compensate for a discrepancy you can type the difference between the two elevation references in the Elevation Offset box You can also convert the DEM see Converting the DEM Datum on page 126 The Elevation Scale and Elevation Offset can be used together to convert the DEM pixel values to their actual elevation values The equation for the conversion is elevation Scale DEM pixel value Offset Continuing the same example if you add the DEM pixel value to the Elevation Offset 102 1 000 and multiply the result by the Elevation Scale 1 102 0 1 then the DEM pixel value actually represents an elevation value of 110 2 2 s Tip If you do not have a DEM you can use the average elevation of an area to orthore
138. ecentering Distortion on page 22 Defining Photo Scale on page 23 Defining Earth Radius on page 23 Defining Fiducial Marks on page 23 Defining Chip Size and Y Scale Factor on page 24 Defining Focal Length The Focal Length is the distance between the focal point of the lens and the film Entering an incorrect focal length may introduce unwanted distortions in your project To enter this compulsory parameter see Entering the Camera Calibration Data on page 24 Figure 4 1 Effect of focal length on computed position of the camera image plane film lens incorrect focal length B focal point ground The result 1s a difference in A the relationship between the image and the ground and B in the computed position of the camera 21 Chapter 4 Setting Up Camera Calibration and Aerial Photographs Defining Principal Point Offset The Principal Point is the point on the image where a ray of light travelling perpendicular to the image plane passes through the focal point of the lens and intersects the film In a perfectly assembled camera the principal point would be where the lines of opposing fiducial marks on an photograph intersect However in most cameras a slight offset occurs The perspective effects in the image are radial about this point This parameter is optional but the offsets are usually specified in the camera calibration report To enter the Principal Point Off
139. eck Point 59 change type of vectors 88 Changing the channel display Chip Manager 137 channel display Chip Manager 137 channel selection 43 123 Channels 16 Bit Signed 112 129 16 Bit Unsigned 112 129 32 Bit Real 112 129 8 Bit Unsigned 112 129 Average Image 124 block averaging 124 change color 123 Database Channels 123 selecting 123 set channel type 129 Character descriptions 133 characters 60 Charged Coupled Devices See CCDs Check Point 36 38 39 41 47 59 Check Points 57 chip 40 Chip Cursor Color Chip Manager 141 chip database 40 135 Chip GCP Color Chip Manager 141 chip ID 41 Chip Information 24 Chip Manager 135 chip sequence number 41 Chip Size 24 137 138 choosing quality tie points 52 Clear Mask 76 Cliffs 2D 66 Clip Region 30 72 for extracting lines from DEM 96 for geocoding DEM 80 Cloud Covered Areas 79 coefficients Decentering Distortion 24 extract from file 11 Radial Lens Distortion 22 24 Rational Functions 7 collect a chip from an image 137 collect GCPs from chip database 40 from chip database automatically 43 from geocoded image 37 from tablet 45 47 from vectors 39 manually 36 collect tie point automatically 53 OrthoEngine User s Guide 145 collect tie point manually 52 collecting cutlines 114 115 color balancing automatic 114 manual 116 understanding 117 Colors Chip Manager 141 command string for tablet 49 60 communication with tablet 46 49 60 computation of a r
140. ed images For more information about the status displayed in the Geometric Corrected Image Production window see Understanding the Status Descriptions on page 103 To start processing your image l On the OrthoEngine window in the Processing Step list select Geometric Correction Click P the Schedule Geometric Correction icon Under Available Photos select the images that you want to process and click the arrow button to move the images under Photos to Process 10 The images are processed in the order that they appear under Photos to Process If you have already corrected the image Delete existing file appears next to the image When the image is processed the previous version is replaced If you have not corrected the image previously Create new file appears Under Photos to Process select an image In Input Channels click All to select all the image channels or click Channels and type the channels that you want in the Channel box You can use a dash between the channel numbers to indicate a range and a comma between individual channel numbers Repeat step 5 for the remaining images or select Apply input channel selection to all files to use the same channel selection for the remaining images You can delete the uncorrected image from the disk when the process is complete Select an image under Photos to Process and select Delete input file when done Repeat for each image that you want to delete after the
141. ed on orbital information instead of ground control points the RADARSAT Specific Model and the Rational Functions model when it is used with the IKONOS GEO Ortho Kit product Orbit information is always referenced to an ellipsoid and the ellipsoid number is taken from the projection information defined in the file A DEM extracted from satellite imagery using the above math models is based on an ellipsoidal model of the earth not the geoid The difference between elevations relative to the ellipsoid and those relative to the geoid can be significant up to 107 meters in some areas Therefore you must make sure that the elevation reference ofthe DEM matches the elevation reference of the imagery To perform a conversion between Ellipsoid and MSL OrthoEngine calculates the difference between the geoid and the ellipsoid at the point in question and then applies the difference to compute the transformed elevation To convert the DEM datum 1 In the main menu click Utilities 2 Click Convert DEM Datum 3 In DEM File type the path for the DEM or click Browse to select the file 4 Click Channel and select channels from the list or click All Channels 5 Click Ellipsoidal to MSL to convert the Ellipsoid elevations to Mean Sea Level elevations MSL to Ellipsoidal to convert the Mean Sea Level elevations to the Ellipsoid elevations 6 In Skip Value type the number that you do not want converted such as the background v
142. egment and click Load or Load amp Close To hide a vector layer Check marks under Show indicate visible vector layers To hide a vector layer click under Show to remove the check mark 122 PCI Geomatics Cursor Control Changing the Color of a Vector Layer To change the color of the vectors 1 Click under Color beside the layer that you want to change 2 Select one of the following to choose a color Click a color under Basic Colors Click a color under Color Continuum Inthe Model list select a color model and adjust the color values as required Each color model offers different color values For Gray type or select the gray level For RGB type or select the red green and blue values For CMYK type or select the cyan magenta yellow and black values For HLS IHS type or select the hue lightness and saturation values 3 Under Intensity move the slider to determine the strength of the color 4 Click OK Cursor Control To place your cursor al 1 Click the Open new or existing photo icon For information how to open an image see Opening Images on page 17 2 Click the X Cursor Control icon 3 Youcan Click in the viewer to view the coordinates in the Cursor Control window Type new pixel P and line L coordinates under Raster The cursor will move to that exact location in the viewer Type new coordinates under Geocoded or User Defined Projection The cursor wi
143. eighbors in the frame The Damping Factor specifies the extent of the damping effect of filtering OrthoEngine uses a default value of 1 since it is sufficient for most SAR images The resulting gray level value Rf for the smoothed pixel is Rf P1 M1 P2 M2 Mn where Pn Mn Ml M2 P1 Pn are gray levels of each pixel in frame MI Mn are weights as defined above for each pixel The Number of Looks and the Image Format of the radar image are usually recorded on the CD jacket or magnetic tape label or in the format specifications provided by the data vendor Filter Size The frame is circular with its width and length in odd numbers You control the size of the frame with the Filter Size option by typing the number of pixels width in the X box and the number of lines length in the Y box Different filter sizes greatly affect the quality of the processed images If the filter is too small the noise filtering algorithm is not effective If the filter is too large subtle details of the image are lost in the filtering process The minimum size for the frame is 3 by 3 pixels A 7 by 7 frame usually gives the best results Image Format The radar images are supplied in one of two Image Formats Power or Amplitude Power is the sum of the squares of the real and imaginary values of the complex pixel values in the radar image Amplitude is the square root of Power Most radar images are supplied in the Amp
144. el values in the radar image Amplitude is the square root of Power Most radar images are supplied in the Amplitude format to preserve the values You identify the format used with your images in the Image Format list Number of Looks You use the Number of Looks to estimate noise variance and to control the amount of smoothing applied to the image In theory the correct value for the Number of Looks should be the effective number of looks ofthe radar image or close to the actual number but it may be different if the image was resampled Using a smaller value for the Number of Looks leads to more smoothing and a larger value preserves more image features In the No of Looks list select the Number of Looks that you want to apply to the image 110 PCI Geomatics Mosaicking Your Images Understanding Mosaicking Mosaicking is joining together several overlapping images to form a uniform image as shown in Figure 9 1 Basically it is similar to creating a jigsaw puzzle with your images and then making the joints disappear For the mosaic to look like one image instead of a collage of images it is important that the images fit well together You will achieve better results if you orthorectify your images Using a rigorous math model ensures the best fit not only for the individual images but for all the images united as a whole For more information see Starting your Project and Selecting a Math Model on page 5 and Correc
145. elevation model DEM to the ground coordinate system at a given ground resolution Quote If you selected Create Geocoded DEM on the Automatic DEM Extraction window your epipolar DEMs are already geocoded To geocode the extracted DEM 1 On the OrthoEngine window in the Processing Step list select DEM From Stereo 2 Click Al the Geocode Extracted DEM icon 3 Under Input DEM in the File box type the path where the extracted epipolar DEM is found or click Browse to select the file 4 Inthe DEM Channel list click the DEM channel or click Select to view the choices and choose a channel OrthoEngine User s Guide 79 Chapter 6 Generating Digital Elevation Models 3 10 11 In the Failure Value box type the value used to represent the failed pixels in the input DEMs In the Background Value box type the value used to represent the background The background identifies the pixels that lie outside the DEM so they are not mistaken for elevation values Under Input Window click Full Image to geocode the entire DEM Window to geocode a specific area of the DEM In the Offset boxes type the pixel and line coordinates of the upper left corner of the area In the Size boxes type the number of pixels and lines to specify its size Under Output DEM in the File box type the path where the geocoded DEM is saved or click Browse to select a location Inthe Pixel Spacing box type the output pixel si
146. en you do not have the whole image The Rational Functions Math Model can be more accurate than the Polynomial or Thin Plate Spline Math Models since it considers elevations However it can require many ground control points GCPs The math model is computed for each image separately The Rational Functions Math Model uses a ratio of two polynomial functions to PCI Geomatics Understanding the Math Models compute the image row and a similar ratio to compute the image column All four polynomials are functions of three ground coordinates latitude longitude and height or elevation The polynomials are described by using a set of up to 20 coefficients although some of the coefficients are often zero The polynomial coefficients often called Rapid Positioning Capability RPC data can be obtained in two ways You collect a number of GCPs and OrthoEngine calculates the polynomial coefficients automatically The minimum number of required GCPs is determined by multiplying the number of coefficients by 2 and then subtracting 1 For example if you wanted to use 10 coefficients you would multiply 10 by 2 and then subtract 1 which means you would need 19 GCPs per image You set the number of coefficients that you want to use on the GCP Collection windows under Auxiliary Information see Collecting Control Points and Computing the Math Models on page 33 The image distribution agency computes the polynomial coefficients f
147. end that you accept the default projection Changing the projection will cause OrthoEngine to re project the file on the fly which can significantly hinder the performance L Make sure you save your project and layers before attempting to add a layer with a different projection To change the projection Type the projection string for example UTM 17 T D000 in the text box beside the Earth Model button If you do not know the projection string 1 Select a projection type from the list under Georeferencing Info For UTM State Plane Coordinate Systems SPCS or Other projection types additional windows may open automatically for you to select the parameters to define the projection or click More to open these windows Select the parameters and click Accept 2 Click Earth Model 3 Click either the Datum or Ellipsoid tab 4 Click a datum or an ellipsoid 5 Click Accept 86 PCI Geomatics Loading a Layer Loading a Layer You can import existing vector layers into your project The files containing the vector layers can be from any of the supported file formats To import the vector layer 1 Click Load Layer 2 Select the file and click Open 3 Select the layer and click Load or Load Close The added layer becomes the active layer in the viewer fes step in your project See Adding Points to a Layer on page 88 Adding Lines to a Layer on page 88 and Adding Polygons to a Layer on
148. ennen nennen enne 55 Performing the Bundle Adjustment for Rigorous Math MoOdelS ooooocioncconnocccncnonnnooncconnoncnnnnn non nnn conan nennen nennen rre 55 Understanding the Solution for Simple Math Models seessseeseeee cnn no nor nnn carne 56 Troubleshooting the Math Model Solution xoommiiinii a a a a a a a a 56 Identifying Errors in the Math Model 25 5 aiii a tht 57 iii Generating a Residual Report s di 58 Editing Points inithe Residual Report cit iR Rn ie meet uisu diae neum 59 Defining the Tablet Format Strings aaa 60 Chapter 6 GENERATING DIGITAL ELEVATION MODELS Understanding Digital Elevation Models 5 2 3 2 2 eite AA oet olere ede dox A 63 Using Rasters to Generate a Digital Elevation Model sesseseeeeeeeene nennen rre rn rene nennen nne enne nn 64 Using Ground Control Points Tie Points and or Elevation Match Points to Generate a Digital Elevation Model ssesssss 64 Using Vectors to Generate a Digital Elevation Model sssssssseene eene nr nn nn 65 Generating the Digital Elevation Model from Rasters Vectors or Control Points ooooocccnnccccccnnnococccnccnonancnncnnnnnncnnnnnnn nn cnc enne nennen nn nnns 67 Understanding the Interpolation Methods for Vectors ssssssssssseeseeeene enne enne nennen enne innere erret nnne n EAEE nnns 68 Building a Digital Elevation Model
149. eport provides information such as creation date and time date and time of the last update database name and the number of chips of each type of sensor in the database To produce a report 1 Open a database For more information see Opening an Existing Chip Database on page 136 2 Inthe main menu click Utilities 3 Click Reports 4 Click Current Chip to produce a report about the displayed chip Summary to produce a report about the chip database 5 Click Close to close the report without saving it Save to File to save the report in a text file Setting the Source Image Default Parameters If you are going to create many chips from the same image you can enter defaults in the Default Parameter Settings window 140 PCI Geomatics Changing the Colors of the Cursors To set the defaults 1 From the main menu click Preferences and click Default 1 2 Inthe Sensor box type the name of the sensor or select the sensor 2 from the list 3 Inthe Viewing Angle box type the angle in degrees between the axis 3 of the sensor and the ground 4 Inthe Acquisition Date box type the day month and year that the image was taken 4 5 Inthe Resolution boxes type the x pixel size and the y pixel size in the units used in the image 6 Inthe General Description box type a description that will help you identify the chip 7 Inthe Scene Description box type the Scene ID 8
150. erial camera or satellite at the time when the image was taken Once the position and orientation of the sensor is identified it can be used to accurately account for known distortions in the image In the Aerial Photography math model the geometry of the camera is described by six independent parameters called the elements of exterior orientation The three dimensional coordinates x y and z of the exposure station in a ground coordinate system identify the space position of the aerial camera The z coordinate is the flying height above the datum not above the ground The angular orientation of the camera is described by three rotation angles Omega Phi and Kappa For more information on exterior orientation see Understanding Exterior Orientation on page 26 In the Satellite Orbital math model the position and orientation of the satellite is described by a combination of several variables of the viewing geometry reflecting the effects due to the platform position velocity sensor orientation integration time and field of view The bundle adjustment uses ground control points GCPs and tie points combined with the knowledge of the rigorous geometry of the sensor to calculate the best fit for all images in the project simultaneously For Aerial Photography projects the bundle adjustment can only be computed after you collect the minimum number of ground control points GCPs and tie points If you are using data from the Glob
151. eseeene cnn non cnn nr 15 Reading Satellite Images from a CD or a Digital Distribution Format ssesseseeeeeene emen eene nnnm rennen nennen nene nennen 15 Reading Satellite Data from a Tape ierant aiii cid 16 Reading Satellite Data from a Generic Image File eene nene rren nnne ener enenr nennen nennen tenere enne 17 Importing Satellite Data from a PCIDSK File onere E ritenere di ici 17 Openirig Images 3 ien pde e eer ire rad 17 Supported Satellite Formats viii M 18 Chapter 4 SETTING UP CAMERA CALIBRATION AND AERIAL PHOTOGRAPHS Understanding Camera Calibration Data s site inisini ssepe dene d deca dre ed ated eo ene oen decade edad re doe d odia eve d da ed spe een 21 Defining Focal Ent ED 21 Defining Principal Point Osetia 22 Defining Radial Lens DIStOrtiOri 2 1 2 ca ttn intere iii 22 Defining Decentering Distortion 4 2 22 2 a e IS efe Feste re Be Rud li deae qe ce beet etes mee det Eee sete e dead pas 22 Defining Photo Scale oer Ret aa 23 Defining Earth RadiUS Pc N a 23 Defining Fiducial Marks 22 0 3 23 A eee nne 23 Defining Chip Size and Y Scale Facto ea 24 Entering the Camera Calibration Data sese enne nnne RR enn 24 Collecting Fiducial Marks Manually onere oO uri s idea 25 Collecting Fiducial Marks Automatically a rn 26 Un
152. evel value R for the smoothed pixel is R IC W Im 1 Ww where W 1 Cu 2 Ci 2 1 Cu 2 Cu SQRT 1 Number of Looks Ci S Im Ic center pixel in the frame Im mean value of intensity within the frame S standard deviation of intensity within the frame The Number of Looks and the Image Format of the radar image are usually recorded on the CD jacket or magnetic tape label or in the format specifications provided by the data vendor Filter Size The frame must be square with its width and length in odd numbers You control the size of the frame with the Filter Size option by typing the number of pixels width in the X box and the number of lines length in the Y box Different filter sizes greatly affect the quality of the processed images If the filter is too small the noise filtering algorithm is not effective If the filter is too large subtle details of the image are lost in the filtering process The minimum size for the frame is 3 by 3 pixels A 7 by 7 frame usually gives the best results Image Format The radar images are supplied in one of two Image Formats Power or Amplitude Power is the sum of the squares of the real and imaginary values of the complex pixel values in the radar image Amplitude is the square root of Power Most radar images are supplied in the Amplitude format to preserve the values You identify the format used with your images in the Image Format list Number of Looks You us
153. f all pixels in a square or rectangular frame surrounding the input coordinates and assigns the value to the output coordinates The median is obtained by ranking the gray levels according to brightness and determining the middle value To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data This method smooths the appearance of the image You control the size of the frame with the Filter Size option by typing the number of pixels in width in the X box and the number of pixels in length in the Y box Gaussian Filter The Gaussian Filter resampling option determines the gray level from the weighted sum of all the pixels in a square or rectangular frame surrounding the input coordinates and assigns the value to the output coordinates To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data The filter weights are computed using a Gaussian function G i j expC CCi u 2 j v 2 2 Gaussian SQ where i j is a pixel within the frame and Gaussian SQ is the square of the Gaussian distribution deviation You control the size of the frame by typing a value between 1 0 and 32 0 in each of the Gaussian SQ boxes The filter weights W i j are the normalized values of G i j in the frame The sum of all the weights is 1 The gray level of a filtered pixel is the sum of W i j V j over all pixels in the frame where
154. ferent from image to image Understanding Color Balancing Radiometric differences between images can cause a patchwork effect in a mosaic Color balancing evens out the color contrasts from one image to another to reduce the visibility of the seams and produce a visually appealing mosaic Applying Color Balancing during Automatic Mosaicking When you select Entire Image OrthoEngine builds histograms for each image determines the optimum radiometry for the final mosaic and applies the transformation starting from the center of the mosaic When you select Overlap Area OrthoEngine generates histograms for all the overlapping areas in the mosaic performs a least squares analysis to determine the optimum radiometry for the final mosaic and then builds a transformation for each image as it is added to the mosaic Applying Color Balancing during Manual Mosaicking The color balancing in Manual Mosaicking is based on the samples that you identify in the overlap between the images already mosaicked and the image that you are adding to the mosaic OrthoEngine uses these samples match areas to compute a lookup table that will adjust the color in the image that you are adding to match the images already mosaicked Collect small match areas representing the different areas so the lookup table can be used to accurately correct radiometric mismatches For example collect a match area in green area to balance greens a match area in dark area t
155. ffects and the camera s position and orientation The computed math model calculates the camera s position and orientation at the time when the image was taken You should not use the Aerial Photography Math Model when you are using only a portion of the original image when the image has been geometrically processed or when you do not have or cannot estimate the camera calibration information Understanding Satellite Orbital Modelling The Satellite Orbital Math Model is a rigorous model developed by Dr Toutin at the Canada Center for Remote Sensing to compensate for distortions such as sensor geometry satellite orbit and attitude variations and earth shape rotation and relief This model can be applied to ASTER AVHRR IKONOS LANDSAT SPOT IRS QuickBird and radar images such as ASAR beta support RADARSAT ERS 1 and JERS1 The computed math model calculates the position and orientation of the sensor at the time when the image was taken Chapter 2 Starting your Project and Selecting a Math Model For IKONOS images also see Using the Right Math Model with IKONOS Data on page 6 You should not use the Satellite Orbital Math Model when you are using only a portion of the original image when the image has been geometrically processed or when you do not have or cannot estimate the orbit information The Satellite Orbital Math Model is based on the co linearity condition which represents the physical law of t
156. final DEM relative to the input images The higher the number you choose the larger the DEM pixel will be and the faster the DEM is processed Figure 6 4 Explaining Pixel Sampling The shaded area becomes one epipolar DEM pixel raw image Pixel Sampling of 2 uH He If the Pixel Sampling is 2 then the DEM file is divided as follows raw image DEM file dB HH Depending on the results you are looking for you can use different Pixel Sampling of 4 combinations of these two features For example you may want to have A low resolution DEM high numbered Pixel Sampling if the terrain is fairly flat but retain high precision for the pixel values in the DEM high DEM Detail A high resolution DEM low numbered Pixel Sampling if your imagery is coarse such as SPOT or RADARSAT data and select low DEM Detail to speed up the process or produce a smooth DEM A full resolution DEM Pixel Sampling of 1 for aerial photographs which would contain very fine features such as light posts and bushes but need a smoother DEM that represents the terrain better low DEM Detail Opening the Digital Elevation Model Editing Windows To open the DEM editing windows 1 On the OrthoEngine window in the Processing Step list select Import amp Build DEM or DEM From Stereo 2 Click S the Manually edit generated DEM icon 3 Onthe Image DEM File window click the DEM file and click Open 4 Onthe File window under Dat
