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Geodesic Photogrammetry System

1. 1 GPS file buttons Consist of two options New for creating a new GPS file Close for closing the new GPS file 62 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 5 Startup and Menus 2 Net Size pop up menu Allows you to indicate the model of the GSN worn by the subject 3 Number of Sensors indicator Lists the number of sensors in the GSN model chosen in the Net Size pop up menu 2 4 Pedestal Height indicator Shows the standard pedestal height in millimeters for the sensors in the GSN model chosen in the Net Size pop up menu 2 To view the variant pedestal heights for the GSN model choose View gt Info Window gt General which is described in Info Window on page 67 Note To create variant pedestal heights that are not included in the standard GSN models contact support egi com 5 GPS Number indicator Shows the unique identifying number for the GPS 6 Assign Subject button visible if no subject is assigned to the file Opens the Select Subject window where you can assign a subject to the GPS file Figure 5 3 Select Subject Enter Subject Identifier or Select From Table Cancel E select Figure 5 3 Select Subject window The resulting GPS solution set is then saved to that subject and is used to provide 3D information for other Net Station tools Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November
2. The Tools menu Figure 5 16 offers advanced features for processing data The most important for this application is Photogrammetry ETE The appearance may vary depending on your Waveform Tools 3T Net Station license Photogrammetry Jobs and Results 3J Browse Event Criteria Browse Files 8 Browse Subjects Figure 5 16 Tools menu e Photogrammetry opens the Photogrammetry dialog 72 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 5 Startup and Menus Opening a GPS File You can open a GPS file using various methods many of which are familiar to Macintosh users e Open Net Station choose File gt Open or press Command O and navigate to the file e Open Net Station click the Select button and navigate to the file e Double click on the GPS file icon see Figure 5 17 which also opens Net Station if closed PHOTOGRAMMETRY e If you have just acquired images and want to immediately open the GPS file click the Open Figure 5 17 GPS file icon Dataset button in the Photogrammetry dialog Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 73 5 Startup and Menus 74 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 6 CAMERA CALIBRATION O nce the hardware and software are installed the first task is to calibrate the cameras After the system is calibrated it c
3. ine e e l N N Y 1m A W M 1 NN NM NM ww 1 ww eS OS ee e e se 7 8 Coordinate 12 046 8 243 1 526 5 12 997 7 665 2 028 13 070 6 203 3 979 11 663 4 404 6 893 9 174 3 001 10 909 2 864 1 055 11 520 334 wom mir Figure 8 21 Sensor Locations window The following are brief descriptions of the numbered items from Figure 8 21 1 Number column Indicates the sensor s actual GSN ID number determined through triangulation and scaling of the corresponding EGI Head Model 2 Cameras column Lists the camera views where the sensors are marked The software displays the camera numbers within parentheses if it considers a point questionable the software substitutes a point from the EGI Head Model for the questionable point Questionable means that the software is estimating the sensor location and number to verify apply the camera overlays and refer to the corresponding sensor layout 3 Solved column Indicates whether the software considers the sensor s location and ID solved In the images solved points are in bright green unsolved points in khaki green and questionable points in pink 4 RMS column Indicates the root mean square error of the coordinates of the solved sensor location measured in units of millimeters The error represents the difference between the solved 3D points that the software overlays on the images the 3D Point Clo
4. Export Instructions 1 Inthe Model window click the 1 Up button 2 Click either the Lpa or Rpa button and mark the corresponding preauricular point in the image a yellow LPA or RPA label appears at each mark 3 Cycle through the images marking this point where it appears 4 Repeat Steps 2 3 for the other preauricular point 5 Click the Update Model button Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 13 9 Data Export 6 Choose File gt Export and select the export format output file name and output destination see Figure 9 3 Export Export Photogrammetry File To Coordinate File Save As HeatherCompletelysolved sfp Format Besa SFP file Es Where T Photogrammetry files HA fa m otog PT fm qooadtc carc SAn 000o care otog Ol backup fm goodtc Caras otogTOC fm goodtom_markedall New Folder Add to Favorites feel Figure 9 3 The Export dialog Note If you receive an error message see Photogrammetry Error Messages on page 156 Examples of exported files are shown in Figure 9 4 2 Heather1111_besa sfp idNz 8 88808 10 52575 4 24999 FidT 7 69364 7 16558 7 46052 0 f Probe file FidTia 7 72187 7 83318 7 57376 fAMinor revision number E1 5 87618 6 99531 2 72972 1 EZ 5 39526 5 73877 0 09077 ProbeName E3 4 21253 4 81765 2 45166 a Name E4 2 47170 2 96277 5 83425 Probe typ
5. comparison w SEDET BB veatnercomostetrstendi miber a Figure 5 11 View gt Compare Nets Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 69 5 Startup and Menus Actions Menu The Actions menu items are identical to the Identify Sensors Update Model and Calibrate buttons displayed in the Model window during system calibration or sensor modeling Figure 5 12 shows the menu Actions iil Identify Update Figure 5 12 Actions menu e Identify identical to clicking the Identify Sensors button see 2 Identify Sensors button on page 122 e Update identical to clicking the Update Model button see 3 Update Model button on page 122 e Calibrate identical to clicking the Calibrate button see Step 8 on page 83 and read Chapter 6 Camera Calibration for a discussion of the calibration process Net Station Menu The Net Station menu Figure 5 13 contains standard commands for operating Net Station For a full description of all the menu commands see Chapter 4 Menus of the Net Station Viewer Technical Manual Net Station 4 2 About Net Station Preferences a6 Services b Hide Net Station 4 2 H Hide Others XH Cie A 7 WAY O SI I ah j 1 Quit Net Station 4 2 AQ Figure 5 13 Net Station menu 70 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 5 Startup and Menus File Menu Th
6. thereafter will require that you click the Update Model button unless you wish the software to renumber or recalculate the solution set In that case you will click the Identify Sensors button Figure 8 1 shows a flowchart of the marking process and Figure 8 2 shows a flowchart of the editing process The sections that follow these flowcharts provide additional information about these procedures Acquire images following the steps in Figure 7 1 on page 96 No Do you have B MS Yes Open the GPS file gt In the Model window click the agen 1 Up button Using the sensor layout as a gt guide mark the cardinal points visible in the camera view Click a Navigation forward button to T Do you want view another image to change a point After marking the cardinal sensors in all 11 images save a copy of the marked up file In the original file To delete a point press the Shift key and roll over the point with Are you the cursor When the delete satisfied with symbol appears click the points click the Identify Sensors button which signals the GPS to use triangulation to solve for the points To move a point roll over the point with the cursor When the move symbol appears drag the point to the new location To undo a deletion or a move press CommandZ Figure 8 1 Sensor marking Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22
7. Calibration Object Precisely manufactured sohere measuring 10 91 cm 9 in in radius 34 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Table 2 4 GPS hardware Calibration stand Manfrotto 3001 BD tripod stand 2 3 8 16 x 2 1 2 bolts 2 3 8 16 hex nuts Materials to connect 4 3 8 flat washers gantry s rolling base to main body 4 1 4 20 x 3 4 bolts 2 1 4 20 hex nuts 4 1 4 flat washers Assembly requires 1 9 16 end wrench 1 9 16 socket wrench 1 7 16 end wrench and 1 7 16 socket wrench which are not provided ee ee eee eee Materials to connect 2 1 4 20 x 3 bolts dome to gantry s dome 4 1 4 20 x 2 bolts 6 3 8 acorn nuts 3 pipe clamps support 6 3 8 flat washers shims Assembly requires 1 3 8 end wrench and 1 3 8 socket wrench which are not provided Assembly Instructions The geodesic dome and gantry are packaged in two separate crates Bolts washers nuts and clamps are loosely attached to their intended locations on the equipment A Caution Assembly requires two people because of the GPS size and weight Gantry Overview The gantry consists of the rolling base and the main body Assembly entails securing the main body to the rolling base The main body contains a dome support see Figure 2 3 that is designed to hold the GPS dome In addition a motorized control on
8. Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 129 8 Sensor Modeling Model View Controls The model view controls allow you to manipulate the model You can view it from different perspectives zoom in or out rotate or move the model or change viewing preferences such as background color e Perspectives click this button to open a pop up menu that allows you to choose different perspective from which to view the model Perspectives e Zoom click this button and drag the cursor toward or away from the center of the model to zoom in or out 4 e Rotate click this button and drag the model to rotate This allows you to examine the model from any angle Zoom e Move click this button and drag the model in any direction e Filters click this button to open a pop up menu allowing you to choose from various drawing tools Rotate o Renderer Quesa Wireframe or Quesa Interactive for a wire based or a solid based representation Wireframe graphics display much faster than ty interactive graphics Brightness changes brightness on a 10 point scale with 6 as normal O Move Background color allows selection of color O j Remove backfaces allows you to view only the front plane not the back Ses plane of an object speeds up the display Filters O Phong shading interpolates colors across an image for a realistic 3D effect requires additional d
9. Overview of marking and editing cardinal points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling dite 1 Using the GSN s sensor layout as a guide mark the cardinal points in camera view 1 the average number of cardinal points visible in each camera view is 3 For more guidance on marking cardinal points see Tips on Marking the Cardinal Points on page 114 With the Onion Skin filter applied we can see that 3 cardinal points have been marked Arbitrary numbers are assigned to them until the Identify Sensors button is clicked which triggers the cross correlation and numbering process Tie Loe 2 Proceed to camera view 2 and mark the visible cardinal points The Onion Skin filter shows that 3 cardinal points have been marked ee Pe 3 Continue marking the cardinal points in each camera view when done save a copy of the marked up file In the original file click the Identify Sensors button See Saving File Copies on page 109 The Onion Skin filter shows that only 1 cardinal point has been marked Depending on camera angles and head shape some camera views may display only 1 cardinal point and others may show as many as 4 Figure 8 4 Expanded view of Steps 1 3 in marking and editing cardinal points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 111 8 Sensor Modeling 4 Ifan error
10. Refer all servicing to EGI or other qualified personnel e Disconnect power before servicing to prevent damage or injury e Ensure grounding reliability This can be achieved only when equipment is connected to an equivalent receptacle marked Hospital Only or Hospital Grade e Use a properly grounded outlet Otherwise damage or injury may result Cords Connectors and Cables Following are WARNINGs regarding the GPS s cords connectors and cables e Use approved power cords Do not use any power cord with the GPS that is not approved in the country where the system is being used In the United States and Canada a hospital grade plug cord set must be used e Inspect your connectors and cables To reduce the risk of electrical shock discontinue use of worn or damaged electrical connectors and cables 54 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 o Disassembly O Following are WARNINGs regarding disassembly of the GPS Do not open and try to fix the GPS The interior of the GPS contains no user serviceable parts In the event that the GPS requires servicing contact EGI Technical Support Appendix A e Do not touch the power supply The gantry body houses the power supply Touching any internal portion of the power supply while the GPS is powered could result in electrical shock or electrocution e Do not open the GPS when in use Open the GPS gantry body only
11. from moving parts and use caution when operating lo prevent injury Do not immerse of splash electrical equipment as damage of injury may reaut Nol for use in flammable gas arvironmants Moving parts warnings for text see General Satety Warnings on page 53 General safety warnings for text see General Satety Warnings on page 53 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 33 2 Hardware Assembly Overall System Dome and Ganiry The main components of the Geodesic Photogrammetry System are the geodesic dome and the gantry which are shipped in two separate crates Assembly of the main system components is discussed later in this chapter Assembled the system measures 150 x 102 x 221 cm 1x w x h and weighs 77 kg see Figure 2 2 weight 77 kg O O BY O De length 150 cm width 102 cm height 221 cm Figure 2 2 Weight length width and height of assembled system Table 2 4 lists all the hardware components that come in the two crates for assembling the complete GPS Table 2 4 GPS hardware Component Description Dome Icosahedral aluminum structure measuring 102 x 102 x 89 cm or 40 x 40 x 35 in I x wx h Gantry main body Steel support structure measuring 57 2 x 34 6 x 130 2 cm or 2 5 x 13 6 x 51 3 in Ix wx h Gantry rolling base Steel mobile base measuring 110 5 x 84 x 15 cm or 43 5 x 33 x 6 in I x wx h
12. 1 4 20 bolt dome support Rolling base bottom view Main body side view Main body bottom view Figure 2 6 Rolling base and main body connection points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 39 2 Hardware Assembly 1 Lay the main body on its back 2 Remove the tape from the bottom ends of the internal straps Position the rolling base and the main body lining up the six bolt holes and fitting the Remove the six bolts and small lip on the base their washers and nuts inside the main body from the rolling base Have a colleague hold the rolling base in place 6 Attach the straps to the base with the 1 2 20 x 3 4 bolts and washers See Figure 2 8 Hand tighten only Attach the gantry to the rolling base at the Using the wrenches tighten all six bolt sets bottom using the 3 8 16 bolts washers and With one person on each side of the assembled nuts and at the front gantry set it upright carefully using the 1 4 20 bolts washers and nuts See Figure 2 8 Hand tighten only Figure 2 7 Gantry assembly process 40 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Bottom bolt 3 8 16 x 2 1 2 bolt 3 8 16 washer Main body Rolling base 3 8 16 washer 3 8 16 nut y Bottom of gantry Front bolt 1 4 20 Main body washer 1 4 20 washer 1 4 20 Front bolt a 1
13. 1 860 calibration obj noe Ose Gna AMOO wie clicking ina i 1 2 4 5 6 1673 i470 2 226 isu i 30 DEPT row displays 3 12 3 8 imna sui ihe 3 Up 4 1 3 4 5 5 1612 6469 ae window with J T 55 isu ne the model 2 7 11 1633 9 6604 5 7 4 9 osio 146 number 3 4 5 9 se 0 416 4 077 r 10 5 6 10 a 1 528 087 highlighted lt neo 12 1 2 3 6 J 1 116 7 129 3 123 4 0707 307 l 1 3 4 5 1000 aaj is 1 4 5 6 2 1658 2 967 16 1 2 5 6 os 3 353 17 12 3 7 1323 asis 18 13 48 1 500 1 54f 19 1 4 5 gt 1291 7650 20 1 5 6 10 1000 osai 21 1 2 6 11 1225 ang 22 2 37 11 1000 12 044 23 2 3 7 1528 794 24 3 4 7 8 e tiis 13654 25 3 4 8 9 1732 s 00g 26 4 5 8 9 1225 sso 27 4 5 9 10 1000 s 012 28 5 6 10 1732 4 189 29 5 6 10 11 e 1658 2061 30 2 6 10 11 i72 8384 a FET a an as E Select Cardinal Points Version 1 0a6 i Figure 8 22 The selected sensor number in the 3 Up Model window and the model view Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 135 8 Sensor Modeling 136 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 9 DATA EXPORT T he final routine step is exporting the data to text files in either BESA SFP or EMSE Elp file formats The process involves marking fiducial points triangulating their 3D positions and choosing File gt Export After export these points serv
14. 145 chapter 12 GPS FAQs 147 General Issues 148 Acquiring the Images 150 Marking the Points 151 Modeling the Points 152 Photogrammetry Error Messages 156 Appendix A Technical Support 159 Before Contacting EGI 159 Contacting EGI 159 Appendix B Updating EGI Licenses 161 Tips on Updating EGI Licenses 162 Opening the Updater Application 163 Generating the Update File 164 Applying an Updated File 165 Questions 166 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 yii Contents Appendix C EMC Declarations for GPS 167 Appendix D Calibration Target Layouts 173 Appendix E Sensor Layouts 179 Glossary 187 Index 191 vill Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 LIST OF FIGURES Preface P 1 Image acquisition and sensor modeling xvii chapter 1 System Overview 1 1 A top view of the dome and its 11 cameras left and attached to the gantry right 24 1 2 GPS operational overview 28 chapter 2 Hardware Assembly 2 1 The GPS dome and gantry assembled 31 2 2 Weight length width and height of assembled system 34 2 3 The gantry s main body straps attached to body s interior and rolling base 36 2 4 Dimensions of the assembled rolling gantry front left and side view right 36 2 5 Another view of the positions of the front bottom and strap bolts 37 2 6 Rolling base
15. 2006 107 8 Sensor Modeling This means that some points are misnumbered marked in only one camera marked in too many Did you receive cameras etc In both cardinal and non cardinal a message about an Yes J gt mode you must correctly identify the points once incorrect number of points View each image and make sure that each sensor is o correctly marked edit the marks using the sensor layout for guidance as needed In the Sensor Locations window mark these points as solved Choose View gt Sensor Locations to find the unsolved points Double Click the Identify Sensors button to identify the click on a point to view it in points correctly its camera views Edit the point renumber move add or delete a mark in the camera views manually mark the point as solved in the Sensor Locations window and click Update Model Repeat until all points are solved save a copy of the solved file Do you want to export your data Yes _ gt Follow the instructions in Chapter 9 Data Export No Do you want to mark all remaining sensors Using the original file follow the instructions in Figure 8 1 on page 107 except mark the other sensors NOT the cardinals Figure 8 2 Editing points 108 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling Saving File Copies It
16. 22 2006 75 6 Camera Calibration 36 numbered circles spaced evenly over the object that you mark and number from within Net Station Photogrammetry Figure 6 1 Targets 1 11 are the camera targets They should point to their respective cameras in the GPS dome Figure 6 1 The GPS Calibration Object separate from its stand left and outside the dome right The calibration procedure involves optimizing the camera parameters so as to place all the calibration targets on a spherical surface of the correct radius while maintaining high convergence between the lines from the image planes to the surface The Calibration Object and stand are shipped unassembled Simply mount the Calibration Object onto the adjustable stand to assemble and position it within the dome Calibration Overview The process of calibrating your system is nearly identical to regular GPS operations except you must manually number the calibration targets e position the Calibration Object within the dome e acquire images using the Acquisition window e open the GPS file and e mark manually number and model the points in the Model window 76 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 Camera Calibration This chapter does not discuss the Acquisition and Model windows detailed descriptions of those windows are provided in Chapter 7 Image Acquisition and Chapter 8 Sensor Modeling
17. 3 numerical order or through camera Figure 7 4 Navigation tool triads 5 Camera pop up menu Displays the current camera and allows manual selection of another camera 1 through 11 This menu is visible in 1 Up and 3 Up Acquisition and Model windows it is not visible in any All Up modes 6 Camera view Streams video from the current camera until the Take Pictures button is clicked The camera view then shows the captured stills for the camera The images are not clickable or editable All Up Window The All Up window contains 11 thumbnails representing 11 different perspectives The camera views are arranged in the same pattern as the cameras in the GPS dome Double click in any of the camera views to display that selected image in the 1 Up mode The All Up window is useful for determining whether the subject is positioned well in all camera views during image acquisition The All Up window contains few buttons and options Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 101 7 Image Acquisition Figure 7 5 shows the All Up Acquisition window 00 Heathertiti gt l real zra 2 en Click the 5 All Up button rightmost to view all 11 thumbnails The camera views are in the same positions as the cameras in the GPS camera structure Version 1 0b4 Figure 7 5 All Up Acquisition window The following are references for or brief descriptions of the numbered item
18. 3 Click the Numbers button which enhances the visibility of the User marks Sobeet Pista tir Cikini tee Figure 6 8 Expanded view of Steps 1 3 in marking the calibration targets 84 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Geodesic Photogrammetry System Technical Manual Change Number f Cancel o ee ee Cal irhip Select Pinta foe Cabin atos 6 Camera Calibration 4 Inthe camera view double click on the dot in the middle of the calibration target to open the Change Number dialog 5 In the Change Number dialog type in the correct number and click Change Note An alternate way to number the calibration targets is to use the Number labeler see 7 Number labeler on page 125 6a Ifthe mark is precisely positioned and numbered correctly repeat the process for the other targets in the camera view and click Save Figure 6 9 Expanded view of Steps 4 6a in marking the calibration targets S MAN 200 GPSR 001 November 22 2006 85 6 Camera Calibration Bop Cal Barhip E Ra omi MOO wiel 4 Cikti Sabet Poanta tir Cilin afer rd Click the camera pee gt in the dome aaa Camera 7 l VAN T Camera amp 1 ve Campra 9 Camera 10 Camera 11 Click the forward button the pop up menu 0 0p Caliiship E oe RA omi MOO hiel i debe ale i Taieri Poenta tir Cilin airan Choose the camera from 6b If
19. Compare Nets All fiducials must be marked You are trying to compare Net data that and solved in order to use the lack marked and solved fiducial points Compare Nets function Click a fiducial button and mark the corresponding fiducial in at least two camera views Do this for the other fiducial points Compare Nets Unable to compare nets of You are trying to compare sensor different types registration data obtained with different Net models 64 channel GSN 200 adult and 128 channel HydroCel GSN adult for example Reselect the comparison GPS file and make sure it is based on the same Net model as the current GPS file 158 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Geodesic Photogrammetry System Technical Manual appendix A TECHNICAL SUPPORT Before Contacting EGI Please check the Contents on page v and the Index on 191 for coverage of your issue or question You can also perform an electronic search using Find or Search in the PDF version of this manual posted on the Documents page of the EGI website www egi com documentation html In addition the Support page of the EGI website www egi com support html may have the information you need If you need more help EGI recommends the following e Try to isolate the problem Is your problem well defined and repeatable e Document the problem Carefully record and organize the details gleaned from
20. Locations To open choose Views gt Cameras Solved RMS Coordinate Sensor Locations _ Rie Pri 3 109 12 046 8 243 1 526 2 2 3 7 4546 12 997 7 665 2 028 3 1 2 3 7 4 822 13 070 6 203 5 979 calibration target 4 1 2 3 6 403 11 663 4 404 8 893 number 5 1 2 3 4435 9 174 3 001 10 909 4 6 1 2 6 5 598 5 864 1 055 11 520 Delete Mark Solvec Figure 6 14 Sensor Locations window Unlike the system RMS value the RMS value in the Sensor Locations window is calculated in 2D space and measured in units of pixels As a general guideline if all the relevant points in the Sensor Locations window have RMS values of less than 3 pixels the system will successfully calibrate producing a system RMS of less than or equal to 2 centimeters Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 89 90 6 Camera Calibration To improve RMS values using the Sensor Locations window 1 Click on the RMS column to sort the calibration targets by RMS value 2 Locate calibration targets with high individual RMS values in general greater than 3 For a high RMS calibration target double click on its number in the Number column to open a 3 Up window of the calibration target which is circled in the camera Views Move add or delete User marks using as viewing aids the camera filters and overlays which are discussed in Chapter 8 Sensor Modeling Some tips for lowering high