157. for NLAPS is the file that contains hl h2 Or h3 MERIS ENVISAT MERIS 1B format QUICKBIRD TIFF NITF QUICKBIRD provides different levels of processing The following formats are recommended Basic product in GeoTiff Basic product in NITF format QUICKBIRD standard product is already corrected using GTOPO30 DEM therefore is not recommended We will re evaluate the product when the GTOPO30 DEM correction is no longer applied RADAR CEOS ERS data ERS CD provides different levels of processing We recommend the georeferenced level for images produced in Canada and the PRI level produced by ESA RADAR CEOS RADARSAT SGC SAR Georeferenced Coarse Resolution SGF SAR Georeferenced Fine Resolution SGX SAR Georeferenced Extra Fine Resolution SLC Single Look Complex SCN ScanSAR Narrow Beam Product SCW ScanSAR Wide Beam Product p quote SCN and SCW data is rotated top to bottom for ascending path imagery or left to right for descending path imagery Therefore the upper left corner of the image is the north west corner like the single look products If the imagery is flipped this action is printed to the terminal and REPORT SPOT 1 to 3 LGWOWG Canadian format The Canadian LGSOWG CD provides different levels of processing OrthoEngine only supports the level 1 CD Level 1 is radiometrically corrected with detector offsets applied SPOT 1 to 4 SPOTIMAGE The SPOTIMAGE LGS
158. from a Stereo Pair of Images sss enne ennemi nnne nennen nne enne 69 Creating Epipolar Imag85 nea i een ah ERR e en e E e e rece ee ai ees 69 Extracting Digital Elevation Models from Epipolar Pairs eessseeee eene e enne enn nennen rene nennen nennen 71 Understanding Pixel Sampling and DEM Detail seen enne nnnm enr en nnne nnne n enn en ern n neret nennen nennen nennen 73 Opening the Digital Elevation Model Editing Windows sese enne rre 74 Switching Between the Image Channel and the DEM ssssssssseeeneeenee enm ene rennes ernst erret nens sen nnne nennen nenne en nennen nne 75 Editing the Digital Elevation Model eoe i R A aa 75 Creating a Mask ii ee Pee ee ie Ee ee Ae A 75 Replacing the Elevation Values Under a Mask sse nene nenne nennen tadaa tre en teneret nere enn et ern ennnr nennen nnns 76 Bulldozing aiLine ERE LP eee ee een Ge ee ee a en se M 77 Filtering and Interpolatirig 2 2 tes A ai 77 Applying Tool Strategies for Common Situations in Digital Elevation Models senem nre nnnm 78 Equalizing Pixel Values for Lake Sis oros it td ad CE NERIS 78 Compensating for Forests and Urban Areas umi a tata 78 Neutralizing Clo d Covered Area oi AA ceda pate Bret ve cbe nue res 79 De ling With NOISE qc 79 Geocoding a Digital Elevation Model c
159. gital Image Enhancement and Noise Filtering by Use of Local Statistics IEEE Transactions on Pattern Analysis and Machine Intelligence Vol PAM 1 2 No 2 March 1980 J S Lee Refined Filtering of Image Noise Using Local Statistics Computer Graphic and Image Processing 15 p 380 to 389 1981 D T Kuan A A Sawchuk T C Strand and P Chavel Adaptive restoration of images with speckle IEEE Trans ASSP Vol 35 no 3 pp 373 to 383 March 1987 A Lopes R Touzi and E Nezry Adaptive speckle filters and Scene heterogeneity IEEE Transaction on Geoscience and Remote Sensing Vol 28 No 6 pp 992 to 1000 Nov 1990 V S Frost J A Stiles K S Shanmugan and J C Holtzman A model for radar images and its application to adaptive digital filtering of multiplicative noise IEEE Trans Pattern Analysis and Machine Intelligence vol 4 no 2 pp 157 to 166 March 1982 A Lopes E Nezry R Touzi and H Laur Structure detection and statistical adaptive speckle filtering in SAR images International Journal of Remote Sensing Vol 14 No 9 pp 1735 to 1758 1993 A Lopes R Touzi and E Nezry Adaptive speckle filters and Scene heterogeneity IEEE Transaction on Geoscience and Remote Sensing Vol 28 No 6 pp 992 to 1000 Nov 1990 Zhenghao Shi and Ko B Fung 1994 A Comparison of Digital Speckle Filters Proceedings of IGARSS 94 August 8 12 1994 Nearest Nearest Neighbor Interpo
160. h are two or more images of the same area taken from different view points This method can be very useful for creating a DEM for inaccessible areas You can obtain stereo pairs from aerial photographs digital or video images and these sensors ASAR ASTER IRS IKONOS SPOT QUICKBIRD and RADARSAT 2 Tip To help you select a RADARSAT stereo pair CCRS provides an interactive Web tool See http www pcigeomatics com support FAQ oe data htm OrthoEngine uses image correlation to extract matching pixels in the two images and then uses the sensor geometry from the computed math model to calculate x y and z positions Figure 6 1 Creating a DEM from stereo pairs matching pixels right image the x y and z aet position DEM pixel values representing the elevation rw step in your project See Creating Epipolar Images on page 69 Creating Epipolar Images Epipolar images are stereo pairs that are reprojected so that the left and right images have a common orientation and matching features between the images appear along a common x axis Using epipolar images increases the speed of the correlation process and reduces the possibility of incorrect matches Figure 6 2 Comparing raw images to epipolar images raw images I Ll Y To create epipolar images 1 On the OrthoEngine window in the Processing Step list select DEM From Stereo 2 Click on the Create Epipolar I
161. h pixel by computing a set of weighted values in a square frame surrounding the pixel To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data This filter is used primarily to suppress speckle It smooths image data without removing edges or sharp features in the images You can use this filter for a wide range of Gamma distributed images such as those containing forested areas agricultural lands and oceans The filter also preserves the observed pixel value for non Gamma distributed images The Gamma filter minimizes the loss of texture information since it uses the statistical properties of the underlying image Assuming a Gamma distributed image the resulting gray level value R for the smoothed pixel is R Im for Ci lt Cu R Rf for Cu lt Ci lt Cmax R Ic for Ci gt Cmax where Rf B Im SQRT D 2 A Ci Im Cu SQRT 1 Number of Looks Cmax SQRT 2 Cu Im mean value of intensity within the frame S standard deviation of intensity within the frame Ic center pixel in the frame A 14 Cu 2 Ci 2 Cu 2 B A Number of Looks 1 D Im Im B B 4 A Number of Looks Im Ic The Number of Looks and the Image Format of the radar image are usually recorded on the CD jacket or magnetic tape label or in the format specifications provided by the data vendor Filter Size The frame must be square with its width and length in odd numbers You contro
162. he Clip Region see Defining a Clip Region on page 30 Select Fill Holes And Filter if you want to enhance the output quality of the DEM by interpolating the failed areas and filtering the elevation values automatically Select Create Score Channel if you want to generate an additional image channel to represent the correlation score for each DEM pixel The correlation score will help you to identify pixels where correlation to the ground was weak or failed which gives you a truer impression of the success of the operation 72 PCI Geomatics Understanding Pixel Sampling and DEM Detail 13 Select Delete Epipolar Pair After Use if you want to delete the epipolar pairs from the disk to save space after the DEM is generated 14 Under Geocoded DEM select Create Geocoded DEM if you want to geocode and merge the epipolar DEMs However if you want to edit the DEM before it is geocoded DO NOT select Create Geocoded DEM and skip to step 19 15 To save space you can select Delete Epipolar DEM After Use to delete the epipolar DEM from the disk after the geocoded DEM is generated 16 In the Output Filename box type the path for the geocoded DEM file or click Browse to add it to an existing geocoded DEM file 17 To determine the extents of the DEM select one of the following In Upper Left Lower Right and Resolution type the new values in the X and Y boxes that you want to change n DEM Bounds click All P
163. he Processing Step list select 3 D Operations EN 2 Click au the 3 D feature extraction icon iS 3 On the 3 D Stereo Pair Selection window under Project Pair Overview click the crosshairs of the image that will be displayed to your left eye All the crosshairs of the images that overlap the selected image appear in blue under Stereo Pair Detail 4 Under Stereo Pair Detail click the crosshairs of the overlapping image that will be displayed to your right eye 5 Click Uncorrected Image to select the raw images or click Epipolar Image to select an epipolar pair If epipolar images exist for the pair that you selected the option Epipolar Image will become available Using epipolar images while editing in 3 D stereo produces a sharper stereo view over the entire area of the image and reduces the need to manually align the images For more information see Creating Epipolar Images on page 52 6 Inthe Stereo Mode list click the type of viewing display that you are using OrthoEngine will automatically search for the OpenGL libraries but will not confirm the presence of the required stereo viewing hardware If the OpenGL libraries are present both Anaglyph and OpenGL options will be available Click Anaglyph to display the one image in red and the other in blue To view the images in 3 D you must wear a pair of 3 D glasses which has one red lens and one blue lens OpenGL to display in a single window the images
164. he image OrthoEngine User s Guide 27 Chapter 4 Setting Up Camera Calibration and Aerial Photographs Importing GPS INS or Exterior Orientation Data from a Text File OrthoEngine will only extract the entries from the text file that match the photo IDs from the entries in the project For more information about exterior orientation see Understanding Exterior Orientation on page 26 To import GPS INS or Exterior Orientation l On the OrthoEngine window in the Processing Step list select Data Input Click pe the Import GPS INS or exterior orientation data from file icon If you chose Compute from GCPs and Tie Points when you started your project the Import GPS INS Data from Text File window opens If you chose User Input when you started your project the Import Exterior Orientation Data from Text File window opens In the File Format list click the string that represents the layout of the data in the text file For example the string PhotoID X Y Z represents the layout The first column is the photo ID number the second column is the x coordinate the third column is the y coordinate and the fourth column is the z coordinate Estimated errors in the coordinates and the orientation are represented by values such as eX eY eZ and so on A forward slash represents a new line In Angle Unit select the unit for the orientation angles that are used in the text file Click Degree if the file exp
165. hipMarnaget sinisi enr eie tee A ii a 135 eror Toleto Rer 135 Creating a New Database iiir tL Epod Led ati iii 135 Opening an Existing Chip Database ii idas 136 Selecting thie Source forthe Chips 1 3 2 ii a 136 Working in the Chip Manager Viewers 1er cae 137 Collecting the Chip iio boat 137 Determining the Size of the Chip iii i n 137 Creating Chips froma GCP Semen tad 138 Changing the Location of the CP aiii 138 Searching the Chip Database sssrini tnasa tt hai 139 Creating a New Chip Database from an Existing Database sssssssesseeeeeeeeneeeenenen ene nheee nennen nennen nene entren nr een nnne enne 139 Merging Chip Databases n pode stel i P Seide SU T eode eru ett d ege eoa ice Nested be ct 139 Deleting a Chip Database E 139 Deleting a Chip trom the Database cuicos idea 140 Defragmenting a Chip Database ited e ed t d esc aioe eel aa deter pete ede ies 140 Generating Reports 3 idi eub A A Da Ar RUD IE P i o edna atl 140 Setting the Source Image Default Parameters sssssssseseseeeeneen nennen rr 140 Changing the Colors of the GUISOS uc at ettet Ep Lote Ego ed ec Pene de zuo dine e ecu dee eden iden 141 O A ER 143 viii Using OrthoEngine Introducing Geomatica OrthoEngine Welcome to Geomatica OrthoEngine OrthoEngine is a powerful photogrammetric tool designed to handle small and large production workloads to efficiently produce quality geospatial products
166. hotos to use the extents of all the images in the Stereo Pair Selection table as the extents for the DEM or click Selected Photos to use only the extents of the images checked under the Select column Click Recompute to recalculate the extents 18 As the epipolar pairs are generated and geocoded they are added to the geocoded DEM file When a new geocoded DEM is added to the file and it overlaps an existing geocoded DEM you must choose a method to determine which pixel value will be used In the Output Option list click Use Last Value to replace the pixel values in the overlap area in the existing geocoded DEM by the pixel values of the geocoded DEM being added to the file Average to replace the pixel values in the overlap area by the average pixel values between the existing geocoded DEM and the one being added to the file Highest Score to replace the pixel values in the overlap area by the pixel value with the highest correlation score between the existing geocoded DEM and the one being added to the file This option is only useful if you select Create Score Channel 19 Under Extraction Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours 20 Click Start DEM Extraction 21 Click Close fex step in your project To edit the DEM see Opening the Digital Elevation Model Editing Windows on page 74 Understanding Pixel Sampling and DEM
167. ic not available in Mosaic Only projects In the Mosaic Pixel Spacing box type the x pixel size In the Mosaic Line Spacing box type the y pixel size Changing the resolution for the mosaic also changes the resolution in the Set Projection window 5 Ifavailable you can select Regenerate stale orthos to update any images labelled Stale in the Status column 6 Ifavailable you can select Delete newly generated orthos after use to save disk space 7 lfavailable you can click to remove the check mark beside Clear mosaic file before starting to mosaic to add the images selected in 118 PCI Geomatics Mosaicking Digital Elevation Models the Use column to the existing mosaic file To delete the images in the mosaic file and reset the background to the default before adding the selected images select Clear mosaic file before starting to mosaic 8 Under Processing Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours 9 Click Generate Mosaic Mosaicking Digital Elevation Models Although you can use Automatic Mosaicking to unite digital elevation models DEMs using DEM from raster file is designed specifically for this purpose For more information about using DEM from raster file see Using Rasters to Generate a Digital Elevation Model on page 64 If you do decide to use Automatic Mosaicking set Color Balance to None and choose Min
168. ich shortens the process for Automatic DEM Extraction and 3 D Feature Extraction Automatic DEM Extraction can start batch processing for the epipolar pairs and generate and automatically geocode a single seamless DEM in one process Selecting multiple images to orthorectify or geometrically correct streamlines the process Chapter 1 Using OrthoEngine Improved color balancing in Automatic Mosaicking reduces the need to refine the results Getting Started The work flow that you choose depends on what you want to achieve If you have a clear idea of what you want to obtain from your project it will be easier to work through your project and achieve the results that you want When you start a project l Determine the accuracy and resolution requirements for your project Knowing the level of accuracy that you want to obtain the resolution of your deliverable final output the file size limitations and the extent of your budget will help you to make the right decisions about how you build your project Determine your deliverable What do you want as the end result of your project OrthoEngine can Orthorectify images Orthorectified images Orthos are geometrically corrected and georeferenced imagery Orthorectification is the process of using a rigorous math model and a digital elevation model DEM to correct distortions in raw images For more information see Understanding Orthorectification on
169. iety of products but does not release the orbit data Their most economical product IKONOS GEO is a simple image file with positional accuracy of up to 150 meters not including terrain effects To orthorectify IKONOS GEO images use the Satellite Orbital math model which provides 3 to 4 meter accuracy with the collection of 20 or more ground control points GCPs Space Imaging s IKONOS GEO Ortho Kit product is a Geotiff combined with a text file that contains rational function coefficients called Image Geometry Model IGM or Rapid Positioning Capability RPC The Ortho Kit product also contains no orbit data but the text file provides the coefficients to define the Rational Functions math model Using the Rational Functions math model with the Geotiff and the text file provides 10 to 25 meter accuracy However adding one or two GCPs improves the accuracy to 3 to 4 meters Youcan also use the Satellite Orbital math model with the Geotiff from the Ortho Kit the text file is ignored Understanding the Rational Functions Math Model The Rational Functions Math Model is a simple math model that builds a correlation between the pixels and their ground locations Use this math model when you are missing the information needed for a rigorous math model when the sensor model is proprietary classified when the image has been geometrically processed when the data provider computed the math model and distributed it with the image or wh
170. ify how the images in your project relate to each other Since tie points are simply matching points in two or more images OrthoEngine can automate the tie point collection by using image correlation techniques To collect tie points automatically 1 On the OrthoEngine window in the Processing Step list select GCP TP Collection 2 On the OrthoEngine window click ea the Automatically collect tie points icon 3 On the Automatic Tie Point Collection window in the No of Tie Points per Area box type the number of tie points that you will use over the image or overlap area OrthoEngine User s Guide 53 Chapter 5 Collecting Control Points and Computing the Math Models 4 Inthe Matching Threshold box type a value between zero and one The Matching Threshold is the minimum correlation score that will be considered a successful match The best correlation score is one 5 Inthe Approx Elevation box type the approximate elevation of the terrain 6 Youcan also use a DEM to determine the elevation of the tie point Under Auxiliary Information click Select and select a digital elevation model DEM that covers the area The elevations of the tie points are automatically incorporated into the math model However using a DEM increases the processing time since it causes iterative computation of the model If you choose both of the above options OrthoEngine will attempt to find the elevation for each point
171. igital Elevation Models Erode Holes Since pixels adjacent to failed pixels tend to contain incorrect values as well the Erode Holes filter replaces the eight pixels around each failed pixel with the failed value When you apply the filter under a mask the mask will enlarge to cover any additional pixels replaced by the failed value Median The Median filter ranks the pixel values within a five by five pixel frame according to brightness The median is the middle value of those image pixel values which is then assigned to the pixel in the center of the frame Smooth The Smooth filter is a Gaussian filter that calculates the weighted sum of all the pixels in a three by three pixel frame and assigns the value to the center pixel in the frame Failed and background pixel values are not replaced by the filter and are not used in the Gaussian calculation Interpolate The Interpolate filter replaces failed values with an estimate weighted by distance calculated from the valid pixels surrounding the failed pixel s The algorithm used to calculate the estimate is adequate for small areas of less than 200 pixels but is not recommended for larger areas Applying Tool Strategies for Common Situations in Digital Elevation Models Editing digital elevation models DEMs requires an understanding of the desired results combined with insightful artistry to achieve the desired results Every DEM presents a variety of problematic situatio
172. igorous math model 55 computation of a simple math model 56 Compute from GCPs 11 Compute from GCPs and tie points 10 Compute from Length 23 24 Compute From Table 22 24 Connect to Tablet 46 49 Contact Information 4 contours 65 Contrast 122 convert DEM datum 126 copy chips Chip Manager 139 correcting images See Orthorectification or Geometric Correction correcting the DEM 75 76 77 78 correlation between chip and image 44 correlation between stereo image pairs 69 correlation during DEM extraction 73 correlation score 45 54 72 73 Correlation Threshold 45 CR 60 create a chip database 139 Create a mask 75 create a new chip database 135 Create Database Chip Manager 139 create epipolar images 69 Create Score Channel 72 Creating Chips from a GCP Segment 138 Cubic Convolution 105 cursor place in viewer 123 Cursor Control 123 curvature of the earth 23 24 Cutlines collecting 114 115 understanding 117 D Data Bits 46 49 61 Data Snooping 59 data strip 26 remove 31 DATA data bits 61 Database channels 123 datum 12 14 Decentering Distortion 22 24 Default Mosaic output format 128 Orthorectification output format 128 Default Parameter Settings 140 Default ROI to Image 43 Defaults change GCP color 131 change tie point color 131 for GCP elevation datum 128 for GCP elevation units 127 set channel type 129 Define Clip Region 31 during DEM extraction 72 for extracting lines from DEM 96 for geocoding DEM 80 Define Out
173. image is processed Under Corrected Image in the File box you can type a new filename for the corrected image or click Browse to select the file The default filename is o followed by the raw image s filename If you replace the default filename with the filename of an existing file with matching georeferencing and resolution the newly corrected image will replace the old If the georeferencing and resolution of the existing file do not match the newly corrected image you will have to type a new filename The Upper Left and Lower Right values may be default values or the extents from an existing orthorectified image You can click Recompute Ortho Bound to reset Upper Left and Lower Right to the default values In Working Cache type the maximum amount of RAM that you allocate for this process The limit should not involve more than half OrthoEngine User s Guide 101 Chapter 8 Correcting Your Images the RAM Specifying more than half may significantly reduce performance 11 In Sampling Interval type the interval between the pixels used to process the image For more information see Understanding Sampling Interval on page 102 12 In the Resampling list click the processing method of your choice For more information see Understanding the Resampling Options on page 104 13 Depending on the Resampling option that you chose one of the following may become available These options are explained f
174. images may no longer be in the same location Use Rename Image Photo to define the path Renaming Images on page 124 Replacing Image Pixel Values To replace the pixel values in an image you must know your images very well and understand the consequences of performing this function You are affecting the image directly not just the values held in memory OrthoEngine will identify all the instances of the selected values in the image and replace them with the new values However you may find this function useful in some situations For example if you are creating a mosaic with images containing different background values you can replace the background values of each image so that they are all the same Once the background value of all the images is the same you can create the mosaic without difficulty see Mosaicking Images with a Background Value Other Than Zero on page 113 To replace values 1 In the main menu click Utilities 2 Click Replace Image Photos Values 3 In Image File type the path for the image or click Browse to select the file 4 Click Channel and select channels from the list or click All Channels 5 In Replace Option click to replace all values less than the value set in Value to Replace to replace all values less than or equal to the value set in Value to Replace to replace all values equal to the value set in Value to Replace e to replace all values greater than
175. in the DEM If no elevation value is available in the DEM the value that you typed in the Approx Elevation box is used instead 7 Under Photos to Process or Images to Process click All Photos or All Images to collect tie points for all the images in the project or click Working Photo Working Images to collect tie points for the photograph or image designated as Working 8 Under Tie Point Distribution Pattern click Uniformly over area of each Photo or Image to distribute the tie points evenly over the entire image and match each tie point in all the overlapping images This is normally used to generate standard tie point distributions for aerial photographs such as the three by three pattern Per Overlapping Area to distribute the points evenly only in the overlap area between any pair of overlapping images This is normally used for satellite images or for aerial photographs with less than 6096 overlap 9 Under Processing Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours 10 Click Start Auto Tie Point Matching 11 Click Close fex step in your project For the next step in your project see Performing the Bundle Adjustment for Rigorous Math Models on page 55 Displaying the Overall Layout The Overall Layout feature is a quality control tool that reveals the relative positioning of the image footprints and displays a plot of
176. ine reads the raw satellite data saves the imagery into a PCIDSK file and adds a binary segment containing the ephemeris data orbit information to the file If your satellite images do not contain ephemeris data see Importing Images or Photographs into Your Project on page 15 To read images from a CD or a digital distribution format 1 On the OrthoEngine window in the Processing Step list select Data Input Click ES the Read CD ROM icon 15 Chapter 3 Importing and Viewing Images 3 Under Data Source in the CD Format box select the sensor and distribution format combination that corresponds to your data 4 Ifthe image channels are separated into several files select or type the name of the first file Depending on the format Click Select to select the file Inthe CD Image Filename box select an image Inthe CD Header Filename box select the header file If the CD Format is NLAPS LANDSAT then you should specify the name of the CD header filename instead of the CD image filename 5 Click the Requested Channels buttons corresponding to the channels that you want import Select at least one channel For each PCIDSK file that you create all the selected channels must have matching spatial resolution For satellite images with multiple resolutions import each resolution into a separate PCIDSK file 6 Ifthe CD Format is CEOS RADAR then you must select the SAR Type Select ERS or RADARSAT 7 Unde