21. Number column Indicates the point s arbitrary number Click on the column header to sort the data by point number 3 Model Number column Indicates the point s actual GSN ID number determined through triangulation and scaling of the corresponding EGI Head Model Click on the column header to sort the data by model number 4 Solved column Indicates whether the software has solved the point s location and true ID number Click on the column header to sort the data by solved status 5 Sorting toggle Allows you to sort the columns in ascending up arrow or descending down arrow order 6 Delete button Allows you to delete a row by selecting the row and clicking this button 7 Clear Mark Solved button Allows you to designate a model number as solved or unsolved by selecting an item in a row and clicking this button the model number s solved unsolved status propagates throughout the window The status of the button depends on the row selected If an unsolved row is selected the Mark Solved button appears If a solved row is selected the Clear Solved button appears If no row is selected neither button is available Note An alternative to the Clear Solved button is clicking a green circle in the Solved column all instances of that model number are automatically cleared of their solved status in the Observations window 132 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8
22. Object for image acquisition 79 Expanded view of Steps 4 6 in positioning the Calibration Object for image acquisition 80 Expanded view of Steps 7 9 in positioning the Calibration Object for image acquisition 81 Marking the calibration targets 83 Expanded view of Steps 1 3 in marking the calibration targets 84 Expanded view of Steps 4 6a in marking the calibration targets 85 Expanded view of Steps 6b 8 in marking the calibration targets 86 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 List of Figures 6 11 Unable to acquire images 87 6 12 Retry window 88 6 13 The default Acquisition window 88 6 14 Sensor Locations window 89 6 15 Calibration pane 91 6 16 File selection dialog 92 chapter 7 Image Acquisition 7 1 Acquisition process 96 7 2 3 Up All Up and 1 Up Acquisition windows 99 7 3 3 Up Acquisition window 100 7 4 Navigation tool 101 7 5 All Up Acquisition window 102 7 6 1 Up Acquisition window 103 chapter 8 Sensor Modeling 8 1 Sensor marking 107 8 2 Editing points 108 8 3 Overview of marking and editing cardinal points 110 8 4 Expanded view of Steps 1 3 in marking and editing cardinal points 111 8 5 Expanded view of Steps 4 6 in marking and editing cardinal points 112 8 6 Expanded view of Steps 7 9 in marking and editing cardinal points 113 8 7 Point status by dot or parentheses in the Sensor Locations window 115 8 8 Sensor status by color in the Model window 115 8
23. RMS values O In most cases if more than three cameras are listed in the Cameras column you can improve the RMS value by deleting one of the marks If only one camera is listed in the Cameras column then view the calibration target in the 3 Up window and mark it in one more camera view even if it is obliquely visible See Appendix D Calibration Target Layouts for the calibration target numbers If three cameras are listed in the Cameras column then view the calibration target in the 3 Up window and move the marks until they appear more precisely placed If this fails you may need to delete a mark in one camera view and mark the calibration target in another camera view for better line of sight Click the Update Model button in the Model window to recalculate the individual RMS values Progress through the Sensor Locations window until no target has an RMS value greater than 3 Click the Calibrate button If no RMS error is high message appears the system is correctly calibrated and you can continue to Chapter 7 Image Acquisition if the RMS error is high error message appears repeat Steps 1 7 until the system is successfully calibrated Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 Camera Calibration To enhance the visibility of the User marks and calibration targets you can apply a camera filter or overlay to the camera views for more informatio
24. Station The name of the HASP key is in the bottom left of the Net Station start up eens screen Quit Net Station launch the Updater application and apply the corresponding HASP file File organization Avoid duplicate Update files After emailing your Update file to EGI delete it from your computer Likewise after applying the Updated tile from EGI to your HASP key delete the file Figure B 2 HASP updating tips 162 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 B Updating EGI Licenses Opening the Updater Application 1 Quit Net Station if necessary 2 Insert the HASP key into the USB port at the side of your keyboard or at the back of your computer A light should illuminate within the key e808 Z Data Acquisition O oo mm m A Forward View Computer 12 items 126 1 MB available Date Modified _ Today b gt E Applications Mac OS 9 Today 3 On your hard drive open the Applications folder gt Desktop 11 4 02 k Desktop Mac OS 9 11 4 02 ko Documents Yesterday pa gt Library 1 15 03 808 A Applications 0 gt Punward or 4 Open the Net Station install f f Name Date Modified 35 items 126 MB available folder in the Applications folder gt i xplorer 5 7 10 03 r gt L Net Station 8 770 gt Retrospect Client 11 4 02 gt 9 SM
25. Technical Manual describes all hardware components and features of the Geodesic EEG Systems Software related e The Net Station Acquisition is the component of Net Station for acquiring EEG in conjunction with Geodesic Sensor Nets The Net Station Acquisition Technical Manual describes all Acquisition features and functions The Net Station Viewer is the component of Net Station for viewing and navigating EEG data The Net Station Viewer Technical Manual describes all Viewer features and functions Geodesic Photogrammetry System Technical Manual The GPS works with the GSN and Net Station Following are brief descriptions of these and other related EGI products The manuals are available as PDF files at www egi com documentation html S MAN 200 GPSR 001 e November 22 2006 Preface e The Net Station Waveform Tools is the component of Net Station for performing various operations on EEG data The Net Station Waveform Tools Technical Manual describes all Waveform Tools features and functions e The Net Station Viewer and Waveform Tools Tutorial instructs you in the use of Net Station Viewer and Waveform Tools by guiding you through the analysis of a sample data set It is not intended to be a comprehensive guide to these components but it is a good place to start when learning about the software e The Net Station File Formats Technical Manual documents the objects contained in a native Net Station file the form
26. a a bicolor model in the model view showing the current file s points in green and the comparison file s points in blue b the difference between each model point in the Difference window in centimeters and c the average RMS error in centimeters Figure 10 2 eee Met Comparise fH t ie Fig LALELE ied Pe amita i ther w a rok Geodesic emor Met 128 2 1 t TEE J Oa 2 Guna E O4515 ry edhe EEA i g LHT 2 eo ee Lil sari 1 osg18 1 THN p E g gt e 6 13 PETET Otis 15 GHAI ia om Ld 16 Lae Li OA r z Ge a 15 aao t arara ae j PETET i TIET 5 u a my O08 G m PETET B JEH 6 Pa LS e oda rk 28 Gaya z9 ETSY i a0 PERITI eS 71 aT a a2 Ores aa rE EFT Fa FS Fe tg gt 16 diedi ww te 2 w iF PEES T HeathenCergdershasived2 HeatherCommsleneha ved RAS Ferra ORERE Figure 10 2 Example results from comparing the sensor registrations of a GSN pre and post exam 144 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 11 PRINTING GPS IMAGES AS mentioned in File Menu on page 72 the Photogrammetry software offers no printing option You can however take screen shots of the windows or create TIFF images of the contents of selected views and print from those programs Screen Shots For screen shots press Command Shift 4 for a user selectable image or Command Shift 3 for the entire screen Open the
27. accurately registered in the images The Photogrammetry software assumes that all the sensors are perpendicular to the scalp and automatically subtracts the known pedestal heights from the User marks to determine the 3D locations If the pedestals are tilted or overturned your 3D coordinates will be slightly off Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 12 GPS FAQs Marking the Points Do I mark all the points at one time No there are two main stages cardinal and non cardinal e First mark and edit the cardinal points of the GSN This establishes a control network on which the remaining sensor registration can be based e Second mark and edit the non cardinal points of the GSN Do not mark move or change the cardinal points at this stage Are there sensors do not mark Yes there are e In cardinal mode Do not mark any other sensors except the cardinal points e In non cardinal mode Do not mark the cardinal points e In non cardinal mode Do not mark the common sensor which is directly above the nasion the ear sensors of the GSN 200 or other spacer sensors used to provide stability to the Net structure for example the HCGSN has a bottom row of stabilizer pedestals designed to keep the Net from turning over on the back of the neck these pedestals contain no electrodes and are not numbered During sensor modeling refer to the GSN sensor layou
28. and establish an initial solution set e Mark and solve all the other sensors in the GSN The software uses the cardinal point solutions to anchor its calculations Chapter 7 describes image acquisition Chapter 8 covers sensor modeling Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 27 1 System Overview Operational Overview We recommend practicing the entire acquisition and modeling processes at least once before attempting sensor registration on a subject Figure 1 2 provides a broad outline of typical operational steps using a GPS that has been properly calibrated Image Acquisition eoe Pron coegrareneiry oe ir E RsS i 8j E 1 Bjarki berig han LFE F we it dirii benii Be 18 7 f Dy CI 4 Kumsber ql panumi LIF lt Pudewlal Height FLE i fi M CPi hembar JOONT i T o Center the subject within the dome In the Photogrammetry dialog create a GPS file choose the correct Net size and click Capture Images to view streaming video of the subject Review streaming images to ensure that the subject s head is centered in each camera view and almost no sensors are obscured adjust as necessary Click Take Pictures to capture still images review again click Accept Pictures when satisfied Use the mouse or other pointer to mark visible sensor pedestals on each acquired image click Identify to cross correlate correct sensor IDs an
29. automatically apply the correct calibration values to the files If you recalibrate the GPS Photogrammetry will replace the Precise Camera Description file with the new version and apply the new values to any image sets created thereafter Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 Camera Calibration Calibration File The other file the calibration file can be accessed by the user It is a GPS file that contains the images edits and values produced during the system calibration You can use this file for various tasks For example suppose you recalibrated the GPS and want to apply the new calibration values to a GPS file created before the recalibration 1 Choose View gt Info Window gt Calibration to open the Calibration pane 2 Click the Assign Calibration button navigate to the new calibration file and select it Or if your site has more than one GPS dome there will be more than one calibration file If you are unsure whether your current GPS file is linked to the correct calibration file choose View gt File Info gt General and check the GPS serial number If the number is incorrect follow Steps 1 and 2 above Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 93 6 Camera Calibration 94 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 7 IMAGE ACQUISITION A cquiri
30. cable exiting camera 9 into an unused USB port on the data acquisition computer Do not plug the USB cable into a USB hub Plug the power supply cable exiting camera 9 into the power supply cable exiting the front of the gantry see photo below Power supply cable gantry A Power supply USB cabl TE cable dome At the bottom of the gantry plug the power cord to a 110 127 VAC 60 Hz power supply in the room Power cord for connection to external power supply Figure 2 13 Connecting the power and the USB cables 48 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Computer and Monitor The GPS comes with a data acquisition computer and monitor to acquire view and edit GPS images The computer is an Apple PowerMac G5 and the monitor is a 23 inch Apple Cinema Display Information about both is provided in the GES Hardware Technical Manual and the respective Apple User s Manuals Connectivities The computer serves as the platform for the Photogrammetry image acquisition and review software The computer connects to the GPS hardware via a USB cable see Figure 2 14 which also shows the connectivities for the monitor and the keyboard The keyboard is supplied with a 2 meter USB cable and extensions are available For troubleshooting the monitor keyboard or mouse see the GES Hardware Technical Manual the Apple User s Manual or h
31. cases the Sensor Locations window may list camera views for that point but enclose them in parentheses and not mark the point with the green solved dot You must then double click on the camera list to bring up the 3 Up Model window confirm that the point is correctly cross correlated and verify the point s number with the sensor layout Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 153 12 GPS FAQs 154 If it all checks out select the point in the Sensor Locations window and click the Mark Solved button If it doesn t check out e g if you need to renumber the point or add a User mark in another camera view for triangulation then edit the point assign the correct number and click the Update Model button in the Model window If the point is not automatically marked as solved in the Sensor Locations window then manually mark it as solved using the techniques described in the preceding paragraphs Couldn t just manually number all the points in all the camera views and bypass having to model unsolved points You could try but manually marking all the points takes much more time than marking and editing them using the Photogrammetry software The software automatically numbers most of the sensors and as you gain more experience you will become more skilled at sensor marking and your work will yield higher percentages of solved sensors Also manually mark
32. channel HydroCel GSN v1 0 Adult 182 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 E Sensor Layouts O Cardinal point Figure E 4 128 channel GSN 200 v2 0 Adult Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 183 E Sensor Layouts O Cardinal point Figure E 5 128 channel HydroCel GSN v1 0 Adult 184 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 E Sensor Layouts Figure E 6 256 channel GSN 200 v1 0 Adult Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 185 O Cardinal point Figure E 7 256 channel HydroCel GSN v 1 0 Adult 186 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Geodesic Photogrammetry System Technical Manual GLOSSARY A algorithm A step by step problem solving procedure aliasing 1 In terms of graphics this occurs when a computer monitor printer or graphics file lacks the resolution to represent a graphic image or text smoothly the result is often called the jaggies 2 In terms of EEG this occurs when the EEG signal is digitized at a rate less than half the highest frequency present antialiasing 1 In terms of graphics this is the smoothing or blending of the transition of pixels in an image Antialiazing the edges of a graphic image makes t
33. colored symbols so you can view your progress while marking the sensors and detect poorly placed marks immediately You can delete edit or reselect sensors using a variety of windows and tools Sensor modeling differs from calibration modeling in that you do NOT number the points when you mark them the software semiautomatically determines the points sensor numbers and positions based on User marks and built in sensor layouts Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 105 8 Sensor Modeling The steps to the sensor modeling process are 1 Using the GSN s sensor layout as a guide mark the cardinal points in each of the 11 camera views cardinal points are defined on page 109 save a copy of the marked up file See Saving File Copies on page 109 2 Inthe original file click the Identify Sensors button to determine the sensors true IDs and to triangulate the cardinal points 3D locations The software is designed to minimize false positives and will often regard some correctly marked points as unsolved If an error message appears you must a edit unsolved points in the camera views correcting for poor placement incorrect numbers too few or too many User marks for a sensor etc and b click the Identify Sensors button If an error message appears again you must a review the User marks in each camera view b correct the marks usin
34. if the system is powered off and the power cord is unplugged from the outlet Caution Removing any of the outer panels of the GPS or disassembling the system in any way may defeat electrical safety Cleaning To clean the GPS safely e Switch the GPS off before cleaning e Prevent any liquid or sterilized agent from entering the GPS e Do not use abrasive products e Use a soft brush to remove dust from cracks and near connectors e Clean the external surface with a cloth lightly soaked with lukewarm water and a gentle detergent based on neutral soap e Dry with a clean dry lintfree cloth Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 55 56 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 4 SOFTWARE INSTALLATION his chapter provides general information about the software such as system requirements GPS package contents installation file organization and Net Station startup System Requirements The Photogrammetry module operates within Net Station 4 0 or later on Macintosh OS X version 10 2 or later The minimum recommended configuration is a desktop Power Macintosh G5 The module is designed to perform well on computers with at least a 500 MHz processor and 512 MB of RAM GPS Package Contents The GPS software package includes e The EGI Net Station CD e HASP key e The Geodesic Photogrammetry System Technical Manu
35. message appears you must edit some of the User marks Incorrect number of cardinal points please re check point locations and try again or solve If no error message appears you may still manually if necessary View 1 Up a1 3 Up 63 All Images HA Model HM Observations Sensor Locations Info Window al Compare Nets 173 3 4 8 36 1 2 6 67 6 10 11 257 1 4 5 4 8 9 72 5 6 10 5 9 10 4 5 9 3 7 8 1 2 3 151 Mark Solved 112 need to solve any remaining unsolved points before exporting the cardinal point solution see Chapter 9 Data Export or marking the non cardinal points see Marking the Non Cardinal Points on page 117 In either case save a copy of the identified file before proceeding to Step 5 See Saving File Copies on page 109 5 To edit the User marks choose View gt Sensor Locations to open the Sensor Locations window For more guidance see Tips on Editing the Cardinal Points on page 114 The Sensor Locations window allows you to view the unsolved points and to sort the points by number camera solved status RMS or coordinates Sensor Locations 6 Click on the Solved column and on the sort toggle arrow button to view the solved N Number Cameras 0E evs coordinare cardinal points In this example sensor 31 is 1 291 2 000 0 616 2 000 1 633 1 291 1 915 1 291 1 528 1 732 0 000 0 000 0 000 missin
36. preauricular points and then export the data to the BESA or EMSE format So registering sensors with the GPS requires user interaction Yes you must mark and edit the points The GPS is semiautomated after you mark the points the software determines the sensors correct numbers and positions for you It also directs you to points that require additional editing One major advantage of the GPS is that it is forgiving Your work is editable so if you make a mistake you can correct it and continue with your work Or if there are too many errors to sort out you can go back to Square One by choosing View gt Info Window and clicking the Revert to Start button to clear all marks in all camera views or by choosing Edit gt Clear to clear all marks in a selected camera view An alternate method is to save a copy of your file after marking all points and identifying the data set during cardinal and non cardinal modes This method allows you to return to the previous version of the file How long does it take to solve a file from start to finish The answer varies depending on user experience skill level and GSN model For a newcomer working with a 256 channel GSN it may take two hours or more for experienced users it can take as little as 30 minutes Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 149 12 GPS FAQs 150 Acquiring the Images Is the lighting in my room with
37. resulting Acrobat Touch Up Image file using a graphics editing program and save in the appropriate format TIFF Images To obtain an image of the contents of a camera view only Option click in the camera view and drag the image to the Desktop Open the resulting TIFF file 640 x 480 using a graphics editing program and save in the appropriate format Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 145 11 Printing GPS Images 146 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 12 GPS FAQS T he GPS represents an elegant way to register your sensor positions As with all tools however using the GPS successfully requires some practice Fortunately the GPS allows you to work on the acquired images for as long as you need If editing the marked sensors proves problematic you can erase the marked points and start from the beginning The software provides the ability to clear all marked points from all camera views see Revert to Saved button on page 68 or from a specific camera view see Clear menu command on page 65 Note An alternate method is to save a copy of the file with all relevant points marked or identified to which you can return See Saving File Copies on page 109 for more information This chapter contains frequently asked questions FAQs about the GPS that are designed to help you mark and edit sensors
38. shows the 3 Up Acquisition window Ls 1 a n olla 2 ha Camera 1 g z Click the 3 Up 3 g button middle to view camera 4 triads 5 6 Wershon 1b Figure 7 3 3 Up Acquisition window The following are brief descriptions of the numbered items from Figure 7 3 1 Camera view buttons Allow you to view the subject from the viewpoint of one camera three cameras or 11 cameras These buttons are visible in all Acquisition and Model windows 2 Take Pictures button Triggers the shutters for all cameras and saves all resulting images to memory This button is visible in all three Acquisition modes 3 Accept Pictures button Writes the images in the current GPS file s memory to disk This button is visible in all three Acquisition modes and is unavailable if no images are stored in memory 4 Navigation tool Consists of a dynamic graphical representation of the GPS dome and forward and backward buttons Figure 7 4 This tool is visible in 1 Up and 3 Up Acquisition and Model windows It is not visible in any All Up modes 100 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 7 Image Acquisition GPS dome highlights in color the currently selected camera or camera triads To navigate to specific cameras a click on individual cameras or in the j space between triads Va E na Forward and backward buttons cycle 4 x Fj gt through single camera selection in
39. solved 6 Repeat Steps 2 5 for all other sensors with the unsolved or questionable status Non Cardinal Point Instructions Modeling the non cardinal points is nearly identical to the cardinal point process Marking the Non Cardinal Points e Follow the hints and steps in Tips on Marking the Cardinal Points on page 114 except mark the other sensors Do not change the marks or labels for the cardinal points e Do not mark the common sensor which is directly above the nasion the ear sensors of the GSN 200 the bottom three rows of the 256 channel GSN 200 or other spacer sensors used to provide stability to the Net structure for example the HCGSN has a bottom row of stabilizer pedestals designed to keep the Net from turning over on the back of the neck these pedestals contain no electrodes and are not numbered During sensor modeling refer to the GSN sensor layout for the correct sensors e After marking all the non cardinal points save a copy of the marked up file see Saving File Copies on page 109 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 117 8 Sensor Modeling 118 Editing the Non Cardinal Points e Follow the hints and steps in Tips on Editing the Cardinal Points on page 114 except edit the other sensors Do not change the marks or labels for the cardinal points e Innon cardinal mode you will click the Identify Sensors bu
40. some points to keep in mind before you begin the HASP key updating process Step by step instructions for updating EGI licenses follow the tips 2 Compress the file and email it to EGI 1 Generate an 3 Update file from EGI will update your HASP key the file and email it to you 4 Uncompress the Updated file and use it to update your HASP key Success lt gj Figure B 1 Overview of the license updating process Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 161 B Updating EGI Licenses Tips on Updating EGI Licenses File compression Before emailing i 3 NutCase Binhex your Update file to EGI compress the e Drop files onto this window to process Binhexed files will be file USING aq software program such as unpacked others will be binhexed Binhex option on to safeguard against file corruption during the email process keys The HASP key that created the Update file must be plugged in when the Updated file from EGI is applied to update the license Note You may have multiple HASP keys with the same name followed by a number The number of the HASP key must match the number of the Update file when updating AS Ong Cham ngx Unique HASPs Updated HASP files J are unique to their individual HASP E HASP names To determine which HASP key is which launch Net