177. ing the computation of the math model The units are the same as the input file In the Text File box type the path or click Browse to select the text file that contains the orientation parameters Under Projection type the projection string for the source data for example UTM 17 T D000 in the text box beside the Earth Model button or click Set Input Projection based on Output Projection if your input projection is the same as your output projection If you do not know the projection string Selecta projection type from the Input Projection list For UTM State Plane Coordinate Systems SPCS or Other projection types additional windows may open automatically for you to select the parameters to define the projection or click 28 PCI Geomatics Entering the Exterior Orientation Manually More to open these windows Select the parameters and click Accept Click Earth Model Click either the Datum or Ellipsoid tab Click a datum or an ellipsoid Click Accept The table under Extracted Data shows the contents of the exterior orientation extracted from the source text file If you need to rotate the Kappa value select the photographs under Extracted Data or select Rotate all photos to rotate all the photographs under Extracted Data In Rotate Kappa click a rotation button to rotate the photograph s as required Rotate Kappa only appears on the Import Exterior Orientation Data from Text File window Clic
178. ing used by the tablet to communicate how the coordinates are transmitted In Switch stream Mode coordinates are transmitted continuously as you drag the puck press the button and move the puck 12 Click Connect to Tablet Connect to Tablet should appear in the Tablet Monitor window if the tablet is communicating with the computer If you click the puck a string appears in the Tablet Monitor The position where you clicked is reported as an ASCII string The exact format of this string varies between tablets If the Format String is set correctly OrthoEngine will translate the string and point read will follow the string 13 In the Format String type the format of the command string used by the tablet to communicate the coordinates For more information see Defining the Tablet Format Strings on page 60 14 When the tablet is communicating satisfactorily click Configuration Complete Importing Ground Control Points from a File If you have several raw images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The GCP Collection window collects and displays the GCPs from the image in the Working viewer only Click Reference to switch the viewer to Working You can collect the same GCP in each image by clicking Reference in a viewer collecting the GCP and then repeating the process for each image To import ground control points from a file 1 On the Ortho
179. ints for the interpolation of the source elevations In particular a valley vector indicates a local minimum a ridge vector indicates a local maximum and a cliff vector indicates a discontinuity in the DEM In the Elevation Source list click where the elevation value is stored The elevation values can be stored in several ways such as the z coordinate of the feature or in an attribute field 66 PCI Geomatics Generating the Digital Elevation Model from Rasters Vectors or Control Points 8 Click Accept Ro step in your project See Generating the Digital Elevation Model from Rasters Vectors or Control Points on page 67 Generating the Digital Elevation Model from Rasters Vectors or Control Points Import the source for generating the DEM with one of the following Using Rasters to Generate a Digital Elevation Model on page 64 Using Ground Control Points Tie Points and or Elevation Match Points to Generate a Digital Elevation Model on page 64 Using Vectors to Generate a Digital Elevation Model on page 65 After importing the source for generating the digital elevation model DEM you determine the parameters of the DEM output To determine the output parameters 1 On the Define Output DEM file window in the Output DEM box type the path where you want to save the DEM or click Select to determine the path Click one of the following Mosaic Area to generate a DEM that
180. ion Methods for Vectors When you generate a digital elevation model DEM from vector you must determine how the values between the vectors and the raster are calculated Natural Neighbor Interpolation This method is only available when you are generating a DEM from points The Natural Neighbours algorithm constructs circles using three points based on the Delaunay triangle OrthoEngine calculates the pixel values by using all the points to form the least number of the largest possible circles Inside each circle the interpolated values are influenced by the three points forming the Delaunay triangle and all the circles that overlap that circle Natural Neighbor Interpolation is recommended for files that contain sparsely distributed or unevenly distributed points since it performs a more intelligent calculation than Finite Difference However it is not recommended for files that contain a large number of points since the calculations required will take considerable more time to process Since it does not extrapolate beyond the bounds of the points it may also leave areas of the interpolated DEM empty Finite Difference This method performs the interpolation in three steps In the first step the vector elevation values are encoded into the corresponding pixels in the raster DEM In the second step the elevations for the remaining pixels are interpolated using the Distance Transform algorithm which estimates the values from pixels eq
181. ion of the GCPs being imported from the file To change the projection type the projection string for example UTM 17 T D000 in the text box beside the Earth Model button If you do not know the projection string Select a projection type the Coordinate System list For UTM State Plane Coordinate Systems SPCS or Other projection types additional windows may open automatically for you to select the parameters to define the projection or click More to open these windows Select the parameters and click Accept Click Earth Model Click either the Datum or Ellipsoid tab Click a datum or an ellipsoid Click Accept 8 Click Accept If you did not import both the image coordinates and the ground coordinates the GCP Text File window opens Continue with the following steps If you did import the image and ground coordinates the GCPs are automatically added to the project and you can disregard the following steps 9 Onthe OrthoEngine window click ER the Collect GCPs Manually icon 10 On the GCP Text File window click a GCP from the list and click Transfer to GCP collection panel The GCP coordinates are transferred to the GCP Collection window 11 On the GCP Collection window in the boxes beside the Elev box the Easting box and the Northing box type the estimated error for each Georeferenced Position UTM 17 U E008 Elevation gt Eev s 2000 m Easting gt o5 E No
182. ist select GCP Collection al 2 Click put the Open new or existing photo icon to open an image OrthoEngine User s Guide 37 Chapter 5 Collecting Control Points and Computing the Math Models For information how to open an image see Opening Images on page 17 10 Ata zoom level where you can see the detail in the geocoded image position the cursor precisely on the feature that you will use as a ground control point GCP and click Use Point 2s E the pe Window chek Ld ene The geocoded Easting and Northing coordinates transfer to the GCP ia icon Collection window 4 On the GCP Collection window the Point ID is generated automatically You can type a new label in the Point ID box however 11 On the GCP Collection window under Georeferenced Position in all points ground control points check points tie points and elevation the Elev box type the elevation ofthe GCP or you can usea digital match points in the image must have unique labels elevation model DEM to determine the elevation of your GCPs see Using a Digital Elevation Model to Set Ground Control Point 5 Inthe list below the Point ID box click Elevation on page 51 Ground Control Point GCP to use the GCP to calculate the 12 In the boxes beside the Elev box the Easting box and the i oo Northing box type the estimated error for each Check Point CP to check the accuracy of the math model For OA more information
183. istortion box and click Accept Repeat this step with each set of distortion pairs Once you have completed the table click Accept at the bottom of the window quote We recommend that you obtain the Radial Distortion values for digital cameras Since the manufacturing of digital cameras and their lenses is often not as precise as that for high end photogrammetric cameras the Radial Distortion tends to be higher Defining Decentering Distortion Decentering Distortion is the non symmetric distortion due to the misalignment of the lens elements when the camera is assembled The Decentering Distortion values may be provided to you as P1 to P4 coefficients or in tabular format The equation for decentering distortion is delta x 1 p3r Part 2e Py r42x2 2P2Xy delta y 1 p3r Part C2Pyxy P gt r 2y where x the x image coordinate of a given image point y the y image coordinate of a given image point P the decentering distortion coefficients delta x the distortion of an image point at x and y in the x axis delta y the distortion of an image point at x and y in the y axis The decentering distortion parameter is optional and the coefficients may or may not appear in the camera calibration report To enter the distortion see Entering the Camera Calibration Data on page 24 22 PCI Geomatics Understanding Camera Calibration Data quote We recommend that you obtain the Decentering
184. ject because it provides an approximate location for the images The exterior orientation is the position and orientation of the camera when the image was taken In other words it is the relationship between the ground and the image Many photogrammetric cameras are equipped with onboard Global Positioning Systems GPS and 26 PCI Geomatics Understanding Exterior Orientation sometimes with Inertial Navigation Systems INS or Inertial Measurement Unit IMU as well These systems collect the exterior orientation directly on the plane o s Tip For more information about GPS INS see Integrated Sensor Orientation Test Report and Workshop Proceedings at http www ipi uni hannover de html publikationen special oeepe publ no43 htm The position of the camera means the x y and z location of the camera s focal point measured in a right handed mapping coordinate system The orientation of the camera is given by omega the rotation about the x axis phi the rotation about the y axis and kappa the rotation about the z axis as shown in Figure 4 2 The x y and z coordinates and the omega phi and kappa angles are referred to collectively as the six parameters of exterior orientation You can import the GPS INS data navigation solution as direct observations ofthe exterior orientation GPS INS data from any sensor system including POS EO from Applanix that uses omega phi and kappa is compatible with OrthoEngin
185. ject with a large volume of images we recommend that you enter the fiducial marks and ground control points for a limited number of images up to five complete the bundle adjustment for the math model and then check for errors before continuing It is easier to locate bad points on a few images than over the entire project To manually collect ground control points from a chip database 1 On the OrthoEngine window in the Processing Step list select GCP Collection al 2 Click the Open new or existing photo icon to open an image For information how to open an image see Opening Images on page 17 3 On the OrthoEngine window click gs the Collect GCPs from Chip Database icon EI 4 Onthe GCP Collection window the Point ID is generated automatically You can type a new label in the Point ID box however all points ground control points check points tie points and elevation match points in the image must have unique labels 5 Inthe list below the Point ID box click Ground Control Point GCP to use the GCP to calculate the math model Check Point CP to check the accuracy of the math model For more information see Troubleshooting the Math Model Solution on page 56 10 You can select Auto Locate and or Bundle Update to aid with collection For more information see Using Auto Locate on page 35 and Using Bundle Update on page 36 On the GCP Collection window under Auxiliary Information y
186. k Apply Entering the Exterior Orientation Manually For more information about exterior orientation see Understanding Exterior Orientation on page 26 To enter the Exterior Orientation manually l On the OrthoEngine window in the Processing Step list select Data Input Click SS the Enter GPS INS or exterior orientation data manually icon If you chose Compute from GCPs and Tie Points when you started your project the Input GPS INS Data Manually window opens If you chose User Input when you started your project the Input Exterior Orientation Data Manually window opens Under Projection type the projection string for the source data for example UTM 17 T D000 in the text box beside the Earth Model button or click Set Input Projection based on Output Projection if your input projection is the same as your output projection If you do not know the projection string Selecta projection type from the Input Projection list For UTM State Plane Coordinate Systems SPCS or Other projection types additional windows may open automatically for you to select the parameters to define the projection or click More to open these windows Select the parameters and click Accept Click Earth Model Click either the Datum or Ellipsoid tab Click a datum or an ellipsoid Click Accept Under Unit click the unit for the orientation angles Under Photos select a photograph The exterior orientation parameters
187. l ID and Scene ID boxes should be filled automatically with the information you provided when you opened the source image 10 If you have a DEM click Extract Elevation to extract the elevation value for the GCP If you do not have a DEM the elevation value may appear in the GCP list on the GCP Segment File window 11 In the boxes beside the Elev box the Easting box and the Northing box type the estimated error for each Elevation 3 Elev 2 000 m Easting Gos E Northing gt fas n 12 In the list beside box for the Elev box select Meter or Feet 13 Click Save chip Changing the Location of the GCP You can change the location of the ground control point GCP on an existing chip 138 PCI Geomatics Searching the Chip Database To change the location of the GCP on the chip 1 Onthe PCI ImageChipsManager window click on the new location for the GCP 2 Click Accept GCP from cursor 3 Click Save chip To undo the change click Cancel Searching the Chip Database To search the chip database 1 On the PCI ImageChipsManager window do one of the following Click the button type the chip ID or chip sequence number and then click OK Use the navigation buttons to select the chip Inthe main menu click Utilities and click Search image chips to narrow the search for chips to a manageable number For information about searching the chip database see Searching f
188. l selection for the remaining images You can delete the uncorrected image from the disk when the process is complete Select an image under Photos to Process and select Delete input file when done Repeat for each image that you want to delete after the image is processed Under Ortho Photo in the File box you can type a new filename for the orthorectified image or click Browse to select the file The default filename is o_ followed by the raw image s filename If you replace the default filename with the filename of an existing file with matching georeferencing and resolution the new orthorectified image will replace the old If the georeferencing and resolution of the existing file do not match the new orthorectified image you will have to type a new filename The Upper Left and Lower Right values may be default values or the extents from an existing orthorectified image You can click Recompute Ortho Bound to reset Upper Left and Lower Right to the default values which represent the computed footprint ofthe image on the ground If the computed bounds appear too large or too small it may indicate errors in the math model or the DEM Under DEM click Browse to select the DEM On the Database File Selection window select the file and click Open Select the database channel containing the elevation In the Background Elevation box type the value representing the No Data pixels in the DEM and click Select If you do
189. l the size of the frame with the Filter Size option by typing the number of pixels width in the X box and the number of lines length in the Y box Different filter sizes greatly affect the quality of the processed images If the filter is too small the noise filtering algorithm is not effective If the filter is too large subtle details of the image are lost in the filtering process The minimum size for the frame is 3 by 3 pixels A 7 by 7 frame usually gives the best results Image Format The radar images are supplied in one of two Image Formats Power or Amplitude Power is the sum of the squares of the real and imaginary values ofthe complex pixel values in the radar image Amplitude is the square root of Power Most radar images are supplied in the Amplitude format to preserve the values You identify the format used with your images in the Image Format list Number of Looks You use the Number of Looks to estimate noise variance and to control the amount of smoothing applied to the image In theory the correct value for the Number of Looks should be the effective number of looks ofthe radar image or close to the actual number but it may be different if the image was resampled Using a smaller value for the Number of Looks leads to more smoothing and a larger value preserves more OrthoEngine User s Guide 107 Chapter 8 Correcting Your Images image features In the No of Looks list select the Number of Looks tha
190. l to select all the available channels Click Add Epipolar Pairs To Table to record the pair s under List of Epipolar Pairs If you selected User Select repeat steps 3 and 4 until you have recorded all the pairs that you want Under List of Epipolar Pairs the pairs with a check mark in the Select column will be converted into epipolar pairs You can modify your choices by using the following To select or remove a pair from the list under the Select column click to select or clear the check mark of the pair of your choice To select all the pairs in the list click Select All To clear all the check marks click Select None To eliminate one pair from the list under the Number column click the pair of your choice and click Remove To eliminate all the pairs from the list click Remove All Tointerchange the left and right images in a pair under the Number column click the pair of your choice and click Switch Pairs To interchange the left and right images in all the pairs click Switch All Pairs If you chose Maximum Overlapping Pairs or All Overlapping Pairs the left and right images in the pair may be in the wrong order meaning that the left image is on the right and vice versa This situation will not affect DEM generation but it will cause some visually disturbing effects if you try to view the epipolar pair in three dimensions 3 D Our brains are trained to interpret the images seen from our left and right eyes in a
191. lation The Nearest Neighbor Interpolation resampling option identifies the gray level of the pixel closest to the specified input coordinates and assigns that value to the output coordinates Although this method is considered the most efficient in terms of computation time it introduces small errors in the output image The output image may be offset spatially by up to half a pixel which may cause the image to have a jagged appearance Bilinear Bilinear Interpolation The Bilinear Interpolation resampling option determines the gray level from the weighted average of the four closest pixels to the specified input coordinates and assigns that value to the output coordinates This method generates an image with a smoother appearance than Nearest Neighbor Interpolation but the gray level values are altered in the process which results in blurring or loss of image resolution Cubic Cubic Convolution The Cubic Convolution resampling option determines the gray level from the weighted average of the 16 closest pixels to the specified input coordinates and assigns that value to the output coordinates The resulting image is slightly sharper than one produced by Bilinear Interpolation and it does not have the disjointed appearance produced by Nearest Neighbor Interpolation Sin 8 Pt and 16 Pt SinX X The 8 Pt SinX X resampling option determines the gray level from the weighted average of the 64 closest pixels to the specified input c
192. level 1 CDs Level 0 is raw and level 1 is radiometrically corrected Other levels are not recommended JERS1 LGSOWG JERS 1 CD provides different levels of processing We recommend that you use a georeferenced level or equivalent for highest accuracy OrthoEngine only works for descending order images LANDSAT 5 Brazilian Full scene with level 4 or 5 processing level LANDSAT 5 EOSAT LANDSAT 5 image full scene data ORBIT ORIENTED or MAP ORIENTED product ORBIT ORIENTED is recommended SYSTEMATIC geodetic processing 18 PCI Geomatics Supported Satellite Formats LANDSAT 5 7 LSGOWG Canadian CDs LANDSAT full scene or sub scene image data Level 4 processing bulk radiometric and along scan line geometric corrections applied Level 5 processing georeferenced CD e You should use level 4 CD with supplemental volume for highest accuracy LANDSAT 5 7 LSGOWG ESA CDs Level 5 full scene or quad scene LANDSAT 5 NLAPS NLAPS full scene with level 8 processing level LANDSAT 7 HDF TIFF FAST NLAPS Full scene with 1G progressing in HDF Tiff Fast or NLAPS format OR or IR is not recommended because of discontinuity on the image The header file for HDF is the file that contains HDF or hdf The header file for Tiff is the file that contains TIF or tif The header file for Fast is the file that contains HPN hpn HRF hrf HTM or htm The header file
193. line coordinates from the feature in each image appear in the Elevation Match Point Collection window under Photo Positions 7 Inthe Elevation Match Point Collection window click Accept The point and its elevation appear under Accepted Elevation Match Points Collect as many points as needed to satisfactorily express the terrain 8 To edit a point click the point under Accepted Elevation Match Points Under Photo Positions click Quick Open beside the image that you want to edit Reposition the cursor precisely on the feature click Use Point and then click Accept To remove a point click the point under Accepted Elevation Match Points and click Delete 9 Click Create DEM to generate a DEM from the points When Include GCP Tie Points to Build DEM appears click Yes if you want to use the project s ground control points and tie points to generate the DEM Add to DEM to add the points to an existing DEM This is useful if you want to add more points to an area where you are not satisfied with the results Save Pts to File to save the points to an ASCII file Type the path for the file that you want to add the points to or click Browse to select a file Click Create If the text file exists you can click Append to add the points to the end ofthe file or click Delete to remove the file and create a new one 10 Click Close fes step in your project See Generating the Digital Elevation Model from Rasters Vecto
194. litude 108 PCI Geomatics Understanding the Resampling Options format to preserve the values You identify the format used with your images in the Image Format list Number of Looks You use the Number of Looks to estimate noise variance and to control the amount of smoothing applied to the image In theory the correct value for the Number of Looks should be the effective number of looks ofthe radar image or close to the actual number but it may be different if the image was resampled Using a smaller value for the Number of Looks leads to more smoothing and a larger value preserves more image features In the No of Looks list select the Number of Looks that you want to apply to the image Radar Kuan Filter The Radar Kuan resampling option determines the gray level for each pixel by replacing the center pixel with a weighted average of the central pixel and the mean of the values in a square frame surrounding the pixel To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data This filter is used primarily to suppress speckle It smooths image data without removing edges or sharp features in the images while minimizing the loss of radiometric and textural information The Kuan filter first transforms the multiplicative noise model into a signal dependent additive noise model Then the minimum mean square error criterion is applied to the model The resulting gray l
195. ll move to that exact location in the viewer Change the projections under Geocoded or User Defined Projection to view the cursor location in different projections Changing Image Color Channels You can select which image channels as a red green or blue color using the RGB Image Mapper To change the colors of an image layer 1 Click the Open new or existing photo icon to open an image For information how to open an image see Opening Images on page 17 2 Click the 111 Open RGB Mapper icon The RGB Mapping window opens displaying a list of all the available image channels for the image 3 Click under Red Green or Blue to select the color for the image channels that you want to change 4 Click Close Selecting Image Channels If the image that you are opening contains several channels you will have the choice of which ones you want to display in your project When the Database Channels window opens click up to three channels to be displayed in the viewer You can change which image channels are mapped to which channel in the viewer using the RGB Mapper see Changing Image Color Channels on page 123 OrthoEngine User s Guide 123 Chapter 10 Additional Features The Average Image feature controls how the image pixels are displayed in the viewer One screen pixel can represent many image pixels Normally OrthoEngine simply chooses an image pixel value to represent the group being mapped t