41. subjects and clinical patients e In general a minimal amount of special fonts is used italics for definitions or newly introduced terms boldface italics for important concepts or for special emphasis and boldface for command paths for example File gt Open Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 xxi Preface Additional Information Three different methods are used to convey additional information notes cautions and warnings Note This indicates information that ts helpful in understanding GPS operations Caution This denotes important information that if unheeded could hinder use of the product or result in injury or equipment damage WARNING This denotes important information that if unheeded could result B in serious injury or death Support and Resources e For online updates to this book check EGI s Documentation page at www egi com documentation html e For GPS technical support see Appendix A Technical Support xxii Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 1 SYSTEM OVERVIEW he Geodesic Photogrammetry System GPS increases the convenience and accuracy of sensor registration by dividing the process into two steps image acquisition and onscreen sensor modeling The two main advantages of this division are e Subject time is minimized during image acquisition Acquiring images
42. the gantry lifts and lowers the dome Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 35 2 Hardware Assembly Figure 2 3 shows the gantry s main parts left arm Dome support x 5 Motorized control Q right arm Back lt q i Front Top view Side view Main body Straps Rolling base internal supports Figure 2 3 The gantry s main body straps attached to body s interior and rolling base Assembled the gantry measures 110 5 x 84 x 145 42 cm l x w x h see Figure 2 4 height 145 42 cm O O width 84 cm length 110 5 cm Figure 2 4 Dimensions of the assembled rolling gantry front left and side view right 36 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Assembling the Gantry The gantry is shipped with three sets of bolts fastened in their correct locations on each arm of the rolling base The bolts are located in the front bottom and strap positions see Table 2 5 and Figure 2 5 Table 2 5 Rolling base bolt sets Location Components Photo of right arm of rolling base Front 1 4 20 x 3 4 bolt 2 1 4 flat washers 1 4 20 hex nut Bottom 3 8 16 x 2 1 2 bolt 2 3 8 flat washers 3 8 16 hex nut Strap 1 4 20 x 3 4 bolt and 1 4 washer Front Bottom Strap Front Bottom Figure 2 5 Another view of the positions of the front bottom a
43. the sensors on the head 32 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Labels and Symbols 2 Hardware Assembly Table 2 3 shows and defines the labels and symbols used on the GPS equipment Table 2 3 Labels and symbols Symbol Description Tipping hazard Symbol Do not tp System greater than 10 degrees in any direction as damage or inpury may nesult Lise caution when meving Vieight 77 bg 170 bs Description Moving warnings for text see Moving Warnings on page 54 Electrical hazard Only authorized personnal mary sonace hig equipment Hazardous mains voltage inside Disconnect power belone servicing 10 proveni damage or injury Grounding neiabdity can only be achieved when equipmend is connected to an equivalent rceptech marked Hospital Only of Hospital Grada Wee a properly grounded cutat to proveni damag or injury Grounding warnings for text see Grounding Warnings on page 54 ESLA 35 F 0e 50 F 5 95 SG PD gh Temperature limits Humidity limits Moving parts are a pinch and resh hazard Keep all clothing hair and body parts wall away from moving parts and use caution when operating Io presari injury See manual for important operating instructions and salty information bilori operating Moving parts ara a pinch and eneth hazard Keep all clothing hair and body paris wall away
44. the above step and report the problem to EGI Contacting EGI EGI Support web page www egi com support html Email support support egi com Sales info egi com information Telephone 541 687 7962 Fax 541 687 7963 Address Electrical Geodesics Inc 1600 Millrace Drive Suite 307 Eugene OR 97403 USA S MAN 200 GPSR 001 e November 22 2006 159 A Technical Support 160 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 appendix B UPDATING EGI LICENSES EGI protects its software from unauthorized use by encoding licensing data in HASP keys If you have purchased a complete EGI EEG System the HASP key is attached to the system cart handle If you have purchased only the Net Station software the key is HASP key included in the software installation package PO Pi A HASP key is a small hardware device sometimes called a dongle that you plug into a computer s USB port The information in the HASP key tells Net Station whether you are allowed to use the software All authorized Net Station users have a HASP key To update your EGI license do not send EGI the actual hardware key Instead you will need to generate a computer file from the HASP key and email the file to EGI which will update the licensing information in the file and email it back to you Use the edited HASP file to update your software See Figure B 1 Figure B 2 lists
45. to be installed and put into service according to the EMC information provided in this appendix The EMC information is encapsulated in the following tables e Table C 1 on page 168 electromagnetic emissions for the GPS e Table C 2 on page 169 electromagnetic immunity for the GPS e Table C 3 on page 170 electromagnetic immunity for non life supporting equipment such as the GPS e Table C 4 on page 171 recommended separation distances between radio frequency RF communications equipment and the GPS Note Portable and mobile RF communications equipment can affect the GPS WARNING The use of accessories and cables other than those that ship with the gt GPS with the exception of those sold by EGI as replacement parts for internal components may result in increased emissions or decreased immunity of the GPS WARNING The GPS should not be used adjacent to or stacked with other c gt equipment If adjacent or stacked use is necessary the GPS should be observed to verify normal operation in the configuration in which it will be used Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 167 C EMC Declarations for GPS Table C 1 lists the EMC emissions guidelines and declarations for the GPS Table C 1 Electromagnetic emissions for GPS The Geodesic Photogrammetry System GPS is intended for use in the electromagnetic environment specitied below The customer or the user of the GPS sho
46. triangulation solutions O unacceptable triangulation solutions Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 of Observations indicates the total number of User marks made on the Solved Sensor Locations displays the number of sensor locations with Unsolved Sensor Locations displays the number of sensor locations with 67 5 Startup and Menus Revert to Saved button opens the OK to Revert dialog requesting confirmation to clear User marks from all images Figure 5 8 This action is irreversible so use with care OK to Revert Clicking Revert will clear all points in all views Are you i sure you wish to revert Figure 5 8 OK to Revert dialog Assign Subject If no subject is assigned to a file the Assign Subject button is visible Clicking this button opens the Select Subject window see Figure 5 3 on page 63 Note that a calibration file has no subject The resulting GPS solution set is then saved to that subject which is used by the Viewer and Waveform Tools e Calibration Provides information about the calibration values applied to the current GPS file Figure 5 9 shows the Calibration pane Chapter 6 Camera Calibration describes this pane in detail 099e calib 2004Sep02_lc Info General alibration Linear Parameters Radial Parameters a 16 3784 Radius 50 0000 b 1 3129 Theta 0 0000 c 7 4862 Phi 0 0000 d 374 3120 Theta Or
47. typically takes less than 5 minutes e Sensor registration is editable You can correct errors or improve the accuracy of the sensor registration through careful work with the acquired images This chapter introduces you to the GPS Included are descriptions of the intended use hardware design operational theory and operational overview Intended Use The GPS is intended for use in recording precise locations of EEG electrodes in the Geodesic Sensor Net GSN on a patient s or subject s head Hardware Design The main GPS hardware consists of a geodesic dome attached to a motorized gantry Figure 1 1 which lifts and lowers the dome over a subject wearing a GSN The dome is in the shape of an icosahedron with the bottom removed and a camera is mounted Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 23 1 System Overview at each of the 11 remaining vertices Other standard GPS hardware includes the data acquisition computer and the monitor Figure 1 1 A top view of the dome and its 11 cameras left and attached to the gantry right Chapter 2 describes the GPS hardware in detail and provides step by step assembly instructions Operational Theory The aim of photogrammetry is to reconstruct a 3D world from 2D images The basic principle is triangulation which mathematically intersects lines of sight extending from multiple cameras to a point on the object to produce a 3D co
48. well as for the User marks Click on the EGI Head Model 3D Point Cloud and Numbers buttons to project them onto the images You can apply overlays in the 1 Up or 3 Up window To apply an overlay to all the camera views in the 3 Up window simultaneously Command click on the overlay button EGI Head Model Figure 8 15 shows the EGI Head Model overlay HeatherCompletelysolved EGI Head Camera 1 F ew Model C button o o P o 9 k li A 2 u o o kki 3 o b Os E a o s 5 a i k EGI Head o e i j k Model applied o ot E S o D p 5 0 r 5 a A D A o 5 o O Figure 8 15 The EGI Head Model overlay When you click the EGI Head Model button the software overlays the EGI Head Model points onto the acquired images displaying it in purple type 126 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling The EGI Head Model is best for verifying the accuracy of the mapping of the points It can also help you identify User marks that are incorrectly numbered view the numbers by clicking the Numbers button This is useful in 3 Up mode which displays up to three views in which the sensor is marked To renumber a point double click on the User mark to open the Change Number dialog and assign the correct number according to the EGI Head Model Note After cardinal points are solved the EGI Head Model ts scaled to fit the solved car
49. 0 GPSR 001 e November 22 2006 155 12 GPS FAQs 156 Photogrammetry Error Messages This section provides a table listing Photogrammetry error messages and their solutions Table 12 1 GPS error messages Category Message Solution General Controller has been Check USB cables and connections from disconnected Please check dome to gantry from gantry to the USB cables computer and so forth Calibration All points must be solved All targets must have their solved state before cameras can be set to true for the calibration to be calibrated successful Make sure all the targets have been marked solved in the Sensor Locations window Calibration There are not enough points You have not accounted for all the to calibrate the cameras targets on the Calibration Object Check that all targets are marked in at least two cameras and correctly numbered then manually mark them as solved in the Sensor Locations window Calibration RMS error is high Camera did Make sure your marks are cross not calibrate correctly Please correlated to the correct target Make check points and re calibrate sure the targets are numbered correctly Add remove or move points as needed Acquisition Unable to find camera The GPS cannot find all the cameras to establish connection and start up This is usually caused by lighting or contrast issues Adjust room lighting or place a person in the dome to provide suffici
50. 1 e November 22 2006 119 8 Sensor Modeling SS 4 Mode indicator Displays whether the file is in cardinal or non cardinal mode The default is cardinal mode once the cardinal point data set is solved the mode automatically changes to non cardinal Non Cardinal Mode Mode indicators 5 Camera view Shows the captured stills for the current cameras The images are clickable and editable 6 Camera label Indicates the camera associated with the view Select Points for Calibration 7 Task indicator Reminds you of the task to be performed in the window This a indicator is helpful if a break occurs during the sensor modeling process Select Non Cardinal Points Data ready for exporting Task indicators 1 3 Up Window The 3 Up window displays trios of images called triads from adjacent cameras Images are displayed in full scale 1 1 but depending on monitor resolution you may need to use scroll bars to see the entire images Double click in one of the three camera views to display that image in the 1 Up mode Because the cameras are adjacent the triads represent cameras most likely to be involved in triangulating a point Therefore i you can use the 3 Up window to verify that a point has been la A correctly mapped by viewing it from the cameras that were used lg oy S in the triangulation or to find another camera view in which to V0 mark the point Navigation tool forward button The default c
51. 2 on page 135 for a picture of this operation 3 To edit User marks In each camera view check the placement of the User mark compared with the pedestal center a move it if necessary and b click the Update Model button in the 3 Up window Use the sensor layout to verify the Change Number numbering of the point in each of its Ba camera views if the software misnumbered the sensor you can a double click on the User mark in the Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling camera view to open the Change Number dialog b type the correct number in the dialog c click OK to close the dialog and d click the Update Model button in the 3 Up window If the sensor is marked in only one camera view you can a use the sensor layout to find the sensor in the another camera view b mark and label the sensor and c click the Update Model button in the 3 Up window If the sensor is marked in more than two camera views you can a delete the User mark from a camera view with poor line of sight to the sensor and b click the Update Model button in the 3 Up window 4 Click the Update Model or Identify Sensors button in the Model window depending on whether you are working with an identified solution set 5 Inthe Sensor Locations window select the point and click the Mark Solved button if it is not already marked as
52. 22 2006 63 5 Startup and Menus 7 Capture Images button Signals the software to establish communication with each camera A streaming video feed of the subject appears in the resulting Acquisition window See Chapter 7 Image Acquisition for more information 8 Open Dataset button Automatically opens the most recent dataset when clicked immediately after image acquisition Photogrammetry Menu Bar The Photogrammetry menu bar contains seven menus Net Station File Edit Docs Tools View and Actions Figure 5 4 Net Station 4 2 File Edit Docs Tools View Actions Figure 5 4 Photogrammetry menu bar In general the Net Station File Docs and Tools menus are standard Net Station menus The Edit View and Actions menus contain commands specific to Photogrammetry This section discusses the Edit View and Action menus first Descriptions of the remaining menus and how to open a GPS file round out the chapter 64 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 5 Startup and Menus Edit Menu The Edit menu is available only in the 1 Up Model window Figure 5 5 shows the Edit menu Net Station 4 1 File Em Docs Tools View Actions r 00900 ndi calib 2004Sep02kenn J Seo _4 Cut a A Pi amp ET Camera 1 s tg Ti C Calibrate ste f X Update Select Points
53. 4 20 x 2 bolts 1 4 20 x 3 bolts dome support dome support Figure 2 11 Pipe clamp configurations 46 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 1 Use a straight edge and or a level to verify that the dome tubing is straight If any tubing is bent contact EGI Technical Support Appendix A 3 Power and USB cables exit camera 9 which is the hub Tubing connects camera 9 to cameras 4 and 5 The tubing between cameras 4 and 5 5 and 9 and 9 and 4 are where the dome connects to the pipe clamps 2 Hardware Assembly 2 The dome support on the gantry contains three pipe clamp sets Unscrew the acorn nuts and remove the top half of each pipe clamp set leaving the bottom halves connected top half bottom half dome support 4 Lock the front wheels of the gantry Have a colleague line up the dome with the pipe clamps and hold the dome in place Connect the dome by hand tightening the top half of the pipe clamps and the acorn nuts over the tubing on the vertical arm Hand tighten the pipe clamps and nuts over the tubing on the horizontal arm Tilt the dome up and down to ensure that the tubing is straight adjust dome as needed Using the wrenches tighten all six acorn nuts Figure 2 12 Dome assembly process Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 47 2 Hardware Assembly After the GPS is assembled plug the USB
54. 4 20x 3 4 F bolt Rolling base Front of gantry Strap bolt m 1 4 20 washer 1 4 20 x 3 4 bolt Rolling base Inside of gantry j Figure 2 8 Gantry bolt sets at three main connection points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Al 2 Hardware Assembly Dome Overview The dome is a single welded aluminum unit that measures 102 x 102 x 89 cm lx w x h see Figure 2 9 A pentagon shaped container at each of the 11 vertices holds a circuit board mounted with a camera a Universal Serial Bus interface and a ring of high intensity white LEDs USB cables pass through the hollow aluminum tubes of the dome supplying power to the cameras and linking each camera to the hub which is housed in camera 9 Top level 1 3 4 ym Second level 2 6 clockwise 60 O A 3 Third level 8 7 7 11 9 clockwise 10 Hub Power cable exiting the hub USB cable exiting the hub Gantry Front of GPS 102 cm Figure 2 9 The dome structure with cameras numbered for identification A USB cable exits camera 9 and connects to a USB port on the data acquisition computer 42 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Note Do not plug the USB cable into another USB hub Running the cable through the hub may result in poor quality images A power supply cable also exits camera 9 and plug
55. 60601 1 EN60742 IEC601 1 CE Mark Power Selectable 115 or 230 V 50 60 Hz input output Leakage current lt 100 uA Outlets Appliance type IEC 60320 Miscellaneous Low weight magnetic strayfield mechanical noise and losses high efficiency 50 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Table 2 10 GPS power values Monitor only 80 VA DAC only 150 VA Gantry motor only 150 VA Gantry motor and dome 170 VA Full system DAC monitor dome and gantry 275 VA attached but inactive Full system acquiring video lights on gantry 400 VA motor active GPS load on isolation transformer 170 VA gantry and dome Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 5I 2 Hardware Assembly 52 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 3 SAFETY fter installing the hardware read the cautions and warnings in this chapter before operating the GPS For issues not covered in this chapter contact EGI Technical Support Appendix A The information in this manual is subject to change without notice The manufacturer declines responsibility for the safety reliability and performance of system components if not used in compliance with official documentation WARNING It is important to use the GPS only according to the manufacturer s instr
56. 9 Data Export describes how to export the coordinate data to a text file for use in the third party applications BESA and EMSE Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Preface Chapter 10 Compare Nets describes using the Compare Nets menu command to register sensors before and after an EEG session to measure sensor displacement Chapter 11 Printing GPS Images describes how to print images acquired by the GPS Chapter 12 GPS FAQs lists frequently asked questions regarding overall GPS operations image acquisition and sensor modeling and provides a table of error messages and solutions A number of appendixes are also included e Appendix A Technical Support e Appendix B Updating EGI Licenses e Appendix C EMC Declarations for GPS e Appendix D Calibration Target Layouts e Appendix E Sensor Layouts Conventions and Typography e Inthis manual Geodesic Sensor Net GSN and Net are synonyms and refer generically to both the GSN 200 and HydroCel GSN unless otherwise noted e Inthis manual Geodesic Photogrammetry System and GPS are synonyms and refer to the system in general Photogrammetry refers to the software interface used to acquire images and to mark edit and export sensor locations e The GPS can be used in both research and clinical settings For convenience the manual uses the term subjects to refer to both research
57. 9 Sensor Locations window 116 8 10 All Up Model window 119 8 11 3 Up Model window 121 8 12 Navigation tool 121 8 13 1 Up Model window 123 8 14 The three filtered views Normal Inverse and Onion Skin 125 8 15 The EGI Head Model overlay 126 8 16 The 3D Point Cloud overlay 127 8 17 Numbers applied toa model 128 8 18 The model view in the 1 Up camera view 129 8 19 Observations window 131 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 xi List of Figures 8 20 The selected model number in the acquired image 133 8 21 Sensor Locations window 134 8 22 The selected sensor number in the 3 Up Model window and the model view 135 chapter 9 Data Export 9 1 Skull landmarks 137 9 2 Export process 139 9 3 The Export dialog 140 9 4 An example BESA export file left and EMSE export file right 140 chapter 10 Compare Nets 10 1 View gt Compare Nets 142 10 2 Example results from comparing the sensor registrations of a GSN pre and post exam 144 Appendix B_ Updating EGI Licenses B 1 Overview of the license updating process 161 B 2 HASP updating tips 162 B 3 Open the HASP Updater application 163 B 4 Create the HASP Update file compress it and email it to EGI 164 B 5 Apply the Updated file from EGI to the corresponding HASP 165 Appendix D Calibration Target Layouts D 1 Camera view 1 173 D 2 Camera view 2 174 D 3 Camera view 3 174 D 4 Camera view 4 175 D 5 Camera view 5 175 D 6 Camer
58. Comparison window choose View gt Compare Nets Figure 10 1 shows this window 6080 Net Comparison Mode Number Number Dista em a Sec _ _ _ _ _ E HeatherCompletelysolved2 E Error 0 0 Figure 10 1 View gt Compare Nets BesssessssssssscssscssssssssssescssessssssssessesssssssscssegMcsssscscesscssssscscecssssssssessccsssssssssscsssssssssssssssssssssssssesuees Ox The following are brief descriptions of the numbered items from Figure 10 1 1 File selector Allows you to select a pre or post exam file to compare with the current post or pre exam file Either drag the file into the box or click Select and navigate to the file 2 Net size Displays the GSN model used in the current file 142 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 10 Compare Nets 3 Difference window Calculates and displays the difference between files for each point e Model Number lists the model points by number e Distance indicates the difference in centimeters between files for each model number 4 Model view Displays two superimposed 3D Point Cloud of the files The view scales to fit is always centered and displays all points Green represents points from the currently opened file and blue represents points from the comparison file If the comparison file uses a different GSN model a message appears indicating that the Nets are incompat
59. Figure 6 2 provides a flowchart of the calibration process Place the Calibration Object on its stand and center it within the GPS dome y Open Photogrammetry choose Calibration Object from the Net Size pop up menu and click New Click Capture Images Follow the instructions in Figure 7 1 on page 96 starting with the Click the Take Pictures box Is the object positioned well Reposition the object until all 11 cameras have an unimpeded view Cycle through the camera views correcting misplaced or misnumbered points and click Calibrate Follow the instructions in Figure 8 1 on page 107 except click precisely on the dot in the center of each target visible in each image labelthe point with its assigned number and when done click Calibrate Did you receive an error message Close the GPS file The GPS will automatically apply the calibration values to any images acquired afterward with that dome Figure 6 2 Calibration process Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 77 6 Camera Calibration Image Acquisition Figure 6 3 provides an overview of acquiring images of the Calibration Object Figures 6 4 6 5 and 6 6 provide expanded views of the steps 1 Position the Calibration Object on its stand within the GPS dome so that each target labeled from 1 to 11 is pointing toward its respective camera in the GPS dome lower th