196. llite images with multiple resolutions import each resolution into a separate PCIDSK file 6 Ifthe Tape Format is CEOS RADAR then you must select the SAR Type Select ERS or RADARSAT 7 Under Data Output in the PCIDSK Filename box type the name of the output file 8 Inthe Scene Description box type a description of the file optional 9 Inthe Report Filename box type the name ofthe file where the report will be saved 10 Click Read 16 PCI Geomatics Reading Satellite Data from a Generic Image File Ho step in your project See Collecting Control Points and Computing the Math Models on page 33 Reading Satellite Data from a Generic Image File You can create an orbital model for image formats that do not have embedded orbital ephemeris data by manually entering information about the satellite image and orbit data To read satellite data from a generic image file 1 On the OrthoEngine window in the Processing Step list select Data Input 2 Click u the Read Generic Image File icon 3 Inthe Read Generic Image File window in the Input File box type the filename ofthe generic image file or click Browse to select the file The input file can be in any supported format 4 Inthe Output File box type the filename where you want to save the project or click Browse to select a folder The output file will be saved in the PCIDSK format 5 Under Satellite Information enter information about the
197. lowest probability of error that is not noise This feature is available after the bundle adjustment is performed 7 Editthe points as required For more information see Editing Points in the Residual Report on page 59 8 Click Print to File to save the report in a text file In Report File type the path for the text file or click Select to choose a location Click Append to the report to an existing file or click Overwrite to replace or create a file Perform Bundle Adjustment to compute the solution for the rigorous math model For more information see Understanding the Bundle Adjustment for Rigorous Math Models on page 55 Re step in your project See Editing Points in the Residual Report on page 59 Editing Points in the Residual Report The Residual Report contains the residual errors for the points in your project Residual errors are the difference between the coordinates that you entered for the ground control points GCPs or tie points and where the points are according to the computed math model To understand how to evaluate the points in your project see Troubleshooting the Math Model Solution on page 56 To edit the points in your project 1 In the table on the Residual Errors window click the image that contains the point that you want to edit Click Edit Point 2 The viewer and GCP Collection or Tie Point Collection window open for the selected point In the viewer click to indicate
198. luate the accuracy of your model see Troubleshooting the Math Model Solution on page 56 Ro step in your project For Polynomial projects see Geometrically Correcting Your Images on page 101 Thin Plate Spline The Thin Plate Spline math model solution will use the GCPs simultaneously to fit the raw image to the ground coordinate system by distributing the transformation over the entire image To evaluate the accuracy of your model see Troubleshooting the Math Model Solution on page 56 Ho step in your project For Thin Plate Spline projects see Generating Digital Elevation Models on page 63 or Correcting Your Images on page 97 Troubleshooting the Math Model Solution Since determining the best possible solution for the math model is the foundation of your project it is important for you to know if your solution is good enough to achieve the results you expect If it is not you must also know what to do to adjust the model The Residual Errors will help you determine if the solution is good enough for your project Residual errors are the difference between the coordinates that you entered for the ground control points GCPs or tie points and where those points are according to the computed math model You can see the residual errors for the image on the GCP Collection windows in the Residual column or you can generate a Residual Report for the entire project see Generating a Residual Report on
199. mage icon 3 In the list under Epipolar Selection choose one of the following options Click User Select to select the pairs manually Under Left Image and Right Image click the images that you want to form the pair For ASTER images use the nadir image as your left image For OrthoEngine User s Guide 69 Chapter 6 Generating Digital Elevation Models RADARSAT images use the image with the larger incidence angle as your left image Maximum Overlapping Pairs to automatically select the pairs that demonstrate the highest amount of overlap Each image forms pairs with the two images that overlap it the most In the Minimum Percentage Overlap box type or select the lowest percent of overlap acceptable between two images to be considered a valid pair All Overlapping Pairs to automatically select all the pairs that overlap above the specified minimum percentage In the Minimum Percentage Overlap box type or select the lowest percent of overlap acceptable between two images to be considered a valid pair Figure 6 3 Comparing All Overlapping Pairs and Maximum Overlapping Pairs If All If Maximum Overlapping Overlapping Pairs is selected Pairs is selected the pairs that the pairs that contain image B contain image B will be will be A and B A and B C and B C and B D and B E and B F and B D 4 Under Left Image and Right Image click Channels and type the channel s that you want to use or click Al
200. mage with three bands selected automatically If the image was not opened previously it will open with the first three bands selected automatically If the image was opened previously by clicking Open it will open using the bands that you selected the last time you opened the image Quick Open amp Close to open the image as if you clicked Quick Open and then have the Open Photo window close automatically fex step in your project See Collecting Control Points and Computing the Math Models on page 33 Supported Satellite Formats The following is a list of supported input formats for OrthoEngine ASAR ASAR IB format ASTER ASTER Level 1A and 1B HDF format However we recommend Level 1A to obtain the highest accuracy Level 1B is not recommended IKONOS The IKONOS provides different levels of processing The following formats are recommended GEO product in UTM WGS84 GeoTiff format NITF format with or without rational function For color data stored in separate files you can point to any Tiff file Channel 1 2 3 and 4 correspond to red green grn blue blu and near infrared nir data IRS EOSAT IRS full scene data ORBIT ORIENTED or MAP ORIENTED product Quote This format is not recommended You should use Super structure format for highest accuracy IRS Super Structure The IRS Super Structure CD provides different levels of processing OrthoEngine supports level 0 and
201. mation see Defining the Tablet Format Strings on page 60 To add or modify a tablet In step 6 of Setting Up the Tablet on page 46 1 In the Tablet type list click Create to add a new tablet or click Edit to modify the settings of an existing tablet Two windows open Tablet Monitor and Tablet Configuration 48 PCI Geomatics Importing Ground Control Points from a File 2 On the Tablet Configuration window in the Tablet Name box type the name of the tablet that you are adding 3 In the Device Name type the communication port that you are using 4 Inthe Baud Rate list click the baud rate used by the tablet 5 In the Parity list click the parity bit setting used by the tablet 6 In the Data Bits list click the data bits used by the tablet 7 Inthe Stop Bits list click the stop bit used by the tablet 8 In the Initialization box type the command string that the tablet sends to the computer to initiate communication 9 Inthe Point Mode box type the command string used by the tablet to communicate how the coordinates are transmitted In Point Mode a coordinate is transmitted each time you click a button on the puck 10 In the Stream Mode box type the command string used by the tablet to communicate how the coordinates are transmitted In Stream Mode coordinates are transmitted continuously as you move the puck whether you click a button or not 11 In the Switch stream Mode box type the command str
202. n see Opening Images on page 17 The Fiducial Mark Collection window opens automatically 3 Click the approximate location of a fiducial mark in the opened image 4 Click the Zoom In button until you can see the fiducial mark clearly Click precisely in the center of the fiducial mark EE In the Fiducial Mark Collection window click Set beside the fiducial mark location corresponding to the mark that you clicked in the opened image Ignore the orientation of the scanned image Follow the locations of the fiducial marks as they appear in the image on the screen For example if you clicked in the upper left corner of the image on your screen to collect the fiducial mark then you click Set beside Top Left in the Fiducial Mark Collection window OrthoEngine automatically adjusts its parameters to account for the orientation of the scanned image relative to the orientation of the camera Click the Zoom Out button to reduce the magnification and repeat the process to collect the remaining fiducial marks Under Errors OrthoEngine compares the computed fiducial mark positions based on the measurements taken from the screen with the fiducial information that you entered from the camera calibration report Click Clear beside any fiducial marks where the error is not acceptable and repeat the collection process The error should be less than one pixel unless the image is scanned at a very high resolution Large errors may indica
203. n the Elev box type the elevation of the GCP or you can use a digital elevation model DEM to determine the elevation of your GCPs see Using a Digital Elevation Model to Set Ground Control Point Elevation on page 51 13 In the boxes beside the Elev box the Easting box and the Northing box type the estimated error for each Georeferenced Position UTM 17 U E008 Elevation gt Elev 2 2000 m Easting 0 5 E Northing gt J0 5 N Longitude eng Lat Latitude Accept Delete New Point 14 At a zoom level where you can see the detail in the raw image position the cursor precisely on the feature that you will use as a GCP and click Use Point The pixel and line coordinates from the raw image appear in the GCP Collection window under Photo Position or Image Position 15 Click Accept The GCP is added to the Accepted Points table Tip You can edit the error estimate in the boxes under Image Position to correspond to your ability to precisely identify a feature in the image For example if you use coarse imagery you can probably only measure to the closest pixel If you use imagery that was compressed or poorly scanned you may only be able to measure to the closest two pixels Even if you identify a GCP to the closest pixel the coordinate may only be accurate to so many meters Ros step in your project For projects using the Aerial Photography or Satellite Orbi
204. n click Use Point You can open all the images that have the same feature in common and collect the tie point for them all by selecting the feature in each image and clicking Use Point in each image The Tie Point Collection window displays the tie points collected for the image designated as Working You can also enter the tie point s elevation optional by Onthe Tie Point Collection window select the Elevation check box type the elevation in the Elevation box and type the estimated error in the box Click Select and select a digital elevation model DEM that covers the area The elevation of the tie point is automatically incorporated into the math model If you choose both of the above options OrthoEngine will attempt to find the elevation for each point in the DEM If no elevation value is available in the DEM the value that you typed in the Elevation box is used instead 8 Under Reference Photo Tie Points click Accept 2 s Tip You can use the edges of lakes parking lots or flat fields as tie points with elevation since it is easy to estimate the elevation of these points from topographic maps or digital elevation models He step in your project For the next step in your project see Performing the Bundle Adjustment for Rigorous Math Models on page 55 Collecting Tie Points Automatically Used only in rigorous models such as Aerial Photography and Satellite Orbital math models tie points ident
205. nce frame between the tablet the paper map and your project To set up the tablet 1 On the OrthoEngine window in the Processing Step list select GCP Collection al 2 Click the Open new or existing photo icon to open an image For information how to open an image see Opening Images on page 17 3 On the OrthoEngine window click B the Collect GCPs by tablet icon 4 On the GCP Collection window click Set Up Tablet 5 In Tablet Setup and Map Tie down window in the Device box type the name of the serial port where you have attached the digitizing table For example serial ports for Windows systems are COM1 or COM2 and for Unix systems are dev ttys1 or dev ttya 6 Inthe Tablet type list click the type of tablet that you are using 7 Inthe Baud Rate list click the baud rate used by the tablet 8 Inthe Parity list click the parity bit setting used by the tablet 9 Inthe Data Bits list click the data bits used by the tablet 10 In the Stop Bits list click the stop bit used by the tablet 11 12 13 14 15 16 17 Click Connect to Tablet Press a button on the tablet s puck to verify the communication between OrthoEngine and the digitizing table Values should appear in Tablet Coordinates In Coordinate System type the projection string for example UTM 17 T D000 in the text box beside the Earth Model button If you do not know the projection string Select a projec
206. ndow and open a digital elevation model DEM that covers the area of your source image Click Extract Elevation Ifyou have your source image and its DEM in the same file click Elevation channel click the DEM channel on the Elevation Channel Selection window and click Close The elevation of the point that you selected in the source image is transferred to the window under Ground Control Point Information 9 Inthe boxes beside the Elev box the Easting box and the Northing box type the estimated error for each Elevation gt Elev 2 2 000 m Easting b5 E Norhing s w 10 In the list beside box for the Elev box select Meter or Feet 11 Click Save chip Determining the Size of the Chip The cursor at the center of the chip outline becomes the ground control point GCP when you save the chip in the database OrthoEngine User s Guide 137 Chapter 11 Creating a Chip Database To change the size of the chip footprint 1 In the viewer displaying the source image click Chip Size The default chip size is 64 by 64 pixels The maximum chip size is 256 by 256 pixels 2 Select one of the following Type the number of pixels and lines in the Size boxes Click Drag out square on image and drag a square over the area that you want on the source image Click Drag out rectangle on image and drag a rectangle over the area that you want on the source image 3 Click Close
207. ner en nenne errem nennen 40 Searching for Chips ina Database wisn 42 Working with the Chip Database cirios dia de diia 43 Collecting Ground Control Points from a Chip Database Automatically ooooooncnnnncccnnocccnnocnnnnoncnononnnc conocio nnnn conan nnnnnnn nennen nnne nnne nnne 43 Changing the Correlation Parameters for Automatic GCP Collection from a Chip Database sseee em 44 Using a Tablet to Collect Ground Control Points sssssssesseee enne nennen ener nennen ient s eterne nene entren neret nene enne enne 45 Setting Up the Tablet TER 46 Collecting Ground Control Points from a Tablet s sisien nanii a Ea A a a daa E iada aa aAA E a TEE aint 47 Adding or Editinga Tableta a 48 Importing Ground Control Points from a Filesi ae a rro rr nr 49 Using a Digital Elevation Model to Set Ground Control Point Elevation oooonnnnnccnnnnconnnnacannonccnnnannn nono nono ro ncnnn nennen mne emere nere enne nnns 51 Understanding Tie Points 8 iia ana D Ae pei o e A tac 51 Choosing Quality Tie Poilnts 1 5 eee coda Get im e A ad 52 Collecting Ti defe Ih RID ENEE 52 Collecting Tie Points A tomaticallV ociosas 53 Displaying the Overall Layout aiii 54 Understanding the Bundle Adjustment for Rigorous Math Models sese eene nnne nana nene enne en n
208. nformation about the features set for the mosaic such as its resolution and bounds Camera Calibration to include the information from the Standard Aerial Camera Calibration Information window or Digital Video Camera Calibration Information window Under Photos select the images that you want to include in the report Press SHIFT or CTRL and click to select more than one image Under Photo Information select as required General to include general information about the images that you selected such as the number of channels the image size details about the orthorectified version of the image and which digital elevation model was used Exterior orientation to include information about the x y and z location of the camera and the orientation of the camera in omega the rotation about the x axis phi the rotation about the y axis and kappa the rotation about the z axis Satellite Model to include the position and orientation of the satellite Orbital data to include information about the sensor such as the Field of View View Angle and Eccentricity Geometric Model to include information about the math model solution Under Point Information select Ground control points to include a list of the GCPs collected in the selected images Tie points to include a list ofthe tie points collected in the selected images Fiducial marks to include the positions of the fiducial marks in the selected images
209. ng double precision real numbers 92 PCI Geomatics Assigning Attribute Values Float to define the field as containing single precision real numbers Textto define the field as containing a string of text Integer List to define the field as containing a list of positive or negative whole numbers separated by commas 6 Inthe Width list type the maximum field size Although characters that exceed the field size are not cut short in the pix format other formats may discard the excess characters 7 Inthe Precision list type the number of characters that can be displayed after the decimal point The definition only controls how the value is displayed and does not round off the value you that type into the field This field is only valid when it is defined as a Double or Float Data Type 8 Inthe Justify list select Left Justify if you want to left align the characters in the field or select Right Justify to right align the characters This field is not valid when it is defined as an Integer List Data Type 9 Inthe Default box type the default characters for the field if desired If you change the default previously existing shapes using the default will not change 10 Click Accept The new column is added to the Attribute table 11 You can follow steps 3 to 10 to add another column or click Cancel 12 On the Vector Field Definition window click Close Ro step in your project See Assigning Att
210. ng the check mark will not clear the DEM options set for any of the images You will have to reset the DEM options for each image separately In Working Cache type the maximum amount of RAM that you allocate for this process The limit should not involve more than half the RAM Specifying more than half may significantly reduce performance In Sampling Interval type the interval between the pixels used to process the image Make sure that you set the interval correctly especially in rugged areas Setting it too high will reduce the detail of the terrain correction For more information see Understanding Sampling Interval on page 102 17 18 19 20 21 In the Resampling list click the processing method of your choice For more information see Understanding the Resampling Options on page 104 In Auto Clip Edge type the percentage of the image s outside edge that you want to remove You can use this option to remove unwanted areas such as the data strip and fiducial marks from aerial photographs or a dark perimeter or distortion along the edge of the image Depending on the Resampling option that you chose in step 17 one of the following may become available In Filter Size type the number of pixels in width in the X box and the number of pixels in length in the Y box to determine the size of the frame used with the filter n Gaussian SQ box type the first value In the 2 box type the second value to
211. ning Chip Size and Y Scale Factor The Chip Size is the physical size of the Charged Coupled Devices CCDs in digital or video cameras Since the images from digital and video cameras do not contain fiducial marks the size of the CCDs is used to calculate the geometry of the camera Most cameras have square sensor cells but some especially video cameras may have rectangular sensor cells The Y Scale Factor is the ratio between the horizontal and the vertical size of each sensor cell in digital or video cameras It is used when the CCD pixels are not square Using the Chip Size and Y Scale Factor the digital or video image is automatically converted into a normalized square photo coordinate system The image can then be processed during the computation of the math model the bundle adjustment in the same way as an image taken with a standard aerial camera To enter the Chip Size and Y Scale Factor see Entering the Camera Calibration Data on page 24 Entering the Camera Calibration Data The Standard Aerial Camera Calibration Information window or the Digital Video Camera Calibration Information window may open automatically after completing the Set Projection window If it is open skip to step 3 For more information about camera calibration data see Understanding Camera Calibration Data on page 21 To enter the camera calibration data 1 On the OrthoEngine window in the Processing Step list select Project 2 Click the
212. nn rre 96 Chapter 8 CORRECTING YOUR IMAGES Understanding Orthorectification bt 97 Orthorectifying Your IMAGES ias 98 Understanding Elevation Scale and Offset 2 ccteecccesneceegeccetetscadeseceneueesdeenncecsecnenpescenenaettecopeneuanereegaeesbecceasseeeceqentpectaeeuecneetageteugontnsensinesaaeees 100 Understanding Geometric Correction 2 5 ete occi ri liar ii sels eens dd d dosi donee de cave nud ds 100 Geometrically Correcting Your Images 2 0ccdeccencsacedesecsessceeeeastcenseceeecnopsdnnetreauedenssceatedacusnsddacaeequessnednsddedenoeensuederbannasscnuaeenagedpetateessesentanes 101 Understanding Sampling Interval c0oci 102 Understanding the Status Descriptions ene ette ete ea eel ete Hes 103 Troubleshooting Your Orthorectified Images iaiiaeeeai ienee i dread nennen enne sensit sent EETAS tenen entre en ner rennen enne 104 Understanding the Resampling Options ssssessseeeeee ron 104 Nearest Nearest Neighbor Interpolation sssssssssssssseseseseeen esee etnnennren eren ESEESE EEES sls sn nnne sisi nn neris sedet nan insi enne rr narran 105 Biliriear Bilinear Interpolation ota pet RH EHE I Ote tin qe pe vd rea ERR X rete trina 105 Cubic Cubic Convolution EE 105 Sin e Ptand 16 Pt SInX X ette E A T 105 Average Filter ovina lada bis 106 Median Rilter a ii uina 10
213. ns The following examples present the most common problems and provide some methods to handle them Equalizing Pixel Values for Lakes Since lakes do not have features that can be used for matching during DEM extraction lakes in the DEM often contain failed pixel values or incorrect elevation values To adjust a lake s pixel values 1 Create a mask over the lake 2 Identify the elevation of the lake 3 Type the value in the Value box beside Fill Using Value 4 Click Fill Using Value This sets the entire lake to a flat surface at the correct elevation 5 Click Clear Mask To adjust the pixel values for several lakes 1 Select Interpolate and click Apply Under Mask The elevation of the lake is interpolated using the values along the shoreline 2 Click Fill Each Polygon with Polygon Average The average elevation is calculated under each mask and applied to the area As a result each lake has a flat surface of approximately the correct elevation 3 Click Clear Mask Compensating for Forests and Urban Areas The repetitive textures of forests and urban areas often cause those areas to contain a lot of failed values noise and poorly correlated elevation values 78 PCI Geomatics Geocoding a Digital Elevation Model To compensate for forests or urban areas 1 Create a mask over the area 2 Type the failed value in the Value box beside Fill Using Value 3 Click Fill Using Value This sets
214. nt to begin the line When you are satisfied with the x and y positions adjust the z position elevation of the stereo cursor and click to anchor the vertex You can also use Snap to Vertex or Snap to Line to position the cursor For more information see Using Snap to Vertex on page 90 and Using Snap to Line on page 90 Beneath the 3 D viewer you can see the x y and z coordinates of the stereo cursor s location 4 Move the stereo cursor to the next position When you are satisfied with the x and y positions adjust the z position and click to anchor the vertex 5 Repeat step 4 until you have collected the vertices that you need to form the line 6 Click Accept or double click when you collect the last vertex to confirm the completion of the line After the new line is accepted it will change from the highlight color white to the color specified for the selected layer in the Vector Layer Information table 7 You can repeat steps 3 to 6 until you have collected the lines that you want for the selected layer 8 Click New Line to stop collecting lines 2 s Tip When you are working with the stereo cursor in the 3 D viewer you can press G to snap the stereo cursor to the ground press ENTER to confirm the completion of the line press L to activate and deactivate New Line For more shortcuts see Using Shortcuts in the 3 D Viewer on page 94 He step in your project See Designing the Attrib
215. ntes snis inn Ennan enne 6 Understanding the Polynomial Math Model ooooconnnccnnoconnoncccncncnnnonnnonannc cnn nn nor none n nera eren enne 7 Understanding the Thin Plate Spline Math Model ooooconnoccccnnoccccocccnnnoncconancnn nono no nan nc naar nemen nennen nennen rene n rre senten enne nnne 8 Starting OrthoEnglrie 3 eer tdeo elena A AAA ine 9 Starting a Project Using the Aerial Photography Math Model ssssssseeeseee enne enneennene ennrnen ner en tense en nr nennen nennen nnns 9 Starting a Project Using the Satellite Orbital Math Model sssseseeeenenenen mener nne enne enr in triente seen nennen nennen 10 Starting a Project Using the Rational Functions Math Model sse carne 11 Starting a Project Using the Polynomial Math Model ssssseseeeene cnn non ono noc tanit rre 11 Starting a Project Using the Thin Plate Spline Math Model ooococcccnnocccnnncconoooccnonanonononcnnnrnncnn tutkitut ano nee nr nnn cren rre rr 12 Starting a Project to Mosaic Existing Georeferenced IMages ooccononccnnncccnnocccnnnonccnnnnnnnononcnnn nn narrar rn rre rr 12 Understanding Projections and DAUM ea e e ceca er a r seis et nesr sitne risit eiit esit siens rens sides stent tete e essen nnn renean s 12 Setting Ihe PrOjSCtiOn cita DERI ER ERI dee EO ERU EIU i enr Ot 13 Chapter 3 IMPORTING AND VIEWING IMAGES Importing Images or Photographs into Your Project ssssssss