60. Hardware Assembly 44 Table 2 8 identifies the bolts nuts pipe clamps and washers Figure 2 10 indicates the connection points in the dome support and dome Table 2 8 Bolts nuts and washers for dome support Label in ltem Quantity Figure 2 10 Photo actual size 1 4 20 x 2 bolt 4 B 3 8 acorn nut 6 A amp B pipe clamp 3 A amp B 1 4 20 x 3 bolt 2 A 3 8 flat washer 6 A _ Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Key A vertical 1 4 20 x 3 bolt B horizontal 1 4 20 x 2 bolt Figure 2 10 Gantry and dome connection points Figure 2 11 shows the configuration of the pipe clamp sets Figure 2 12 illustrates the dome assembly process Assembly requires one 1 3 8 end wrench and one 1 3 8 socket wrench which are not provided Figure 2 13 shows how to connect the USB and power cables Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 45 2 Hardware Assembly A Three sets of pipe clamps are B A pipe clamp set consists of two separable attached to the dome support halves connected by bolts and nuts bottom half C The pipe clamp on the vertical arm D The pipe clamps on the horizontal of the dome support contains 1 4 20 x arm each contain 1 4 20 x 2 bolts and 3 bolts and uses three washers per bolt use no shims as shims acorn nuts acorn nuts washers 1
61. Identity and model the points as needed Non cardinal mode Not enough points are solved to continue You are in non cardinal mode but have not solved all the cardinal points Check the Sensor Locations window and determine which cardinal points are missing Mark and model them as needed Non cardinal mode Cardinal or non cardinal mode Not enough points have been marked to perform triangulation Please mark more points That number is already taken Try another number You must have at least twice as many User marks as you have points to solve before attempting to identify Add some more User marks You are manually trying to number a User mark with a number already assigned in that camera view Either delete the other User mark or use a different number Cardinal or non cardinal mode Data export Geodesic Photogrammetry System Technical Manual You must enter a positive number All fiducials must be marked and solved in order to export to other file types You are trying to provide a negative value Enter a positive value You are trying to export data that lack marked and solved fiducial points Click a fiducial button and mark the corresponding fiducial in at least two camera views Do this for the other fiducial points S MAN 200 GPSR 001 e November 22 2006 157 12 GPS FAQs Table 12 1 GPS error messages Category Message Solution
62. If the pedestals of the GSN s cardinal points are uncolored color them with a permanent marker being careful not to cover the sensor number Each Net has 6 11 evenly spaced cardinal points which serve as control points for additional sensor modeling Table 8 1 on page 109 lists the cardinal points for the 64 128 and 256 channel GSN 200s and the 32 64 128 and 256 channel HCGSNs e Apply the GSN according to the detailed instructions given in the Geodesic Sensor Net Technical Manual e Verify that the GSN sensors are evenly spaced on the surface of the scalp e Ensure that the subject s preauricular points the indentations in front of the ear flaps where the jaw meets the skull are visible you may want to mark them with round stickers especially if the subject has much hair e Evenly distribute the wires of the GSN 200 as much as possible to prevent sensors from being covered by wires The HCGSN features sleek wire management that groups the wires conveniently Image Acquisition Instructions T Preauricular point Gray s Anatomy Acquiring images of the subject is nearly identical to the process of acquiring images of the Calibration Object Therefore for image acquisition instructions see Figure 6 3 on page 78 and the expanded views of the steps in Figures 6 4 6 5 and 6 6 Note Remember in the Photogrammetry dialog to select the correct GSN model worn by the subject from the Net Size pop up
63. If unsatisfied repeat Steps 6 9 Teleit PHAN Mei Caliratien Figure 6 6 Expanded view of Steps 7 9 in positioning the Calibration Object for image acquisition Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 6 Camera Calibration Red Tints If a red tint covers a camera view it may indicate any of the following e USB problems e lighting difficulties e sudden movements within the camera view To remove the tint try any of the following e Click the Capture Images button again to reinitiate the connection between Photogrammetry and the camera e View each image in the 1 Up mode to individually establish the connection to each camera and then view the images in All Up e Restart the application to clear the USB connection e Ensure that the lighting in the room is even and diffuse open curtains or blinds for more natural light if needed If problems persist contact support egi com Modeling the Targets Marking and editing the targets requires careful work Depending on user experience it can take 15 25 minutes to mark the Calibration Object Save regularly in case the application unexpectedly quits Figure 6 7 provides an overview to marking and editing the calibration targets Figures 6 8 6 9 and 6 10 provide expanded views of the steps Calibration Target Maps If you cannot easily read the numbers of the calibration targets in the acquired images see Appen
64. Manual S MAN 200 GPSR 001 e November 22 2006 C EMC Declarations for GPS Table C 4 lists the recommended distances between the GPS and RF equipment Table C 4 Recommended separation distances between portable and mobile RF communications equipment and the GPS The Geodesic Photogrammetry System GPS is intended for use in an electromagnetic environment in which radiated RF disturbances are controlled The customer or the user of the GPS can help prevent electromagnetic interference by maintaining a minimum distance between portable and mobile RF communications equipment transmitters and the GPS as recommended below according to the maximum output power of the communications equipment Rated maximum output power of transmitter in watts Separation distance according to frequency of transmitter 150 kHz to 80 MHz in meters 80 MHz to 800 MHz 800 MHz to 2 5 GHz d 1 2 VP d 1 2 VP d 2 3 VP 0 01 0 12 m 0 12 m 0 23m 0 1 0 38 m 0 38 m 0 73 m 1 2m l2 m 23 m 10 3 8m 3 8 m 7 3m 100 12m 12m 23m For transmitters rated at a maximum output power not listed above the recommended separation distance d in meters m can be estimated using the equation applicable to the frequency of the transmitter where P is the maximum output power rating of the transmitter in watts W according to the transmitter manufacturer Note 1 At 80 MHz and 800 MHz the separation distance for the higher frequency ra
65. Marking the Cardinal Points Marking cardinal points requires careful work Remember to e Save your work regularly in case the application unexpectedly quits e Click in the center of the pedestal top not where the sponge contacts the scalp Pedestal heights will be automatically subtracted later e Do not number the points the software will do this for you during the identification process Caution Mark only cardinal points during Cardinal mode Marking other sensors will invalidate the process Tips on Editing the Cardinal Points The incorrect number message can be evoked by a number of situations e Asensor is imprecisely marked e A sensor is misnumbered in one of the camera views e A sensor is marked in only one camera view e A sensor is marked in more than three camera views and some of the marks are in views that offer poor line of sight to the sensor the sensor is on the edge or underside of the head for example Following are descriptions of various tools to use to fix these problems Software Tools In the camera views the software indicates whether a point is solved unsolved or questionable by using different colors to represent a point s status in the camera views Figure 8 7 e pink for questionable e blue for solved cardinal points e light blue for unsolved cardinal points e bright green for solved non cardinal points e khaki green for unsolved non cardinal points Note Ques
66. Photogrammetry System Technical Manual Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 November 22 2006 Electrical Geodesics makes no warranty or representation either express or implied with respect to this manual its quality E G l accuracy merchantability or fitness for a particular purpose In no event will Electrical Geodesics be liable for direct indirect special incidental or consequential damages resulting from any defect or inaccuracy in this manual even if advised of the possibility of such damage dense array EEG Copyright 2006 by Electrical Geodesics Inc All rights reserved CONTENTS List of Figures ix List of Tables xv Preface vii About This Manual xix Support and Resources xxii chapter 1 System Overview 23 Intended Use 23 Hardware Design 23 Operational Theory 24 Operational Overview 28 chapter 2 Hardware Assembly 31 GPS Environmental Conditions 32 Site Requirements 32 Labels and Symbols 33 Overall System Dome and Gantry 34 Assembly Instructions 35 Computer and Monitor 49 Isolation Transformer 50 chapter 3 Safety 53 General Safety Warnings 53 Moving Warnings 54 Grounding Warnings 54 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 V yi Contents chapter 4 chapter 5 chapter 6 chapter 7 chap
67. SD TISA TOOT are needed for GPS triangulation three marks are 37 0 000 8 593 5 510 3 484 N A 38 0 000 7 479 6 589 4 426 idea l 39 0 000 6 285 7 363 5 373 Mark Solved a 8 In the 3 Up window view sensor 31 come IO bo Tel using a camera triad that includes camera 2 e g 2 7 11 You can open the 3 Up window by double clicking on the point s camera list in the Sensor Locations window or by clicking the 3 Up button in the Model window 0 000 10 130 1 439 2 848 camera list in the Sensor Locations window 3 Up button in the Model window 9 Click the pedestal of sensor 31 in either of the other camera views and click the Identity Sensors button the software will automatically number the User mark and the cardinal point solution will be identified if fi AELE TESES g r This has been an easy data set to model ap AF in ae Se Gy Oo Gi Solving for non cardinal points is much more 5 a N complicated because of the greater number of points and therefore User marks involved With the hundreds of User marks in a non cardinal set you will have to refer to the sensor layouts and use the modeling tools see pages 114 124 and 131 to solve the unsolved or questionable points Figure 8 6 Expanded view of Steps 7 9 in marking and editing cardinal points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 113 8 Sensor Modeling 114 Tips on
68. Sensor Modeling Selecting Rows If you double click on an item in a row in the Observations window the 1 Up window appears with the selected model number circled in the image Figure 8 20 666 Observations calibration ob SOG id ir ee h y E C Th ba ao iyo Fi F in iii bs f F j F ria r hy r al ie hy a i H i e EN I i Lk k k 7 ra bi hi mi j pi po pl ee l ee ee ee ee i mi 8 a ee eo ee ee eo oe 13 19 l 14 10 tow 15 Fa Double 16 i I z clicking in a z i row displays 3 17 window with the model i a 7 b d P 13 number circle 5 Li 41 Fi it a0 13 ai E a I4 l oo f Diere Y clear soed ee Sees E oe sees se Se Se es ee eS Sree SS eee eel Figure 8 20 The selected model number in the acquired image Sensor Locations Window Choose View gt Sensor Locations to open the Sensor Locations window which displays 3D information based on estimated or triangulated 3D sensor locations This window is useful for solving 3D positions Changes made in this window propagate to both the camera views and the Observations window Figure 8 21 shows the Sensor Locations window Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 133 8 Sensor Modeling 134 1 2 3 4 To open 5 choose Views gt 6 Sensor Locations l ensor Locations 3 109 4 546 4 822 6 403 4 435 5 598 r rnan
69. Subjects Figure 5 1 Starting Photogrammetry Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 5 Startup and Menus The Photogrammetry mode is independent of the other Net Station functions All other features such as Waveform Tools are described in their respective manuals Photogrammetry Dialog Figure 5 2 shows the Photogrammetry dialog The dialog contains the Net Size pop up menu for indicating the GSN model worn by the subject patient This information enables the Photogrammetry software to use the correct EGI head model for sensor registration and modeling Caution Be sure to select the correct GSN model After the photos are acquired and the subject dismissed the Photogrammetry software provides no means for changing this information 00o Photogrammetry To open a Click the Photogrammetry 1 New close untitled l button in the Net Station start up window or choose 2 Net Size Geodesic Sensor Net 128 2 1 Tools gt Photogrammetry Name Geodesic Sensor Net 128 2 1 To close Se Click the red button in the top left corner of the Pedestal Height 2 10 P Photogrammetry dialog 2 GPS Number 20020000 An Assign Subjects 6 button is visible ifno 7 subject is assigned 8 Figure 5 2 The Photogrammetry dialog z Capture Images Version 1 0a4 The following are brief descriptions of the numbered items from Figure 5 2