216. ntrol or insufficient ground control Residual Errors Are All Zero If all the residual errors for the GCPs and tie points read zero it usually indicates that you have collected only the minimum number of ground control points or fewer Collect more GCPs and tie points However if you selected the Thin Plate Spline math model for your project the residual errors will always indicate zero Use Check Points to check the accuracy for the Thin Plate Spline math model For more information on Thin Plate Spline see Understanding the Thin Plate Spline Math Model on page 8 For more information on Check Points Troubleshooting the Math Model Solution on page 56 Systematic Trends in Residual Errors If you have high residual errors in one part of an image or project it can indicate that you need more ground control in the problem area or it may indicate that you have one or more bad points in the area that are skewing the math model Some bad points are difficult to identify since some points may compensate for others Ho step in your project For the next step in your project see one of the following Generating Digital Elevation Models on page 63 Editing Features in 3 D Stereo on page 81 Correcting Your Images on page 97 Generating a Residual Report The Residual Report helps you determine if the math model solution is good enough for your project Residual errors do not necessarily reflect errors in the GCPs or tie
217. nts GCPs for each image in your project In this case you should not use tie points tie points with elevation or even stereo GCPs These points become mathematically useless due to the same side weak stereo intersection If you are co registering two scenes from a single sensor such as a panchromatic image and a multispectral image of the same scene do not use tie points to relate the images Use the same GCPs on both scenes Collecting the same GCPs on adjacent images can also improve the math model by improving the B H ratio When the viewing angle difference between the images is between 7 and 30 degrees meaning a B H ratio between 0 1 to 0 15 and 0 6 you can use tie points with elevation to reduce the minimum required GCPs for each image When the viewing angle difference between the images is more than 30 degrees meaning a B H ratio more than 0 6 you can use tie points to extend the ground control If you use tie points with elevation you can reduce the minimum required GCPs for each image For example if you have stereo left and right SPOT images you can collect two GCPs on the left image and two GCPs on the right image With tie points with or without elevation in the overlap you can obtain a geometric model Using Auto Locate The Auto Locate feature appears on the GCP Collection windows the Tie Point Collection window and the Elevation Match Point window It is a tool to help you speed up the collection process
218. o match dark values a match area in urban areas to match urban areas and so on Using a single large match area covering a large part ofthe image is effective only if you have an overall bright or dark difference between the images OrthoEngine User s Guide 117 Chapter 9 Mosaicking Your Images Changing the Layout in the Manual Mosaicking Window Select one of the following methods in the Layout list to determine how you want to display the images in the viewer Interleave to display alternating lines from the images already mosaicked and the image that you are adding to the mosaic This method is particularly effective when you want to view full color images Sharp unstriped areas indicate where the features match well and the radiometry is similar The Layout list can contain Mosaic Interleave for grayscale images or Interleave Color Interleave Red Interleave Green and Interleave Blue so you can select the channels for colored images Overlay to display the images already mosaicked in red and the image that you are adding to the mosaic in cyan Sharp grayscale areas indicate where the features match well and the radiometry is similar The Layout list can contain Mosaic Overlay for grayscale images or Overlay Red Overlay Green and Overlay Blue so you can select the channels for colored images Double Window to display the images already mosaicked in the viewer and the image that you are adding to the mosaic in a sep
219. o the range of higher values brightness in the histogram so finer details become brighter Hold freezes the current appearance of the image which improves the loading speed of the image Tail Trim to omit the upper and lower 2 percent of the image histogram to remove outliers in the upper and lower part of the pixel range Tail Trim uses a 2 percent margin by default but you can adjust the amount of tail trim from 1 to 5 percent with Set Trim Exclude Min Max disregards the lowest and the highest value in the image histogram before applying the Tail Trim Set Trim to adjust the amount of tail trim from 1 to 5 percent Re enhance The enhancement is recalculated each time the zoom level is changed by building a histogram with the range of values available in viewer unless the viewer contains the Re enhance button Click the Re 121 Chapter 10 Additional Features enhance button to recalculate the histogram using the range of values existing in the viewer at the time that you applied the enhancement Brightness Ol Brightness controls the overall luminosity amount of light in the images Click the arrow beside the Brightness icon to increase or decrease overall luminosity Contrast 9 Contrast controls the difference between the light and dark extremes in the images Click the arrow beside the Contrast icon to increase or decrease the light and dark extremes Using Zoom ReLoad and Pan Zoom Several w
220. o the screen pixel Average Image calculates the average value of that group of image pixels and uses that value for the screen pixel This process is also known as block averaging This process often produces more meaningful representation of the image in the viewer Removing Images When you remove an image from the project the ground control points tie points fiducial marks and so on are removed as well However you cannot delete an image if it means that a tie point will remain without a matching point on another image For example if a tie point is collected on two images neither image can be removed unless the tie point is removed On the other hand if the tie point is collected on three images then one image can be removed without affecting the others To remove an image from the project 1 In the main menu click Utilities 2 Click Remove Image Photos 3 Select Uncorrected Photos to select a raw image Ortho Photos to select an orthorectified image or geometrically corrected image Epipolar Photos to select an epipolar pair 4 Select one or more image from the list 5 Click Remove photo from project to remove the image from the project but leave the image on the disk Remove photo from project and delete files on disk to delete the image from both the project and the disk 6 Click Close Re connecting Offline Images An image with the status Offline often means that the image was deleted
221. of lines in Y Size to specify the size of the frame However once the Mosaic file is created you cannot move the frame or edit the Mosaic Extents Mosaicking Images with a Background Value Other Than Zero OrthoEngine uses a background value of zero for orthorectified or geometrically corrected images so the Mosaic Area also has a background value of zero by default However images orthorectified or geometrically corrected outside of OrthoEngine may have a background value other than zero To mosaic images that were not processed in OrthoEngine you need to identify the background value of those images After you identify the background value OrthoEngine will not include that value when the images are added to the mosaic file Therefore the final mosaic will only contain valid data from the images You identify the background value on the Define Mosaic Area window in the Input Image Background Value box see step 5 in Defining a Mosaic Area on page 112 Mosaicking Images Automatically Although you can create your mosaic one image at a time by using Manual Mosaicking see Mosaicking Images Manually on page 115 most of the time you will use Automatic Mosaicking to do the bulk of the work and you will use Manual Mosaicking to edit portions of the mosaic file Some projects may require more editing than others such as those containing large bodies of water or urban areas with buildings leaning in different directions In
222. of the image pixels to the epipolar pixel The mode is the image pixel value that occurs the most frequently among the image pixels that will become one epipolar image pixel 10 Under Processing Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours 11 Click one of the following Generate Pairs to begin the process following the time set under Processing Start Time Use this option if you are using the epipolar pairs for 3 D Feature Extraction If you are using the epipolar pairs for Automatic DEM Extraction you can either use this option or Save Setup Save Setup to save the options chosen for batch processing with Automatic DEM Extraction When Save Setup is selected the option set under Processing Start Time is disregarded For more information see Extracting Digital Elevation Models from Epipolar Pairs on page 71 12 Click Close Re step in your project If you are using the epipolar images to generate a DEM see Extracting Digital Elevation Models from Epipolar Pairs on page 71 If you are using the epipolar images for 3 D Feature Extraction see Understanding 3 D Stereo Viewing and Editing on page 81 Extracting Digital Elevation Models from Epipolar Pairs The process of generating a digital elevation model DEM consists of several steps Convert the raw images into epipolar pairs Epipolar images are stereo pairs that
223. oints ground control points check points tie points and elevation match points in the image must have unique labels You can use the same Point ID for the same GCP in the overlap areas of different images In the list below the Point ID box click Ground Control Point GCP to use the GCP to calculate the math model Check Point CP to check the accuracy of the math model For more information see Troubleshooting the Math Model Solution on page 56 You can select Auto Locate and or Bundle Update to aid with collection For more information see Using Auto Locate on page 35 and Using Bundle Update on page 36 On the GCP Collection window under Auxiliary Information you may have additional features available to you depending on the math model that you selected Ifyou chose the Rational Function math model you can select in the No of Coefficients list the number of coefficients you want to use to calculate the math model For more information see Understanding the Rational Functions Math Model on page 6 Ifyou chose the Polynomial math model you can select in the Polynomial Order list which polynomial that you want to use to calculate the math model For more information see Understanding the Polynomial Math Model on page 7 Under Georeferenced Position in the Elev box type the elevation of the GCP or you can use a digital elevation model DEM to determine 36 PCI Geomatics
224. ojected onto the new output projection they are changed into Check Points so that they do not affect the computation of the math model 4 Inthe Output Pixel Spacing box type the x pixel size in the units meters feet or degrees used in the project 5 Inthe Output Line Spacing box type the y pixel size in the units meters feet or degrees used in the project For orthoimages and mosaics the Output Pixel Spacing and Output Line Spacing are the x and y resolution of your output images 6 Under GCP Projection select a projection type 7 Under GCP Projection type the projection string for example UTM 17 T D000 in the text box beside the Earth Model button or click Set GCP Projection based on Output Projection if your GCP projections are the same as your output projection If you do not know the projection string follow the same steps described under step 3 8 Onthe Set Projection window click Accept y If you change the values for the Output Pixel Spacing or Output Line Spacing all orthoimages created previously are reset automatically to None and should be regenerated at the new resolution Also the output mosaic is reset when the resolution changes The previous files are not removed from the disk but the status in the project file is reset to None rw step in your project For Aerial Photography Projects see Entering the Camera Calibration Data on page 24 For Satellite Orbital Projects see Impo
225. ollect the same GCP in each image by clicking Reference in a viewer collecting the GCP and then repeating the process for each image 2 s Tip If you are working in a project with a large volume of images we recommend that you enter the fiducial marks and ground control points for a limited number of images up to five complete the bundle adjustment for the math model and then check for errors before continuing It is easier to locate bad points on a few images than over the entire project To collect ground control points from vectors 1 On the OrthoEngine window in the Processing Step list select GCP Collection al 2 Click the Open new or existing photo icon to open an image For information how to open an image see Opening Images on page 17 3 On the OrthoEngine window click Vectors icon ES the Collect GCPs from 4 Onthe GCP Collection window the Point ID is generated automatically You can type a new label in the Point ID box however all points ground control points check points tie points and elevation match points in the image must have unique labels 5 In the list below the Point ID box click Ground Control Point GCP to use the GCP to calculate the math model Check Point CP to check the accuracy of the math model For more information see Troubleshooting the Math Model Solution on page 56 6 Youcan select Auto Locate and or Bundle Update to aid with collection Fo
226. ollection window under Photo Position or Image Position 9 Click Accept The GCP is added to the Accepted Points table 2 s Tip You can edit the error estimate in the boxes under Image Position to correspond to your ability to precisely identify a feature in the image For example if you use coarse imagery you can probably only measure to the closest pixel If you use imagery that was compressed or poorly scanned you may only be able to measure to the closest two pixels Even if you identify a GCP to the closest pixel the coordinate may only be accurate to so many meters Ho step in your project For projects using the Aerial Photography or Satellite Orbital math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Adding or Editing a Tablet OrthoEngine can work with any tablet that communicates using ASCII characters Most of the options used to configure the table can be found in the tablet s installation manual or user guide A tablet configured in ASCII mode reports actions and coordinates by sending a string of characters to the computer For OrthoEngine to interpret the strings of characters you must define the format that the tablet uses to create the string The format of the strings varies from tablet to tablet The tablet configurations are stored in tablet def in the etc folder where Geomatica is installed For more infor
227. ome overlap between the images Click Add when you are finished the cutline 4 Under Cutline Information the table displays the vertices collected to form the cutline To edit the cutline select a vertex in the viewer or in the table click Move Delete or Insert perform the edit and then click the same button again to end the edit 5 Click Finish 6 Inthe Blend Width list type or select the number of pixels on either side of the cutline used to blend the seam A Blend Width of three to five pixels is recommended You can see the results of the blend in the Mosaic Preview window For more information see Blending the Seams on page 117 Lr step in your project Continue with steps in Adjusting the Color Balance on page 116 Adjusting the Color Balance For more information about color balancing see Understanding Color Balancing on page 117 Continuing the steps from Collecting the Cutline on page 115 1 Under Mosaicking Steps click Color Balancing 2 Click New Area and drag a rectangle in the overlap area to select a match area Repeat as many times as necessary Select Show Mosaic Preview to see how each match area affects the image that you are adding to the mosaic 3 Brightness is available for projects using 8 bit channels It controls the range of values available in the lookup table computed from the match areas In the Dark End and Light End boxes type or select the values to determine the lo
228. ommon aei apita iien ia eiii 79 Exporting a Digital Elevation Model to a Text File nain nea nene nene nennen EE Eaa a EE EE AN nennen E NEE 80 Chapter 7 EDITING FEATURES IN 3 D STEREO Understanding 3 D Stereo Viewing and EditiNQ oooonnonnnnnnnnncccnnniccnnonccnnonnccnnrn eene nrren nri enne iners eterne n nene nennen nene 81 iv Viewing in 3 D Using Anaglyph Technology enn eene rre 82 Viewing in 3 D Using OpenGL Technology A A bete eee Uie 82 Using Epipolar Images for 3 D Stereo Editing nne nenen nnn ennnre enhn senes n nene entretenir nere enne nnns 82 Reducing EY A rate 83 Examining the 3 D Feature Extraction Work FlOW ooooonninnncccnnnconncoconnoccnonnrnncnnnnn nro n cnn rre rre 83 Selecting the Stereo Pall z A EO EDO ED tnt bo ddadasnsgdtatd Taaa ara E eE A Anaa 83 Navigating Within the 3 D Viewing Window sseeseseeneenen emm ene mennn rr 84 Moving the Stereo Cursor Pixel by Pixel netter reee tner 85 Moving the Stereo Cursor to Different Elevations sssseseeseeeneeenen nennen nnne nennen renes en nennen nn en erret nnne 85 Adjusting the Alignment in the Stereo Viewer ciiise eniinn teaiin tenter te rne dote 85 Creating a Lay IRE I 85 Changing the Projection When Creating a New Layer sssssseseseenen nee nennen nere en nrrs nennen rnit tenes n nne neris 86 Eat e l
229. ongitude Latitude units In the Upper Left boxes type the coordinates of the upper left corner of the DEM In the Lower Right boxes type the coordinates of the lower right corner of the DEM Click Generate DEM If you are generating a DEM from vectors you must select an interpolation method For more information about the methods see Understanding the Interpolation Methods for Vectors on page 68 Select OrthoEngine User s Guide 67 Chapter 6 Generating Digital Elevation Models Natural Neighbor Interpolation to use the Natural Neighbor algorithm to interpolate the DEM from points It is recommended for files that contain sparsely distributed or unevenly distributed points since it performs a more intelligent calculation than Finite Difference However it is not recommended for files that contain a large number of points since the calculations required will take considerable more time to process Finite Difference to use the Distance Transform and Finite Difference algorithms to interpolate the DEM from points It is recommended for files that contain evenly distributed points It can rapidly process an unlimited number of points Inthe No of Iteration list type the maximum number of times that the DEM is smoothed Inthe Tolerance box type the minimum difference in value required during smoothing to warrant another application 8 If the DEM is satisfactory click Accept DEM Understanding the Interpolat
230. onitors and glasses function in a similar way The advantages of using this technology You can view the images in full color t provides a more natural stereo viewing experience You may experience considerably less eye strain You can use single or double monitor configurations The 3 D effect is superior to the anaglyph technology The disadvantages of using this technology You need additional hardware to take advantage of this technology You may need to set your monitor at a lower resolution due to extra demands on the video card Since lower color depths can cause artifacts and refresh difficulties with OpenGL technology we recommend that you set your monitor to 32 bit or Full Color Display For effective stereo viewing the monitor s frequency should be at least 100Hz and the resolution should be greater than 1024 by 768 or as permitted by the graphics card Using Epipolar Images for 3 D Stereo Editing Using epipolar images while editing in three dimensional 3 D stereo editing can greatly improve your view of the images and can reduce the need to manually align the images For more information see Creating Epipolar Images on page 69 82 PCI Geomatics Reducing Eyestrain Reducing Eyestrain Many people experience difficulty such as eyestrain and fatigue when they work in a 3 D environment The following are a few tips to avoid discomfort Constantly adjust the focus in the 3 D viewer
231. oordinates and assigns the value to the output coordinates The 16 Pt SinX X resampling option determines the gray level from the weighted average of the 256 closest pixels to the specified input coordinates and assigns the value to the output coordinates The resulting image from using either of these methods is sharper than one produced by Bilinear Interpolation and it does not have the disjointed appearance produced by Nearest Neighbor Interpolation However since the gray level values are altered by these methods image classification processes should be performed before the interpolation OrthoEngine User s Guide 105 Chapter 8 Correcting Your Images Average Filter The Average Filter resampling option determines the gray level from the mean of all pixels in a square or rectangular frame surrounding the input coordinates and assigns the value to the output coordinates The mean is determined by calculating the sum of all pixels in the frame and then dividing by the number of pixels in the frame To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data This method smooths the appearance of the image You control the size of the frame with the Filter Size option by typing the number of pixels in width in the X box and the number of pixels in length in the Y box Median Filter The Median Filter resampling option determines the gray level from the median value o
232. or Chips in a Database on page 42 and start with step 2 Type the chip ID in the Chip ID box under Current Chip Info and then press ENTER Click More Info to view detailed header and chip information Creating a New Chip Database from an Existing Database After searching an existing chip database you can save a copy of the selected chips in a new database To create a chip database from the chips 1 Perform a search For more information see Searching the Chip Database on page 139 2 In the main menu click Utilities 3 Click New from search list 4 In the New chip database name box type the path and filename for the new database or click Browse to select the file 5 Click Create Database Merging Chip Databases Copies of each chip database are combined into one chip database To merge two chip databases 1 In the main menu click Utilities 2 Click Merge image chips 3 Inthe 1st database box type the path of one of the chip databases or click Select to choose the file 4 Inthe 2nd database box type the path of the other chip database or click Select to choose the file 5 In the Merged database box type the path and filename of the new chip database or click Select to choose a location 6 Click Perform Merge 7 Click Close Deleting a Chip Database To delete a chip database from the disk 1 In the main menu click Utilities 2 Click Delete OrthoEngine User s Guide
233. or each image and distributes the data with the images This is only available for IKONOS imagery QuickBird imagery or images that are distributed in NITF 2 0 format with the RPC image support data included in the NITF file Space Imaging distributes the IKONOS Ortho Kit imagery with an auxiliary text file called an Image Geometry Model IGM containing the coefficients The coefficients are automatically imported into OrthoEngine However adding GCPs can refine the math model of a project using IKONOS imagery see Using the Right Math Model with IKONOS Data on page 6 quote Using more coefficients will result in a more accurate fit in the immediate vicinity of the GCPs but it may introduce new and significant errors in the image away from the GCPs The errors introduced into the imagery may be worse than the original errors that needed correcting We recommend using 10 coefficients since it usually produces the best results The three ground coordinates and two image coordinates are each offset and scaled to have a range from 1 0 to 1 0 over the image For each image the defined ratios of polynomials have the form Kong Pl Xn Yn Zn Q2 Xn Yn Zn colam P2 Xn Yn Zn Q2 Xn Yn Zn where Row n Normalized row index of pixel in image Col n Normalized column index of pixel in image Xn Yn Zn Normalized ground coordinate values The polynomials P and Q have the form ml m2 m3 EN 1 j K P x Y iik xn Yn Zn 1
234. or use with Geometric Correction When you are using simple math models the main advantage of a higher Sampling Interval is processing speed Depending on the complexity of the math model a higher interval would likely have less effect on the final accuracy than rigorous math models that use a DEM Understanding the Status Descriptions Status descriptions for images under Available Photos or Available Images The status of the image determines which images can be processed No model You need to compute the math model before you process the image see Performing the Bundle Adjustment for Rigorous Math Models on page 55 or Understanding the Solution for Simple Math Models on page 56 Stale model You have changed information in the project that may have affected the math model You should to recompute the math model before you process the image see Performing the Bundle Adjustment for Rigorous Math Models on page 55 No Ortho The model is up to date and a corrected version of the image was not found You can select the image and move it to Photos to Process Ortho stale A corrected version of the image was found but it does not match the current math model You can select the image and move it to Photos to Process Ortho done A corrected version of the image was found and it matches the current math model You do not need to reprocess the image Status descriptions for images under Photos to Process or Images
235. or when you do not have surveyed elevation measurements for your ground control points GCPs and or tie points You should make sure that the DEM will provide the level of accuracy that you require for your project and that it includes the features that you are trying to analyse For example When you want an orthorectified image that is accurate to 0 01 meters a DEM with 1 kilometer resolution will probably not deliver the accuracy you need If you want to analyse highway overpasses a DEM that was smoothed and resampled to 30 meters will not provide the details that you need If you want a smooth low resolution orthorectified image a DEM containing fine features such as buildings may contain too much detail Besides providing a source of elevation the DEM itself has many uses For example Geologists use DEMs to identify geological structures in topography Mapping agencies use DEMs as the source of topographic information and contour lines for maps Environmentalists use DEMs to identify risk areas and flow patterns Disaster management agencies use DEMs to identify flood risk areas and to determine accessibility Telecommunications companies use DEMs to identify regions of visibility for radio or cell towers They can also use the texture of the DEM to predict how the terrain can effect signal strength and reflection Re step in your project See one of the following Using Rasters to Gener
236. ordinates or click a format in the Example Formats list For more information see Understanding Format Descriptions for Text Files Containing GCPs on page 133 Click Apply Format Click Accept Click Close export the GCPs to a new segment in the image file In the main menu click Options Click Export Click GCPs Select file to export In Segment Information click Save to new segment in photo file In the Name box type the label of the segment In the Description box type a description for the segment Click Export export the GCPs to an existing segment In the main menu click Options Click Export Click GCPs Select file to export In Segment Information click Save to existing segment in photo file 130 PCI Geomatics Exporting the Exterior Orientation 6 Select segment 7 Click Export Exporting the Exterior Orientation When you export the exterior orientation to a text file the resulting file contains the x y and z coordinates of the sensor the Omega Phi and Kappa values of the sensor and the Photo ID of the image For more information about exterior orientation see Understanding Exterior Orientation on page 26 To export the exterior orientation to a file 1 Inthe main menu click Options 2 Click Export 3 Click Ext Orientation 4 In Report File type a path and filename with the extension txt or click Select to choose a file 5 Click Append to
237. orrected images and join them to form a mosaic If you do not have an existing DEM for your project area you can generate a DEM from image stereo pairs in your project and use it to orthorectify your images Figure 1 1 Simplified Work flows STEP 1 Rational Functions Polynomial Thin Plate Spline Set projection Import images Enter sensor data STEP 2 Collect GCPs Collect GCPs Collect tie points Compute the math model Satellite Orbital Aerial Photograph None deliverable Orthorectification Digital or geometric elevation correction model DEM 3 D feature extraction vectors OrthoEngine User s Guide Chapter 1 Using OrthoEngine How To Contact Us Software support is available from PCI Geomatics to assist you with technical or application difficulties Please call your PCI Geomatics representative or authorized reseller to obtain more information about software support Before you contact us please have the following information ready Your customer number Product name Product version Computer system and O S version Exact error message if any Steps to re create the problem Your phone number fax number and e mail address By telephone 1 877 RING PCI 1 877 746 4724 North America 800 2746 4724 toll free from the United Kingdom The Netherlands Belgium and France 44 1491 579 910 Direct to our European support office 1 905 7
238. ou may have additional features available to you depending on the math model that you selected Ifyou chose the Rational Functions math model you can select in the No of Coefficients list the number of coefficients you want to use to calculate the math model For more information see Understanding the Rational Functions Math Model on page 6 Ifyou chose the Polynomial math model you can select in the Polynomial Order list which polynomial that you want to use in your project For more information see Understanding the Polynomial Math Model on page 7 Under Auxiliary Information click Load In the Image Chip Database Selection window select the chip database file Click Open In the OrthoEngine ChipDatabase window do one of the following Click the button type the chip ID or chip sequence number and then click OK Use the navigation buttons to select chip Click Search Criteria to narrow the search for chips to a manageable number of chips and then use the navigation buttons to select chip For information about searching the chip database see Searching for Chips in a Database on page 42 Typethe chip ID in the Chip ID box under Chip Information and then press ENTER Detailed information about the currently selected chip appears under Chip Information in the OrthoEngine ChipDatabase window Click More Info to view detailed header and chip information OrthoEngine User s Guide 41 Chapter 5
239. page 58 56 PCI Geomatics Troubleshooting the Math Model Solution Residual errors do not necessarily reflect errors in the GCPs or tie points but rather the overall quality of the math model In other words residual errors are not necessarily mistakes that need to be corrected They may indicate bad points but generally they simply indicate how well the computed math model fits the ground control system quote In Rational Functions Polynomial and Thin Plate Spline projects images are not connected together with tie points Therefore the math model and the resulting residual errors are calculated for each image separately If you selected the Thin Plate Spline math model for your project the residual errors will always indicate zero Use Check Points to check its accuracy Another way to verify the quality ofthe model is to collect some GCPs as Check Points Check points are not used to compute the math model but OrthoEngine calculates the difference between their position and the position determined by the model and includes the error in the Residual Errors report Therefore the Check Points provide an independent accuracy assessment of the math model In most projects you should aim for the residual errors to be one pixel or less However you should also consider how the resolution of the image the accuracy of your ground control source and the compatibility between your ground control source and the images can
240. page 89 Changing the Priority of a Layer When two or more vector layer overlap it may be difficult for you to identify the vectors that you want The layers in the 3 D viewer are displayed one on top of the other in the same order as they appear in the Vector Layer Information table As layers are added to the 3 D viewer vectors are covered by other vectors The topmost row in the Vector Layer Information table contains the layer with the highest priority which means that its vectors are not covered by any other layer Moving the layer that you are working on to the highest priority in the 3 D viewer can help you to see the vectors on that layer more clearly To change the priority of a layer 1 Inthe Vector Layer Information table click the layer that you want to move up or down in priority 2 Click the Change Priority arrows to position the layer in the table The top row is the layer with the highest priority and the bottom row is the layer with the lowest priority Changing the Visibility of a Layer You can display or conceal vector layers individually or collectively The check mark in the Visible column in the Vector Layer Information table indicates a layer that is displayed in the viewer To conceal or display an individual layer right click in the Visible column of the layer To conceal all the layers in the Vector Layer Information table click Hide All To display all the layers in the Vector Layer
241. pe 6 OrthoEngine uses the orbital data to sort and join the correct tiles so you can enter the files in any order In the Image File boxes type the paths and filenames of your imagery or click Browse to select the files 7 In the Output Filename box type the path and filename for your reassembled image or click Browse to select a location 8 Click Stitch Once the stitching is completed successfully you have the option of keeping or removing the tiles from your project Setting the Automatic Backup The default backup saves the project every 10 minutes in a temporary file with a bk extension in the same folder as the project The backup file is deleted when you exit OrthoEngine normally You can change the frequency of the backup as required To set the Automatic Backup timer 1 Inthe main menu click Options 2 Click Auto Backup 3 Select Auto Timed Backup to enable the timer 4 In enabled type the number of minutes and seconds to elapse between backups 5 In Auto Backup File type the filename of the backup file 6 Click Close Setting Default Ground Control Point Elevation Units After you set the projection for your project the same projection and units of measurement for the elevation are set by default for ground control point GCP collection In some cases however the units of measurement in the digital elevation model DEM or other source that you are using to extract the elevation for the GCPs may
242. play them in three dimensions 3 D over an image and use them for quality control or editing Choosing between using vector points or contour lines is a matter of personal preference Vector points are easier to edit than contour lines because you have fewer points to analyse Contour lines offer a more intuitive view ofthe terrain but you have more points to edit For more information about contour lines see Extracting Contour Lines from a Digital Elevation Model on page 96 To extract a vector grid from a DEM 1 Onthe OrthoEngine window in the Processing Step list select 3 D Operations 2 Click the Extract Vector Grid from DEM icon 3 On the Extract Vector Grid window under Input DEM in the File box type the path where the DEM is found or click Browse to select the file 4 Inthe Channel list click the DEM channel or click Select 5 Inthe Failure Value box type the failed pixel value 6 In the Background Value box type the background pixel value 7 Under Input Window click Full Image to extract a vector grid from the entire DEM Window to extract a vector grid from a specific area In the Offset boxes type the pixel and line coordinates of the upper left corner of the area and in the Size boxes type the number of pixels and lines to specify its size OrthoEngine User s Guide 95 Chapter 7 Editing Features in 3 D Stereo 8 10 11 12 Under Output Grid in the File box type th
243. points but rather the overall quality of the math model In other words residual errors are not necessarily mistakes that need to be corrected They may indicate bad points but generally they simply indicate how well the computed math model fits the ground control system For more information see Troubleshooting the Math Model Solution on page 56 Quote Depending on the math model that you chose the features available may vary To generate a Residual Report 1 On the OrthoEngine window in the Processing Step list select Reports 2 Click the Residual report icon m 3 Under Residual Units click the measurement unit that you want displayed in the report 4 Under Show Points click All to display all the points collected e GCPs Check Pts to display only the ground control points and the check points Tie Points to display only the tie points Stereo GCPs to display the points that appear on more than one image 58 PCI Geomatics Editing Points in the Residual Report 5 Under Show in click All Photos to display all the images in the project Click an image in the table under Photo ID or type the image s identification in the Selected Photo ID box Click Selected Photo to display one image in the project 6 Under Sort by click Residual to order the residual errors from the highest to the lowest value Data Snooping to order the normalized residual errors from highest to
244. polation 105 Noise Removal 77 Radar Enhanced Frost 108 Radar Enhanced Lee 110 Radar Gamma filter 107 Radar Kuan 109 SIN 8 Pt and 16 Pt SinX X 105 Smooth filter 78 User Defined filter 106 Finite Difference 68 flying height 55 Focal Length 21 24 Forests 78 Format Description 49 Format Descriptions 133 Format String 49 61 Format string rules 60 Format Strings for tablet 60 FORMAT format string 61 G gaps in DEM See Interpolate Holes Gaussian Filter 106 Gaussian filter 78 GCP change color in chip 43 change default color 131 choosing quality points 34 collect GCPs from chip database 40 collect GCPs from chip database automatically 43 collect GCPs from geocoded image 37 collect GCPs from tablet 45 47 collect GCPs from vectors 39 collect GCPs manually 36 defaults for GCP elevation datum 128 display layout 54 export 130 import from file 49 minimum number 34 setting GCP Elevation Units 127 understanding 33 using GCPs to generate DEM 64 GCP Projection 13 GDB 1 generate epipolar images 69 generate Project Report 132 Generating Reports Chip Manager 140 Generic Database See GDB generic image file 17 GEO product 18 geocode DEM 79 automatic batch processing 71 geocoded image 37 Geometric Correction processing the images 101 resampling options 104 Sampling Interval 102 set channel type 129 Status Descriptions 103 understanding 100 geometry for stereo pairs 69 geometry of the camera 55 OrthoEngine User s G
245. put DEM file 67 define the size of the frame on tablet 47 defining the search parameters for chip database 42 defragment the chip database Chip Manager 140 Degree 28 Degrees Minutes Seconds See DMS delete a chip database Chip Manager 139 delete a chip from a chip database Chip Manager 140 delete a layer 94 delete line 90 Delete Point 59 146 PCI Geomatics delete vertex 90 DEM bounds 67 Cloud Covered Areas 79 converting the datum 126 create epipolar images 69 Detail 74 editing 71 74 75 76 77 78 editing strategies 78 Erode Holes 78 export to text file 80 extents 73 Finite Difference 68 Forests 78 from contours 66 from epipolar pairs 71 from points 66 from raster file 64 from stereo pairs 69 from TIN 66 from vectors 65 67 Gaussian filter 78 geocode 71 79 Interpolate 78 Lakes 78 Median filter 78 merge DEM raster files 64 Natural Neighbor Interpolation 68 No of Iterations 68 Noise 79 Noise Removal 77 output 67 Pixel Sampling 74 replace elevation values under mask 76 resolution 67 size 67 Smooth filter 78 Switching between image and DEM 75 Tolerance 68 understanding 63 Urban Areas 78 use for elevation of GCPs 36 38 40 42 48 51 53 54 using GCPs tie points and elevation match points 64 using rasters vectors or control points 67 Detail in DEM 72 74 determining pixel value 73 determining the best solution for the math model 56 digital camera calibration 21
246. r 137 viewing geometry 55 visibility of layers 87 OrthoEngine User s Guide 157 W work flow 2 3 for 3 D feature extraction 83 Working Cache 30 working in 3 D 84 Y Y Scale Factor 24 Z Zoom Zoom 1 to 1 Image Resolution 122 Zoom In 122 Zoom Interactive 122 Zoom Out 122 Zoom to Overview 122 158 PCI Geomatics
247. r Data Output in the PCIDSK Filename box type the name of the output file 8 Inthe Scene Description box type a description of the file optional 9 Inthe Report Filename box type the name ofthe file where the report will be saved 10 Click Read ex step in your project See Collecting Control Points and Computing the Math Models on page 33 Reading Satellite Data from a Tape OrthoEngine reads the raw satellite data saves the imagery into a PCIDSK file and adds a binary segment containing the orbit information to the file Before reading image data from a magnetic tape the tape must be mounted For information about mounting tape drives see the Installing PCI Software User Guide To read satellite data from a tape 1 On the OrthoEngine window in the Processing Step list select Data Input 2 Click the Read Tape icon 3 Under Data Source in the Tape Format box select the sensor and distribution format combination that corresponds to your data 4 Inthe Tape Device box type the path to the Tape drive On Windows systems the Tape Device is the drive letter where the tape drive is mounted On Unix systems Tape Device is the name of the directory where the tape drive is mounted 5 Clickthe Requested Channels buttons corresponding to the channels that you want import Select at least one channel For each PCIDSK file that you create all the selected channels must have matching spatial resolution For sate
248. r more information see Using Auto Locate on page 35 and Using Bundle Update on page 36 7 Under Auxiliary Information you may have additional features available to you depending on the math model that you selected Ifyou chose the Rational Function math model you can select in the No of Coefficients list the number of coefficients you want to use to calculate the math model For more information see Understanding the Rational Functions Math Model on page 6 Ifyou chose the Polynomial math model you can select in the Polynomial Order list which polynomial that you want to use in your project For more information see Understanding the Polynomial Math Model on page 7 OrthoEngine User s Guide 39 Chapter 5 Collecting Control Points and Computing the Math Models 8 Under Auxiliary Information click Load 9 In the Database File Selection window select the vector file Click Open 10 In the File window select the database vector segment and click Load or Load amp Close If you want to choose multiple layers select a segment and click Load for each layer 11 Ata zoom level where you can see the detail in the Vector File window position the cursor precisely on the feature that you will use as a ground control point GCP and click Use Point The geocoded Easting and Northing coordinates transfer to the GCP Collection window 12 On the GCP Collection window under Georeferenced Position i
249. r the chip viewer On the PCI ImageChipsManager window select RGB color bands or individual bands in black and white in the Imagery list as required Switching between the Chip and the Overview On the PCI ImageChipsManager window click Chip to view only the chip or click Overview to see more of the area surrounding the chip Collecting the Chip To collect a chip from an image 1 Open the source image see Selecting the Source for the Chips on page 136 At a zoom level where you can see the detail in the source image position the cursor precisely on the feature that you will use as a GCP Click New chip On the viewer displaying the source image click Chip Size and specify the size of the chip For more information see Determining the Size of the Chip on page 137 On the PCI ImageChipsManager window click Accept GCP from cursor The coordinates of the GCP in the source image are transferred to the window under Ground Control Point Information 6 In Save Option click Chip Only if you want to save the chip without the overview Chip and Overview if you want to save the chip with the overview In the list select the size of the overview window The overview provides a view of the area surrounding the chip 7 Inthe Chip ID box type the label for the chip 8 Youcan extract the elevation for the GCP in two ways Onthe PCI ImageChipsManager window click Select near the bottom of the wi
250. ransformation between the image space and the ground space It uses principles related to photogrammetry orbitography geodesy and cartography The model reflects the physical reality of the complete viewing geometry and reflects all the distortions generated during the image formation such as those caused by The platform position velocity and orientation The sensor orientation integration time and field of view The earth geoid ellipsoid and relief The cartographic projection ellipsoid and cartographic As a result of this integration the modelling equations are simple and straightforward with few unknowns Each of the unknowns is the combination of several correlated variables of the viewing geometry so the number of unknowns is reduced to an independent set The equations are then solved with few ground control coordinates and with tie points if more than one image is used You can create a project using images acquired from one satellite or from a combination of images from different satellites The accuracy of the Satellite Orbital Math Model is approximately one third of a pixel for VIR satellite images and approximately one pixel for radar images when quality ground control coordinates are used Dr Toutin proved the accuracy of this math model by testing it using many different images of different areas and relief Using the Right Math Model with IKONOS Data Space Imaging distributes IKONOS data in a var
251. rea of interest to aid in identifying elevations For more information see Collecting Control Points and Computing the Math Models on page 33 Working with OrthoEngine As you follow instructions in the printed manual and the online help system you will find a special note that looks like this rw step in your project This note guides you through your project by indicating the next step according to the decisions that you make PCI Geomatics Working with OrthoEngine After you have gathered the information that you need to start your project as explained in Getting Started on page 2 you can open OrthoEngine see Starting OrthoEngine on page 9 and begin Step 1 Set up the project Select the math model Setthe projection Import images Enter data about the sensor geometry for rigorous models only Step 2 Compute the math model Collect the ground control points GCPs Collect the tie points Compute the solution of the math model Verify the math model solution Step 3 Generate the deliverable s Generate a digital elevation model DEM Generate three dimensional vectors 3 D Feature Extraction Orthorectify or geometrically correct the images Mosaic images Combining the deliverables As you can see in Figure 1 1 two of the deliverables are not only products in themselves but can also be used to form other products For example you can take your orthorectified or c
252. reas such as lakes often contain misleading elevation values so setting those areas to a constant value improves your model For some suggestions on how to handle common situations see Applying Tool Strategies for Common Situations in Digital Elevation Models on page 78 To edit the DEM 1 Open the 2D DEM Editing windows For more information see Opening the Digital Elevation Model Editing Windows on page 74 2 Inthe Failed box type the value assigned to the pixels that have no elevation values because the image correlation failed Some features will not be accessible unless you enter the failed value 3 Inthe Background box type the value assigned to the area outside the DEM which is usually a maximum or minimum value such as 150 or 999999 Some features will not be accessible unless you enter the background value 4 Create a mask For more information see Creating a Mask on page 75 5 Editthe DEM For more information see Replacing the Elevation Values Under a Mask on page 76 Filtering and Interpolating on page 77 and Applying Tool Strategies for Common Situations in Digital Elevation Models on page 78 D Click Save DEM back to file You can save the DEM at any time during the editing process The first time that you save the DEM you can choose to create a new channel for the edited DEM or to replace the original DEM He step in your project If you have not already geocoded the DEM see
253. resses the angles in degrees If a circle is divided along its radius into 360 equal parts a degree is the angle between two adjacent radii measured at the center of the circle Radian if the file expresses the angles in radians A radian is a unit used to measure angles where 2 pi radians equals the 360 degrees in a circle Therefore one radian equals approximately 57 29577951 degrees Grads if the file expresses the angles in grads A grad is a unit used to measure angles where 400 grads equals the 360 degrees in a circle Therefore a 90 degree right angle equals 100 grads DMS if the file expresses the angles in Degrees Minutes Seconds This angle unit is only available on the Import Exterior Orientation Data from Text File window DMS is a unit used to measure angles where a degree is divided into equal parts A circle contains 360 degrees Each degree is divided into 60 sections called minutes Each minute is also divided into 60 sections which are called seconds Therefore each angle is described by a number of degrees minutes and seconds In Accuracy enter the estimated error for orientation parameters in the X Y Z Omega Phi and Kappa boxes if available Accuracy only appears on the Import GPS INS Data from Text File window The data set or GPS INS sensors usually contain the estimated accuracies The estimated error values are used to automatically weight the exterior orientation data with GCPs and tie points dur
254. ribute Values on page 93 Assigning Attribute Values After you have designed the Attribute table you can enter the attributes for each vector in the selected layer For information about how to design the Attribute table see Designing the Attribute Table on page 92 To enter the values in the Attribute table 1 In the Vector Layer Information table select the layer containing the vectors that you want or select the feature in the viewer 2 In the Attribute table each row represents a vector in the selected layer In the row of the vector that you want click the field under the column of the attribute you want to enter The corresponding vector is highlighted in the 3 D viewer 3 Ifnecessary select the default data in the field and type the new value Press ENTER or click Accept The value is accepted and the default data is selected in the following field automatically Repeat step 3 until all the fields are satisfactory He step in your project See Saving a Layer on page 93 Saving a Layer You can add a new layer to an existing file or you can save the layer in a PCIDSK pix an ESRI Shape File shp or an AutoCad dxf format The layers that appear under Savable Vector Layers are the layers that you have available in the stereo viewer The layers that appear under Database Vector Segments are the layers that are saved in the file If you close the stereo viewer unsaved layers are discarded
255. rs or Control Points on page 67 Using Vectors to Generate a Digital Elevation Model OrthoEngine can calculate the elevations from vector layers to generate a raster digital elevation model DEM OrthoEngine uses raster DEMs to orthorectify images If your elevation data is stored as vectors such as contours points TIN or even a text file containing OrthoEngine User s Guide 65 Chapter 6 Generating Digital Elevation Models coordinates you can convert them into a raster DEM as long as the 3 vectors are in any of the supported formats Quote You can combine vectors from different layers and files to generate a DEM 4 Vector layers can contain Points A point is a single coordinate x y and z Lines A line is a start and end coordinate with points in between to 5 define the shape Polygons A polygon is a line with the same start and end coordinate forming an area with numerous points along the line to define its size and shape Contours A contour is a line formed by a set of points representing the same value of a selected attribute Contours are usually used to represent connecting points on the ground with the same elevation TIN A Triangulated Irregular Network TIN is a digital model of adjoining triangles formed from points selected on the terrain to represent an accurate model of the surface The TIN model can contain coordinates and other geographical data To import vector file
256. rstanding project work flows 2 Start Orbit Calculation 17 Status Descriptions 103 Stereo cursor understanding 81 using 84 stereo pairs of images 69 stitching image tiles 126 Stop Bits 46 49 61 STOP stop bits 61 Strategies for editing DEMs 78 Stream Mode 49 61 STREAM stream mode 61 strings of characters for tablets 48 subset chip database 139 Summary report Chip Manager 140 Super Structure IRS 18 Supported Satellite Formats 18 supported sensors 1 Supresoft 80 131 Switch Stream Mode 61 SWITCH switch stream mode 61 Switching between Chip and Overview 137 Switching between image and DEM 75 switching to stereo cursor 85 Switch stream Mode 49 Symbols 54 symmetric distortion See Radial Lens Distortion Sync Image Photo 124 Sync Image Photos 125 SYSTEMATIC geodetic processing 18 T tablet add or modify 48 ASCII mode 48 connect to 46 to collect GCPs 45 47 Tablet Configuration 48 60 tablet configurations 48 tablet definitions 61 Tablet Format Strings 60 Tablet Setup and Map Tie down 46 TABLET tablet number 61 Tail Trim 121 Tape Format 16 template for project 133 text file containing coordinates for DEM 65 Thin Plate Spline Math Model 8 minimum number of GCPs 34 Starting a project 12 understanding solution 56 three by three pattern 52 156 PCI Geomatics Three dimension vectors See 3 D Feature Extraction Threshold values 132 tie point change default color 131 choosing quality 52
257. rted to the text file OrthoEngine extracts the x y and z coordinates of every nth pixel and saves them in a file using an ASCII format For example typing in the Spacing box generates a file with the coordinates of all the pixels in the DEM Under Output DEM 1n the File box type the path where you will save the file or click Browse to select a location Select Require Supresoft DEM format if you are using the file with Supresoft products Click Export DEM 80 PCI Geomatics Editing Features in 3 D Stereo Understanding 3 D Stereo Viewing and Editing Your eyes see your surroundings from slightly different positions so each eye observes objects from different angles Your brain receives this information and unites these different views into one three dimensional 3 D image This allows you to perceive the depth and height of the objects in your surroundings Since your brain performs this process far better and faster that any machine OrthoEngine s 3 D editing features take advantage of your natural stereoscopic vision to provide an intuitive environment for you to interpret images Objects with height appear to lean away from the center of the image This is commonly referred to as relief displacement If you digitize features from the image even an orthorectified image the x and y coordinates will be offset from their true positions because of relief displacement By digitizing features in 3 D stereo your eyes will
258. rthing gt 05 N Longitude og Lat Latitude Accept Delete New Point 12 At azoom level where you can see the detail in the raw image position the cursor precisely on the feature that you will use as a GCP and then click Use Point The pixel and line coordinates from the raw image appear in the GCP Collection window under Photo Position or Image Position 13 Click Accept The GCP is added to the Accepted Points table You can edit the error estimate in the boxes under Image Position to correspond to your ability to precisely identify a feature in the image For example if you use coarse imagery you can probably only measure to the closest pixel If you use imagery that was compressed or poorly scanned you may only be able to measure to the closest two pixels Even if you 50 PCI Geomatics Using a Digital Elevation Model to Set Ground Control Point Elevation identify a GCP to the closest pixel the coordinate may only be accurate to so many meters He step in your project For projects using the Aerial Photography or Satellite Orbital math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Using a Digital Elevation Model to Set Ground Control Point Elevation If you chose the Aerial Photography Satellite Orbital Rational Functions or Thin Plate Spline math models you can use a digital
259. rting and Viewing Images on page 15 For Rational Functions Polynomial and Thin Plate Spline Projects see Collecting Control Points and Computing the Math Models on page 33 For Mosaic Only see Importing Images or Photographs into Your Project on page 15 14 PCI Geomatics Importing and Viewing Images Importing Images or Photographs into Your Project You can import satellite images without ephemeris data scanned images from aerial photographs digital images and video images by using the following method To import satellite images with ephemeris data see Reading Satellite Images from a CD or a Digital Distribution Format on page 15 To import images into your project 1 On the OrthoEngine window in the Processing Step list select Data Input or GCP Collection al 2 Click put the Open new or existing photo icon 3 Click New Photo 4 Inthe Database File Selection window select the images that you want to import into your project You can use SHIFT Heft click or CTRL left click to select multiple files 5 Click Open UN CHAPTER M A BN x S N SS TA N KSN fos step in your project For photographs see Collecting Fiducial Marks Manually on page 25 For Mosaic Only projects see Defining a Mosaic Area on page 112 For other projects see Understanding Ground Control Points on page 33 W Reading Satellite Images from a CD or a Digital Distribution Format OrthoEng
260. s a numeric value ending with text the text is ignored For example N or W in Latitude and Longitude values are ignored therefore use a negative sign instead Tip Since latitude north south usually appears before the longitude east west use YX instead of the more common XY 134 PCI Geomatics Creating a Chip Database Understanding the Chip Manager A chip database is a compilation of individual image samples called chips usually measuring 256 pixels by 256 pixels or smaller Each image section contains an accurate geocoded location and metadata such as which sensor it was generated from the date it was acquired the viewing angle and so on These chips can be used to collect ground control points GCPs You can visually match a feature in the raw image that you are georeferencing and use the coordinates from the chip database as a GCP or use the chips to automate the collection of GCPs For more information see Collecting Ground Control Points from a Chip Database Manually on page 40 With the Chip Manager you can create new chip databases add or remove chips from existing chip databases and merge different chip databases You can use the chips to collect ground control points GCPs on the raw images in your project as explained in Collecting Ground Control Points from a Chip Database Manually on page 40 LM Pe Opening the PCI Chip Manager To open the Chip Manager choose one of th
261. s to generate a DEM 1 On the OrthoEngine window in the Processing Step list select Import amp Build DEM 2 Click one of the following DEM from vectors points Anc DEM from contours A DEM from TIN On the Input Vector Layer Selection window in the Vector File box type the path of a vector file or click Select to select a file The vector layers from the file appear under Input File Vector Layers Under Input File Vector Layers click the layers of your choice and click the arrow The selected layers that will form the DEM appear under Set of Vector Layers to Interpolate To add vectors from other files repeat steps 3 and 4 In the Data Type list select the type of vector in the layer Click Points for a layer containing only points or one vertex Contours for a layer of vector lines with elevation values 3D Lines for a layer with three dimensional 3 D breaklines or features Valleys 2D for a layer of two dimensional 2 D breaklines without elevation values that is used to represent valleys Ridges 2D for a layer of 2 D breaklines without elevation values that is used to represent ridges Cliffs 2D for a layer of 2 D breaklines representing cliffs which are treated as a local discontinuity The interpolated elevations from either side of the breaklines may be radically different TIN for a layer of 3 D breaklines using the TIN model The 2 D layers provide additional constra
262. see Troubleshooting the Math Model e Solution on page 56 i Elevation Elev 2 000 m pag Easting 0 5 E 6 You can select Auto Locate and or Bundle Update to aid with Northing NS lection F inf Using Auto Locate 35 Longitude gt Long Lat Latitude collection For more information see Using Auto Locate on page s and Using Bundle Update on page 36 Aen Debo Now Poi 7 Under Auxiliary Information you may have additional features 13 At azoom level where you can see the detail in the raw image position available to you depending on the math model that you selected the cursor precisely on the feature that you will use as a GCP and click Use Point Ifyou chose the Rational Function math model you can select in the No of Coefficients list the number of coefficients you want The pixel and line coordinates from the raw image appear in the GCP to use to calculate the math model For more information see Collection window under Photo Position or Image Position Understanding the Rational Functions Math Model on page 6 Ifyou chose the Polynomial math model you can select in the FE CAEP Serene Polynomial Order list which polynomial that you want to use in The GCP is added to the Accepted Points table your project For more information see Understanding the Polynomial Math Model on page 7 G 5 YA 8 Under Auxiliary Information click Load s Tip You can edit the error
263. set see Entering the Camera Calibration Data on page 24 Defining Radial Lens Distortion Radial Lens Distortion is the symmetric distortion caused by the lens due to imperfections in curvature when the lens was ground In most cases the errors introduced by radial lens distortion around 1 to 2 um are much smaller than the scanning resolution of the image around 25um Entering the values may significantly increase the processing time while contributing very little value to the final product The values for the Radial Lens Distortion may be provided to you as RO through R7 coefficients or in tabular format The equation for the lens distortion is delta r RO R1 r R2 r R3 r RA r R5 r R6 r84 R7 r7 where r radial distance from the center of the image RO to R7 radial distortion coefficients If you are using a USGS camera calibration report the coefficients are given as K0 K1 K2 K3 and K4 which correspond to R1 R3 R5 and R7 K4 is discarded since it is usually zero The radial lens distortion parameter is optional and the coefficients may or may not appear in the camera calibration report To enter the coefficients see Entering the Camera Calibration Data on page 24 If you have a table of distortion pairs click Compute From Table in the Standard Aerial Camera Calibration Information window In the Distance Units list select a unit Enter a value in the Radial Distance box and the Radial D
264. st vertex positioned is the end point When you select an existing vector the stereo cursor snaps to the nearest vertex in that vector If you add a vertex to the existing line or polygon the new vertex is added at the location where you clicked It will connect to the last selected vertex and the next vertex following the sequence that the original vector was created If the last selected vertex is the end point of a line the vertices that you add will extend the line If you add a vertex to a point the point is converted into a line To insert a vertex 1 Move the pointer to the 3 D viewer and press ESC to switch to the stereo cursor 2 Click the vertex that precedes the location where you want to place the new vertex For information about how to select a vector see Using the Vector Editing Tools on page 90 3 Click Insert Vertex or press INSERT 4 Position the stereo cursor precisely on the location where you want to place the new vertex Adjust the position not only in x and y but also in Z You can also use Snap to Vertex or Snap to Line to position the cursor For more information see Using Snap to Vertex on page 90 and Using Snap to Line on page 90 5 Click to insert one or more vertices Ifthe vector is not reacting as expected click Undo and then Accept Try the process again by selecting the vertex beside the one you selected before Remember vertices inserted into the vector are added following the
265. t of a first order transformation depends on the number of GCPs One GCP produces a translation for x and y only Two GCPs produce a translation and a scaling change for x and y if the pixel geometry is not linear in the x or y dimension If it is linear meaning that the two GCPs have the same x or y coordinate producing a scaling factor of zero it produces only a translation If the scaling factor is greater than zero it may produce a flip in the x and or y dimension Three or more GCPs produce a translation scale change and or rotation for x and y a full first order transformation Quote A higher order polynomial will result in a more accurate fit in the immediate vicinity of the GCPs but it may introduce new and significant errors in the image away from the GCPs The errors introduced into the imagery may be worse than the original errors that needed correcting Understanding the Thin Plate Spline Math Model The Thin Plate Spline Math Model is a simple math model in which all the collected ground control points GCPs are used simultaneously to compute a transformation The warping is distributed throughout the image with minimum curvature between the GCPs becoming almost linear away from the GCPs The Thin Plate Spline Math Model fits the GCPs exactly Therefore a GCP can be added in an area where the transformation is not satisfactory However this also means that the math model does not provide direct means of dete
266. t you want to use 2 Inthe Bulldoze a Line Width list type or select the thickness of the line 3 Click Bulldoze Using Value 4 Drag the cursor over the area that you want to edit Filtering and Interpolating Use the filters available under Filtering and Interpolation to eliminate failed or incorrect values in your DEM You can apply each filter repeatedly to achieve a cumulative effect and in different combinations to obtain the results that you want You can limit the effect of the selected filter to a specific area by creating a mask and clicking Apply Under Mask or you can distribute the effect throughout the DEM by clicking Apply to Entire DEM Noise Removal Noise refers to pixels containing distorted or failed values Since pixels adjacent to failed pixels tend to contain incorrect values as well Noise Removal uses two filters to identify failed pixel values and their surrounding pixels The first filter calculates the average and variance of the eight elevation values immediately surrounding each pixel excluding failed and background pixels If the center pixel is more than two standard deviations away from the average it is replaced with the failed value The second filter counts the number of failed values immediately surrounding each pixel If five or more failed pixels border the center pixel then the center pixel is also set to a failed value OrthoEngine User s Guide 77 Chapter 6 Generating D
267. t you want to apply to the image Radar Enhanced Frost Filter The Radar Enhanced Frost Radar Enh_Frost Filter resampling option determines the gray level for each pixel by computing the weighted sum of the center pixel value the mean value and the variance calculated in a circular frame surrounding the pixel To filter pixels located near the edges of the image edge pixel values are replicated to produce sufficient data This filter is used primarily to suppress speckle It smooths image data without removing edges or sharp features in the images while minimizing the loss of radiometric and textural information In homogeneous areas speckles are removed using a low pass filter In areas containing isolated point targets the filter preserves the observed value In heterogeneous areas speckles are reduced by convolving the image with a circular kernel The resulting gray level value R for the smoothed pixel is R Im for Ci lt Cu R Rf for Cu lt Ci lt Cmax R Ic for Ci gt Cmax Where Rf is the result of convolving the image with a circularly symmetric filter whose weighting values M for each pixel is M exp A T where A Damping Factor Ci Cu Cmax Ci Ci S Im Cu SQRT 1 Number of Looks Cmax SQRT 1 2 Number of Looks Im mean value of intensity within the frame S standard deviation of intensity within the frame T the absolute value of the pixel distance from the center pixel to its n
268. ta 92 93 move vertex or point 92 navigating the 3 D viewer 84 OpenGL technology 82 reducing eyestrain 83 save a layer 93 select a 3 D stereo pair 84 Shortcuts for the 3 D viewer 94 Snap to Line 90 Snap to Vertex 90 understanding 81 undo 92 vector editing tools 90 work flow 83 3 D glasses advantages and disadvantages 82 3D Lines 66 3 D stereo pair selecting 84 8 Bit Unsigned 112 129 143 A Accepted Elevation Match Points 65 accuracy of the math model number of GCPs 34 Adaptive 121 add a tablet 48 Add image to mosaic 115 116 Add lines 88 Add points 88 Add polygons 89 Add to DEM 65 Aerial Camera 9 Aerial Photography Math Model 5 minimum number of GCPs 34 Starting a project 9 understanding solution 55 affine model 43 Albany 27 aligning images in 3 D 85 Anaglyph technology 82 anchor the reference frame around point 45 angular orientation of the camera 55 Applanix 27 ASAR 10 DEM from stereo pairs 69 intro to OrthoEngine 1 minimum number of GCPs 34 supported formats 18 understanding Satellite Orbital Math Model 5 ASCII string 60 ASCII n 60 ASTER DEM from stereo pairs 69 HDF format 18 intro to OrthoEngine 1 joining tiles 126 minimum number of GCPs 34 selecting left and right images 69 stitching 126 supported formats 18 understanding Satellite Orbital Math Model 5 Auto Locate 35 AutoCad 93 Automatic Backup 127 automatic bundle adjustment See Bundle Update automatic correlation 35 Automa
269. tal math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Collecting Ground Control Points from a Chip Database Manually A chip database is a compilation of individual image samples usually measuring 256 pixels by 256 pixels or smaller Each image sample contains an accurate geocoded location and metadata such as which sensor it was generated from the date it was acquired and the viewing angle These image samples called chips can be used to collect ground control points GCPs You can visually match a feature in the raw image that you are georeferencing and use the coordinates from the chip database as a GCP or use the chips to automate the collection of GCPs For more information see Collecting Ground Control Points from a Chip Database Automatically on page 43 If you have several images open you will notice that one image resides in a viewer labelled Working while the others are labelled Reference The GCP Collection window collects and displays the GCPs from the 40 PCI Geomatics Collecting Ground Control Points from a Chip Database Manually image in the Working viewer only Click the Reference button to switch the viewer to Working You can collect the same GCP in each image by clicking Reference in a viewer collecting the GCP and then repeating the process for each image Up If you are working in a pro
270. te that either the coordinates from the camera calibration report were entered incorrectly or the fiducial mark was collected incorrectly from the scanned image In the Calibration Edge list select the position of the data strip as it appears in the image on the screen Since the camera calibration OrthoEngine User s Guide 25 Chapter 4 Setting Up Camera Calibration and Aerial Photographs normally assumes that the data strip is on the left OrthoEngine compensates for the difference automatically fiducial marks If your scanned image does not include the data strip orient the original diapositive or print to match the image on screen and deduce where the data strip would be on screen 10 When you are satisfied with the results click Accept Once you identify the fiducial marks in your scanned image the parameters from the camera calibration report are used during the bundle adjustment and product generation to compensate for the distortions introduced by the camera See also Collecting Fiducial Marks Automatically on page 26 and Understanding Exterior Orientation Ro step in your project See Understanding Ground Control Points on page 33 Collecting Fiducial Marks Automatically After collecting the fiducial marks manually for one of your images OrthoEngine can use automated pattern matching to automatically collect the fiducial marks for the rest of your images in the proje
271. tereo cursor 3 Position the stereo cursor on a feature When you are satisfied with the x and y positions adjust the z position elevation of the stereo cursor You can also use Snap to Vertex or Snap to Line to position the cursor For more information see Using Snap to Vertex on page 90 and Using Snap to Line on page 90 Beneath the 3 D viewer you can see the x y and z coordinates of the stereo cursor s location 4 Click to select the point Crosshairs indicate the location of the new point 5 Repeat steps 3 and 4 until you have collected the points that you want for the selected layer 6 Click New Point to stop collecting points When you are working with the stereo cursor in the 3 D viewer you can press G to snap the stereo cursor to the ground press P to activate and deactivate New Point For more shortcuts see Using Shortcuts in the 3 D Viewer on page 94 Grex step in your project See Designing the Attribute Table on page 92 Adding Lines to a Layer You should complete the Attribute table each time you add points lines or polygons to the layer For more information about the Attribute table see Designing the Attribute Table on page 92 To add lines to the selected layer 1 Click New Line 88 PCI Geomatics Adding Polygons to a Layer 2 Move the mouse pointer to the 3 D viewer and press ESC to switch to the stereo cursor 3 Position the stereo cursor where you wa
272. the distribution of the ground control points GCPs and tie points for the entire project Images in the project are represented by a frame with crosshairs and ID at the center If information is insufficient to position the images relative to the ground a message will appear in the status bar to indicate that you need to collect more GCPs Table 2 Symbols Item Symbol Selected image red frame Reference image dark blue frame Offline image black frame Other image light blue frame GCP small red square GCP existing on more than one image large dark red square Tie point blue square Tie point existing on more than one image large dark blue square 54 PCI Geomatics Understanding the Bundle Adjustment for Rigorous Math Models To display the overall layout 1 On the OrthoEngine window in the Processing Step list select GCP Collection 2 On the OrthoEngine window click Eel the Display overall image layout icon 3 Under Overview click a crosshair to reveal the image s footprint To open the image double click the image footprint The top of the window points northward If you are not satisfied with the distribution edit your GCPs and tie points Understanding the Bundle Adjustment for Rigorous Math Models The bundle adjustment is simply the computation of a rigorous math model It is a method to calculate the position and orientation of the sensor the a
273. the area to the failed value 4 Select Interpolate and click Apply Under Mask The elevation of the area is interpolated using the values along the edge of the mask 5 Click Clear Mask Neutralizing Cloud Covered Areas When clouds obscure a large area over rugged or mountainous terrain the area may be too complex to interpolate To avoid confounding the data you can set the entire area to the background value To neutralize the effect of cloud cover over rugged terrain 1 Create a mask over the area 2 Type the background value in the Value box beside Fill Using Value 3 Click Fill Using Value This sets the area to the background value 4 Click Clear Mask Dealing with Noise Noise is a random occurrence of irrelevant or miscorrelated values distributed throughout the DEM which reduces its accuracy The following procedure usually produces a satisfactory DEM except for areas containing large bodies of water such as lakes To remove noise from the DEM 1 Make sure all large bodies of water such as lakes have been fixed See Equalizing Pixel Values for Lakes on page 78 2 Select Noise Removal and click Apply to Entire DEM 3 Click Apply to Entire DEM again 4 Select Interpolate and click Apply to Entire DEM 5 Select Smooth and click Apply to Entire DEM 6 Click Apply to Entire DEM again Geocoding a Digital Elevation Model Geocoding means that you are reprojecting the epipolar digital
274. the nominal scale 10 In the Earth Radius box type the earth radius in meters if a notable curvature of the earth is present over the photograph s area 11 Click Accept 24 PCI Geomatics Collecting Fiducial Marks Manually Ho step in your project For the next step in your project see Importing Images or Photographs into Your Project on page 15 Collecting Fiducial Marks Manually OrthoEngine links the fiducial mark coordinates entered from the camera calibration report to the positions that you identify on the scanned image See Entering the Camera Calibration Data on page 24 to enter the position of the fiducial marks from the calibration report You must identify the fiducial marks in every image Images from digital or video cameras do not contain fiducial marks If the image is open click the Collect fiducial info icon on the OrthoEngine window and continue with step 3 2 s Tip If you are working in a project with a large volume of images we recommend that you enter the fiducial marks and ground control points for a limited number of images up to five complete the bundle adjustment for the math model and then check for errors before continuing It is easier to locate bad points on a few images than over the entire project To manually collect fiducial marks 1 On the OrthoEngine window in the Processing Step list select Data Input 2 Openan uncorrected image For more informatio
275. tic Mosaicking 113 Automatically collect GCPs from chip database 44 automatically collect tie point 53 Average 73 Average Filter 106 Average filter 70 Average Image 124 AVHRR intro to OrthoEngine 1 understanding Satellite Orbital Math Model 5 B Background Value 72 75 95 112 113 Backup 127 bad points 57 batch processing DEMs 71 epipolar pairs 71 Baud Rate 46 49 61 BAUD baud rate 61 Bilinear Interpolation 105 black and white bands 43 Blending 117 block averaging 124 Bounds of DEM 67 Brazilian LANDSAT 5 18 breaklines 66 Brightness 116 122 Build Overviews 129 bundle adjustment 55 Bundle Update 36 button characters 60 144 PCI Geomatics C calculation of a rigorous math model 55 calculation of a simple math model 56 Calibration Edge 25 camera calibration data 21 Camera Type 9 Canadian CDs LANDSAT 19 CAP T format 20 CCDs 9 24 CCD arrays 9 CCRS 69 CD Format 16 CD Header Filename 16 CD Image Filename 16 CD read satellite images from 15 CEOS RADAR 16 19 change color of vectors 87 123 change GCP oolor 131 change GCP position on a chip 42 change image color channels 123 change location of GCP on a chip Chip Manager 138 Change Photo Orientation 30 change pixel values 125 change the color of cursor Chip Manager 141 change the color of GCP 43 change the projection for new layer 86 change the size of the chip Chip Manager 138 change the threshold values 132 change tie point color 131 Change to Ch
276. ting Your Images on page 97 To achieve that seamless look in the mosaic place the joints called cutlines where they will be the least noticeable and select images or portions of images that are not radically different in color To begin a Mosaic Only project with a set of existing corrected images see Starting a Project to Mosaic Existing Georeferenced Images on page 12 Figure 9 1 Mosaicking 111 Chapter 9 Mosaicking Your Images Defining a Mosaic Area The Mosaic Area determines the extents of the mosaic file The images are added to the Mosaic Area like pieces of a puzzle On the Define Mosaic Area window the footprints of the images in your project are displayed as they overlap The crosshairs represent the principal point of each image Click one of the crosshairs to reveal the footprint of an individual image You can drag a frame around the area that you want to include in the mosaic or select an existing mosaic file The background value of the Mosaic Area is zero by default For more information about Mosaicking see Understanding Mosaicking on page 111 To drag a frame to define the Mosaic Area 1 On the OrthoEngine window in the Processing Step list select Mosaic nod 2 Click Lj the Define mosaic area icon 3 Onthe Define Mosaic Area window press the SHIFT key and drag a frame over the area that you want To clear the frame click Define New Mosaic Area To change the coordinates under
277. tion Datum essssseseseeeeeenennen nennen nnnm eene en nene enne ener ren esr enrnn innen nennen 128 Changing the Default Orthorectification or Mosaic Output Format nene eene nemen nnnm erret s enne nennen nennen 128 Setting the Channel Type for Your Output Image sssessssseseeeeeeenene eene ennemi nennen Sididae doetiid ener rete rs enn een rn en nennen 129 Understanding When To Build OyernvieWwsS tieien didas 129 Exporting the Math Model ER 129 Exporting the Ground Control Points 5 5 2 t itte Set bh ode gobs dean de REPRE Re oou Dodo u Rie 130 Exporting the Exterior Orientation ene sei eet e ree reda ede ae i heen ah Foe Gee 131 Exporting to Supresoft Format 4 2 Leite ad 131 vii Changing the Default Color Ground Control Points and Tie Points ooooonconnnnccnnnncccnonnnonocannnnnrncnnn nn en eene rra 131 Setting the Threshold Values for the Math Models Bundle Options essen eene nennen enne nennen nere enne 131 Generating a Project Report iii a d dte doe dudes ue ec aaa 132 Saving tlie Project as a Template err m earn 133 Using the File tity c 133 Viewing an Image Outside Your Project moi tii 133 Understanding Format Descriptions for Text Files Containing GOPS esssesssee eene nn nn rn 133 Chapter 11 CREATING A CHIP DATABASE Understanding the C
278. tion type the Coordinate System list For UTM State Plane Coordinate Systems SPCS or Other projection types additional windows may open automatically for you to select the parameters to define the projection or click More to open these windows Select the parameters and click Accept Click Earth Model Click either the Datum or Ellipsoid tab Click a datum or an ellipsoid Click Accept In the list below Coordinate System click Geocoded to enter the map coordinates in georeferenced units or click Geographic to use Longitude Latitude units Select a feature in four corners of the paper map to form a frame surrounding the area where you want to collect the ground control points GCPs Identify the map coordinates of these four features At the end of the Up Left row under Tablet Position click not set On the tablet move the crosshairs of the puck to the feature in the upper left corner of the map and press the button to select the point The tablet coordinates x and y of the point appear under Tablet Position 46 PCI Geomatics Collecting Ground Control Points from a Tablet 18 Type the map coordinates of the point in the Map Eastings box and Map Northings box in the Up Left row 19 Follow the same procedures explained in steps 16 to 18 to collect points for the remaining corners of the map Type the Map Eastings and Map Northings coordinates of the map s upper right corner in the Up Right row th
279. titute Inc Redlands CA 1999 Maling D H Coordinate Systems and Map Projections Pergamon Press Ltd Oxford England 1992 Map Projections Georeferencing Spatial Data Environmental Systems Research Institute Inc Redlands CA 1994 Snyder J P and Philip M Voxland An Album of Map Projections U S Geological Survey Professional Paper 1453 USGS Washington D C 1989 Setting the Projection A projection is a method of portraying all or part of the earth on a flat surface For more information see Understanding Projections and Datums on page 12 The Output Projection defines the final projection for orthoimages mosaics 3 D features and digital elevation models DEMs The GCP Projection is the default used during manual ground control point GCP collection to specify the projection of the collected GCPs or when importing GCPs from text file If you collect GCPs from a geocoded source the coordinates are re projected to the GCP Projection and saved into the project file If you collect GCPs from multiple sources you can change the GCP Projection to match each source using the Set Projection window Using different projections increases processing time during orthorectification It is always more efficient to work with one projection 2 s Tip If you are working on a Mosaic Only project you can click Cancel on the Set Projection window The output projection and resolution will be set automatically from th
280. top bits Check the documentation for the tablet to find which characteristics can be changed and how to interpret the current settings In most cases you can use the default settings with OrthoEngine Configuring the communication depends on the operating system and the tablet used For most systems you must 1 Disable the logins on the port where the tablet is connected 2 Setthe port to match the baud parity data bits and stop bits of the tablet Commands are sent to the tablet for initialization and changing modes The command string consists of a series of characters and special functions Regular text spaces are ignored in the command string which provides some flexibility in creating a legible command string The functions available are PAUSE n Pause for n seconds where n is real For example PAUSE 1 2 will pause for 1 2 seconds ASCII n Send the ASCII character corresponding to the decimal number n VSPACE Insert a space character ISLAS H Insert a back slash character CR Insert a carriage return equivalent to VASCII 13 LF Insert a line feed equivalent to ASCII 10 ESC Insert an escape character equivalent to ASCII 27 If the tablet is not supported by PCI Geomatics you must define the format string A format string is defined using the following characters M Part of button number first button is number 0 N Part of button number first button is number 1 H Hex button number 0 E
281. u are ready to establish a reference frame between the tablet the paper map and your project To set up the reference frame you have to correlate the georeferenced map coordinates of a feature in each of the four corners of the paper map and the x and y coordinates of those features on the tablet After the reference frame is set you can select points on the paper map with the puck The georeferenced coordinates will be transferred to your project for use as GCPs Grid Pinning Since paper maps rarely lie perfectly flat on the tablet s surface you can increase the accuracy in your GCP collection on the paper map by using Grid Pinning to anchor the reference frame around each point that you want to use as a GCP To use Grid Pinning you define the size ofthe frame that you want to use around the point when you set up the tablet When you begin collecting GCP coordinates on the paper map you select a feature and then select the four points to form a square around the feature to anchor the reference frame Anchoring the reference frame around the feature will help eliminate the errors due to distortions in the paper map OrthoEngine User s Guide 45 Chapter 5 Collecting Control Points and Computing the Math Models Ho step in your project See Setting Up the Tablet on page 46 Setting Up the Tablet To set up the tablet you have to establish communication between the tablet and the computer and then establish a refere
282. uide 149 GeoTIFF 128 GeoTiff format 18 Global Positioning Systems See GPS INS 10 GPS INS 10 26 28 See also Photo Scale 23 Grads 28 grayscale bands 43 Grid Pinning 45 ground control point See GCP GTOPO30 DEM 19 guidelines 31 H HDF format 18 header file 16 high residual errors 57 high resolution sensors 10 Highest Score 73 Hold 121 Holes 64 72 80 Hot Spot removal 114 How To Reach Us 4 I Identifying Errors in the Math Model 57 IKONOS converting the DEM datum 126 DEM from stereo pairs 69 intro to OrthoEngine 1 joining tiles 126 minimum number of GCPs 34 setting the GCP elevation datum 128 stitching 126 supported formats 18 understanding Rational Functions Math Model 7 understanding Satellite Orbital Math Model 5 using the right math model 6 Image Format for Radar Enhanced Frost 108 for Radar Enhanced Lee 110 for Radar Gamma Filter 107 for Radar Kuan 109 import Average Image 124 channels 124 digital images 15 exterior orientation 10 28 Format Descriptions 133 GCPs tie points and elevation match points to generate DEM 64 GPS INS 28 Import Exterior Orientation Data from Text File 28 Import GCPs from File 49 Import GPS INS Data from Text File 28 Import GPS INS or exterior orientation data from file 28 layer in 3 D viewer 87 Mosaic Area 112 photographs 15 raster to generate DEM 64 rasters vectors or control points to generate DEM 67 satellite data from PCIDSK 17 satellite images 15 triangulation
283. uidistant from the pixels encoded in the first step In the third step the Finite Difference algorithm iteratively smooths the raster DEM During the iterations the pixels that were encoded in the first step are not changed while the interpolated pixel values are updated based on the neighbourhood values Two parameters determine the completion of the process No of Iterations and Tolerance The No of Iterations parameter specifies the maximum number oftimes smoothing is applied to the raster DEM The default is 10 Tolerance restricts the number of times smoothing is applied according to how it changes the elevation values of the pixels The default is 1 For example you set the No of Iterations to 10 and the Tolerance to 1 meter Smoothing can be applied up to 10 times but smoothing ceases as soon as the smoothing causes a change of less than 1 meter in the elevation values If the maximum change on the third iteration is only 0 3 meters then only three iterations of the smoothing are applied Finite Difference is recommended for files that contain evenly distributed points Since it is a simpler technique it processes the raster DEM much faster and it is better suited to large input data sets 68 PCI Geomatics Building a Digital Elevation Model from a Stereo Pair of Images Building a Digital Elevation Model from a Stereo Pair of Images You can create a digital elevation model DEM from stereo pairs of images whic
284. urther in Understanding the Resampling Options on page 104 under their corresponding method In Filter Size type the number of pixels in width in the X box and the number of pixels in length in the Y box to determine the size of the frame used with the filter In Gaussian SQ box type the first value and in the 2 box type the second value to determine the size of the frame for the Gaussian Filter Click Browse to select the Kernel File 14 Under Processing Start Time click Start Now or Start at hh mm and set the time when you want the operation to begin within the next 24 hours 15 Click Correct Images A progress monitor displays the status of the images being processed Click Cancel if you want to stop the process 2 s Tip If you intend to automatically mosaic the processed images you can click Close instead of Generate Orthos When you set up the Automatic Mosaicking window select Regenerate offline orthos and OrthoEngine will process the images and mosaic them in one step Understanding Sampling Interval The Sampling Interval controls how the computations are performed when an image is orthorectified or geometrically corrected When an image is corrected OrthoEngine selects a pixel from the output file computes the elevation from the DEM if available applies the math model to determine which pixel it corresponds to in the raw image and then transfers the data to the pixel in the output file
285. ute Table on page 92 Adding Polygons to a Layer You should complete the Attribute table each time you add points lines or polygons to the layer For more information about the Attribute table see Designing the Attribute Table on page 92 To add polygons to the selected layer 1 Click New Poly 2 Move the mouse pointer to the 3 D viewer and press ESC to switch to the stereo cursor 3 Position the stereo cursor where you want to begin the polygon When you are satisfied with the x and y positions adjust the z position elevation of the stereo cursor and click to anchor the vertex You can also use Snap to Vertex or Snap to Line to position the cursor For more information see Using Snap to Vertex on page 90 and Using Snap to Line on page 90 Beneath the 3 D viewer you can see the x y and z coordinates of the stereo cursor s location 4 Move the stereo cursor to the next position When you are satisfied with the x and y positions adjust the z position and click to anchor the vertex 5 Repeat step 4 until you have collected the vertices that you need to form the polygon Polygons will automatically close when they are accepted 6 Click Accept or double click when you collect the last vertex to confirm the completion of the polygon and close the shape OrthoEngine User s Guide 89 Chapter 7 Editing Features in 3 D Stereo After the new polygon is accepted it will change from the highlight color
286. vation Scale and Elevation Offset 100 Gaussian function 106 Photo Scale 23 Radar Enhanced Frost 108 Radar Enhanced Lee 110 Radar Gamma Filter 107 Radar Kuan 109 Radial Lens Distortion 22 Erode Holes 78 EROS minimum number of GCPs 34 Errors computed fiducial mark positions 25 26 ERS intro to OrthoEngine 1 minimum number of GCPs 34 supported formats 19 understanding Satellite Orbital Math Model 5 ESA CDs LANDSAT 19 ESC 60 ESRI Shape File 93 estimated error 37 38 40 42 48 50 53 estimated error Chip Manager 138 Example Formats 49 Exclude Min Max 121 export DEM to text file 80 exterior orientation 131 Format Descriptions 133 GCPs 130 math model 129 Project Report 132 Supresoft Format 131 extents of the DEM 73 Exterior Orientation 10 26 29 131 extract DEM from epipolar pairs 71 Extract Elevation 51 Extract from Image File 11 extract the elevation for the GCP Chip Manager 137 Extracted Data table 29 eyestrain 83 F Fiducial marks 23 24 collect automatically 26 collect manually 25 148 PCI Geomatics overwrite 26 File Utility 133 Fill all Failed 76 Fill Failed Cursor 76 Fill Cursor 76 Filter Size for Radar Enhanced Frost 108 for Radar Enhanced Lee 110 for Radar Gamma Filter 107 for Radar Kuan 109 Filters Average filter 106 Bilinear Interpolation 105 Cubic Convolution 105 Erode Holes 78 Gaussian filter 78 106 Interpolate 78 Median filter 78 106 Nearest Neighbor Inter
287. ve a record of all matched chips to a text file 10 Click Close Ho step in your project For projects using the Aerial Photography or Satellite Orbital math models see Collecting Tie Points Manually on page 52 For other projects see Understanding the Solution for Simple Math Models on page 56 Changing the Correlation Parameters for Automatic GCP Collection from a Chip Database The correlation between the chip and the raw image is performed in three progressive levels with each level using a more precise search area Matching begins on a low resolution version of the image to establish an approximate match continues with a medium resolution 44 PCI Geomatics Using a Tablet to Collect Ground Control Points version to refine the match and ends with a full resolution image to produce the most precise match possible Each level produces a correlation score that appears in the Automatic GCP Collection window under Chips in the C1 C2 and C3 columns A high correlation score usually means that the identified matching features are a successful match Scores lower than the Correlation Threshold set in the Advanced Option window are shown in red and are marked as failed However a perfect match may still have a low correlation score since the chip and the raw image may have been taken at slightly different resolutions in different illumination conditions and with different sensors On the contrary repetiti
288. ve features such as lines in a parking lot can produce a perfect correlation score because the features look identical but the match may be on the wrong feature Base your decision to use or reject a match on the correlation scores instead of whether the matching is marked passed or failed To change the defaults for the minimum correlation score required for each level 1 Inthe Automatic GCP Collection window click Advanced Options 2 Inthe Advanced Option window under Correlation Threshold type a value between zero and one for each of the levels 3 Click OK To change the size of the search area 1 Inthe Automatic GCP Collection window click Advanced Options 2 Inthe Advanced Option window under Correlation Mask Window size type the number of pixels to form the width of the search area for each level The search area is an odd number of pixels forming a square The last level using the full resolution version of the image always uses a search area that is 7 by 7 pixels large 3 Click OK Using a Tablet to Collect Ground Control Points By using a digitizing table connected to your computer you can transfer the coordinates of a feature from a paper map to your project and use the coordinates as a ground control point GCP A digitizing table consists of a electronic platform a tablet and a pointing device a puck After you connect the digitizing table to your computer and tape the map to the tablet yo
289. ve project as template 133 scale 23 Score Channel 72 73 Search Criteria 41 43 search for chips 42 Search image chips Chip Manager 139 search the chip database Chip Manager 139 select a 3 D stereo pair 84 select a GCP on a tablet 48 selected channels 16 Set Camera Calibration 24 set default units for datum 128 Set GCP Projection based on Output Projection 14 Set of DEMs to Merge 64 Set of Vector Layers to Interpolate 66 Set Trim 121 set up tablet 46 setting GCP elevation units 127 shadows 52 Shapes See masks Shortcuts for the 3 D viewer 94 Show Distribution 44 Show Image or DEM 75 Show Mask 76 shutter glasses advantages and disadvantages 82 simple math models 56 geometric correction 101 SIN 8 Pt and 16 Pt SinX X 105 Size of DEM 67 size of DEM pixel 74 size of the chip 137 138 OrthoEngine User s Guide 155 size of the search area 45 SLASH 60 Smooth filter 78 Snap to Line 90 Snap to Vertex 90 solution for rigorous math models 55 source image for chip 136 SPACE 60 SPOT DEM from stereo pairs 69 intro to OrthoEngine 1 joining tiles 126 minimum number of GCPs 34 stitching 126 supported formats 19 understanding Satellite Orbital Math Model 5 SPOTIMAGE SPOT 19 square sensor cells 24 Standard Aerial Camera 9 Start Aerial Photography project 9 OrthoEngine 9 Polynomial project 11 project to mosaic existing orthos 12 Rational Functions project 11 Satellite Orbital project 10 Thin Plate Spline project 12 unde
290. viewer and the pointer is 84 PCI Geomatics Adjusting the Alignment in the Stereo Viewer activated When the pointer returns to the viewer the stereo cursor resumes control and the pointer disappears However if you want the stereo cursor to remain on a specific point in the viewer while you move to select a tool you must switch from the stereo cursor to the pointer without moving the mouse To switch between the pointer and the stereo cursor 1 Move the pointer to the viewer and press ESC The pointer disappears and the stereo cursor is activated 2 Move the stereo cursor to a feature in the image and press ESC The stereo cursor remains on the feature and the pointer reappears Moving the Stereo Cursor Pixel by Pixel Press the keyboard arrow keys to move the stereo cursor screen pixel by screen pixel Press CTRL the ARROW keys to move the stereo cursor 10 screen pixels at a time Moving the Stereo Cursor to Different Elevations By adjusting the difference in x coordinate or parallax between the left and right cursors you control the apparent height of the cursor This way you can position the cursor not only in x and y but also in z To change the elevation of the stereo cursor Rotate the wheel button Press Z to move the stereo cursor to higher elevations and press X to move the stereo cursor to lower elevations Press G to snap to ground which means to automatically move the stereo
291. wer and upper limits of the range 4 ClickSave Working LUT for Mosaic Areas using 8 bit channels or Save Working State to save the lookup table with the image Quote If you reopen Color Balancing the lookup table saved with the image is not shown automatically Click Show Saved LUT for Mosaic Areas using 8 bit channels or Show Saved State to display the lookup table and the match areas that were saved with the image The saved lookup table cannot be edited If you select new match areas and click Save Working LUT or Save Working State the previous lookup table is replaced Ro step in your project Continue with steps in Adding the Image to the Mosaic Area on page 116 Adding the Image to the Mosaic Area Continuing the steps from Adjusting the Color Balance on page 116 1 Under Mosaicking Steps click Add Image to Mosaic 2 Click Add Image to Mosaic File to complete the mosaicking process The selected portion of the image is added to the Mosaic Area 3 Return to step 3 of Adding an Image to the Mosaic on page 115 and repeat the steps for each image you want in the mosaic 116 PCI Geomatics Understanding Cutlines Blending the Seams Blending reduces the appearance of seams by mixing the pixels values on either side of the cutline to achieve a gradual transition between the images In Automatic Mosaicking OrthoEngine blends the seams automatically In Manual Mosaicking the Blend Width
292. y orthorectify the images If OrthoEngine does not generate the orthorectified image The image to be processed is not accessible offline The image is not from the demo data sets and you are working in demo mode unlicensed The DEM file is not accessible offline The filename of the orthorectified image is missing The math model is not computed The orthorectified image already exists but its georeferencing or resolution is incorrect Understanding the Resampling Options Resampling extracts and interpolates the gray levels from the original pixel locations to corrected locations These methods are available Nearest Nearest Neighbor Interpolation on page 105 Bilinear Bilinear Interpolation on page 105 Cubic Cubic Convolution on page 105 Sin 8 Pt and 16 Pt SinX X on page 105 Average Filter on page 106 Median Filter on page 106 Gaussian Filter on page 106 User Defined Filter on page 106 The following filters are only available for radar images Radar Gamma Filter on page 107 Radar Enhanced Frost Filter on page 108 Radar Kuan Filter on page 109 Radar Enhanced Lee Filter on page 110 wee Reference The implementation of the speckle filters were based on the following papers and especially the review paper by Shi and Fung 104 PCI Geomatics Understanding the Resampling Options Jong Sen Lee Di
293. ze in the units meters feet or degrees used in the project In the Fill Holes list select Yes if you want to enhance the output quality of the DEM by interpolating the failed values automatically Select No to set all the failed pixels to the background value in the output DEM Click Geocode DEM Exporting a Digital Elevation Model to a Text File You can export the digital elevation model DEM into a text file The file will contain the x and y coordinates and the gray levels representing the elevation values To export the DEM to a text file l 10 11 On the OrthoEngine window in the Processing Step list select DEM From Stereo Click ae the Export the Geocoded DEM to text file icon Under Input DEM in the File box type the path where the DEM is found or click Browse to select the file In the DEM Channel list click the DEM channel or click Select to view the choices and choose a channel In the Failure Value box type the value used to represent the failed pixels in the input DEM In the Background Value box type the value used to represent the background Under Input Window click Full Image to export the entire DEM Window to export a specific area of the DEM In the Offset boxes type the pixel and line coordinates of the upper left corner of the area In the Size boxes type the number of pixels and lines to specify its size In the Spacing box type the sampling frequency of the pixels expo

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