70. Tools The Modeling tools duplicate selected controls in the Model window e Observations opens the Observations window see Observations Window on page 138 e Sensor Locations opens the Sensor Locations window see Sensor Locations Window on page 140 66 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Into Window 5 Startup and Menus The Info Window contains uneditable information that describes the file The information panes include General Calibration and Log e General Provides an overview of the file Figure 5 7 shows the General pane 808 calib 2004Sep02_Ic Info Calibration Log Date Time Thu Sep 2 2004 11 35 58 AM Hardware Number 20040105 Net Calibration Object 1 0 Fiducial mapping and pedestal heights box of Observations 88 Solved Sensor Locations 33 f Revert to Start Unsolved Sensor Locations 3 Subject Not Applicable Figure 5 7 View gt Info Window gt General Following is a list of the pane contents Date Time indicates the date and time the GPS file was created Hardware Number shows the serial number of the GPS dome that produced the current file Net indicates the GSN model number O Fiducial mapping and pedestal heights box displays the fiducial mapping performed and the pedestal height in millimeters of each measured sensor O acquired images O acceptable
71. X 10 2 02 gt 0 UninstallerData 7 7 03 gt 0 Utilities 5 2 03 66969 J Net Station p fem mM Fs I Back Forward View Computer Home 5 items 126 MB available Name Date Modified _ 5 Open the Extras folder and Ge Net Station 8 7 03 double click on the NS Y F Extras 717103 Sy Net Station File Exporter Fi 03 Remote HASP Updater icon to Cas Ramite HASP Updater 7 7 03 launch the application and Event Timing Tester 7 7 03 open the Updater dialog Figure B 3 Open the HASP Updater application Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 163 B Updating EGI Licenses Generating the Update File 1 Make sure that the a Net Station Remote HASP Updater Create Update File tab is ee frontmost in the Updater E A eate Update Fil Update HASP dialog nt anai Click the button to create a HASP Update File on your Desktop ke named NS Ling Chan Send this file as an attachment to 2 Click the HASP file button support egi com 3 The Update dialog will automatically close and an Update file will appear on your Desktop with the filename NS xxxx where xxxx is the license holder s name If you have y more than one HASP the number of the HASP will be si ESEN appended e g NS Ling Chan NS Ling Chan 1 4 Compress the file using a software program such as NutCase Binhex www bl
72. a view 6 176 D 7 Camera view 7 176 D 8 Camera view 8 177 D 9 Camera view9 177 D 10 Camera view 10 178 D 11 Camera view 11 178 xii Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 List of Figures Appendix E Sensor Layouts E 32 channel HydroCel GSN v1 0 Adult 180 E 2 64 channel GSN 200 v2 0 Adult 181 E 3 64 channel HydroCel GSN v1 0 Adult 182 E 4 128 channel GSN 200 v2 0 Adult 183 E 5 128 channel HydroCel GSN v1 0 Adult 184 E 6 256 channel GSN 200 v1 0 Adult 185 E 7 256 channel HydroCel GSN v 1 0 Adult 186 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 xiii List of Figures XIV Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 LIST OF TABLES chapter 2 Hardware Assembly 2 1 Overall operating environment 32 2 2 Site requirements 32 2 3 Labels and symbols 33 2 4 GPS hardware 34 2 5 Rolling base bolt sets 37 2 6 Bolts nuts and washers for gantry 38 2 7 Dome support bolt sets 43 2 8 Bolts nuts and washers for dome support 44 2 9 Isolation transformer specifications 50 2 10 GPS power values 51 chapter 7 Image Acquisition 7 1 Subject positioning tips 98 chapter 8 Sensor Modeling 8 1 Cardinal points for the GSN 200s and the HCGSNs 109 chapter 9 Data Export 9 1 Fiducial points per camera view 138 chapter 12 GPS FAQs 12 1 GPS error messages 156 Geodesic Photogrammetry System Tech
73. ackdiamond co za bdtfreex html or Stufflt with the Binhex option on www stuftit com mac standard This will ensure that your file is not corrupted in transit Note that this operation must be performed on a Macintosh computer not a PC O NutCase Binhex Drop files onto this window to process Binhexed files will be unpacked others will be binhexed 5 Email the compressed file to support egi com and include in the email message your name the license holder s name if you are not the licensee your organization and a description of what a must be updated For best results email the file from the Macintosh computer that generated it Or you can copy the file to a Mac HFS formatted removable drive transfer it to another Mac and email it Do not email it from a PC Files left to process 0 6 Delete the HASP Update file and any previous compressed copies from your Desktop AS Ling Chan ngx 7 EGI will modify the file updating your license and email it back to you typically within two to three days Figure B 4 Create the HASP Update file compress it and email it to EGI 164 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 B Updating EGI Licenses Applying an Updated File 1 Save to the Desktop the Updated file from EGI uncompressing it if needed 2 Quit Net Station if necessary 3 Insert the corresponding HASP key into the USB port at the side of you
74. al The EGI Net Station CD contains everything you need to install and run Photogrammetry including the Net Station Photogrammetry installer For a complete listing of the CD contents see the ReadMe file on the CD Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 57 A Software Installation E Fi HASP key 58 A HASP is a security device designed to provide authorized users access to the software A HASP is a hardware key that plugs into a USB port on your computer or into your keyport The HASP is small measuring 3 8 x 1 3 cm 1 5 x 0 5 in and is your license to the software Replacements are not free GPS customers will find their HASPs attached to the geodesic dome The HASP must remain plugged in and illuminated when you e use Net Station e generate a HASP file to request a license update e download the modified HASP file from EGI to update your license For detailed instructions about updating the HASP see Appendix B Updating EGI Licenses Software Installation You can install Photogrammetry directly from the CD Double click on the Net Station Installer and follow the onscreen instructions If you are installing this software on a computer containing an earlier version of Net Station contact support egi com to have your license updated File Organization The Net Station Application Program Package contains many files that cannot be accessed by the user Thes
75. amera triad is 1 2 3 Click the forward button of the Navigation tool described in 4 Navigation tool on page 121 to make the next triad appear 1 3 4 or click in the triangular space between cameras in the camera dome Occasionally you may want to select nonadjacent cameras manually because the lines of sight in 3D are better You can select these cameras using the camera pop up menus above the camera views 120 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling Figure 8 11 shows the 3 Up Model window bamar BOLL om MS L Ji GOl ole Click the 3 Up 3 button middle to view camera triads a le Figure 8 11 3 Up Model window The following are brief descriptions of or references for the numbered items from Figure 8 11 1 Camera view buttons Described in 1 Camera view buttons on page 119 2 Identify Sensors button Described in 2 Identify Sensors button on page 119 3 Update Model button Described in 3 Update Model button on page 119 4 Navigation tool Consists of a dynamic graphical representation of the GPS dome and forward and backward buttons Figure 8 12 This tool is visible in 1 Up and 3 Up Acquisition and Model windows It is not visible in any All Up modes GPS dome highlights in color the currently selected camera or camera triads in the 1 Up or 3 Up windows respectively To navigat
76. an project lines from the camera image planes to the sensors on the head surface precisely allowing it to solve for the sensor positions Calibration is typically required only once right after system installation However if you reinstall the Net Station software or move the GPS to another room or building the system should be calibrated again This chapter discusses calibration principles calibration specific menus and buttons and step by step calibration instructions If you have difficulty discerning the numbers on the calibration targets when using the camera views see Appendix D Calibration Target Layouts which provides maps of the calibration targets visible from each of the 11 camera views Calibration Principles The GPS uses 11 cameras to acquire sensor images The camera lenses have very low radial distortion typically less than one pixel over the field of view The camera model is defined by 11 radial parameters camera location radius theta and phi camera angle theta phi and rotation pixel scale and pixel aspect ratio and other camera variables focal length u offset and v offset The Calibration Object supplied with the GPS is a precisely manufactured sphere with a threaded opening at its base The Calibration Object measures 10 91 cm 4 3 in in radius approximately the size of a human head The calibration targets are Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November
77. analyzing the electrical activity of the brain elastomer Any of various polymers having the elastic properties of natural rubber E focal length The distance from the surface of a lens or mirror to its focal point G gantry One of the two main hardware components of the GPS the other being the dome The motorized steel gantry supports the dome It is hinged to allow for subject entry and exit and its motorized control lowers and raises the dome to accommodate various subject heights geodesic The shortest distance between two points on the surface of a sphere Geodesic Photogrammetry System Technical Manual Geodesic Photogrammetry System EGI s sensor registration system consisting of a geodesic based dome with cameras mounted in its vertices for image acquisition and a Photogrammetry feature for sensor marking and modeling Geodesic Sensor Net EGI s dense sensor array A structure of elastomer lines in the approximation of a geodesic GPS See Geodesic Photogrammetry System GSN See Geodesic Sensor Net H HASP Stands for Hardware Against Software Piracy A hardware based cross platform software copy protection system that prevents unauthorized use of software applications iconize In graphical user interface terms a way to maximize screen space by reversibly causing a window to shrink down to a token that is much smaller than the window icosahedron A polygon having 20 faces inion Pro
78. and main body connection points 39 2 7 Gantry assembly process 40 2 8 Gantry bolt sets at three main connection points 41 2 9 The dome structure with cameras numbered for identification 42 2 10 Gantry and dome connection points 45 2 11 Pipe clamp configurations 46 2 12 Dome assembly process 47 2 13 Connecting the power and the USB cables 48 2 14 GPS connectivities 49 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Ix List of Figures chapter 4 chapter 5 chapter 6 Software Installation 4 1 The Net Station icon 59 Startup and Menus 5 1 5 2 5 3 5 4 5 5 5 6 5 7 5 8 5 9 5 10 5 11 5 12 5 13 5 14 5 15 5 16 5 17 Starting Photogrammetry 61 The Photogrammetry dialog 62 Select Subject window 63 Photogrammetry menu bar 64 Edit menu in the 1 Up Model window 65 View menu 66 View gt Info Window gt General 67 OK to Revert dialog 68 View gt Info Window gt Calibration 68 View gt Info Window gt Log 69 View gt Compare Nets 69 Actions menu 70 Net Station menu 70 File menu 71 Docs menu 72 Tools menu 72 GPS file icon 73 Camera Calibration 6 1 6 2 6 3 6 4 6 5 6 6 6 7 6 8 6 9 6 10 The GPS Calibration Object separate from its stand left and outside the dome right 76 Calibration process 77 Overview of positioning the Calibration Object for image acquisition 78 Expanded view of Steps 1 3 in positioning the Calibration
79. ation file and to apply the correct calibration values to the current GPS file Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 91 6 Camera Calibration 92 Figure 6 16 shows the file selection dialog that appears after you click the Assign Calibration button From g Photogrammetry files E photogLOF backup fm photogLOF fm photogLOT backup fm E photogLOT fm t hotog IOL tm prerace pnotog Paea 3 Photogrammetry files p photogTOC backup fm a r y Cal B4ship_ic good points T goodtom S goodtom_card goodtom_card2 goodtom_card3 goodtom_markedall goodtom_markedall2 Heatherl111 a Heathe LLLI mors sfo y lt Add to Favorites X 4 X z Cancel 3 Ope Figure 6 16 File selection dialog The Calibration Files When the system is calibrated it creates two files one on the hard drive called the Precise Camera Description file and the other in a user selected folder called the calibration file Precise Camera Description File You will never work with the Precise Camera Description file but for completeness this section describes it briefly The Photogrammetry software stores the Precise Camera Description file in the Net Station Application Program Package folder Because the file is tagged with the GPS serial number whenever you use that same GPS dome to acquire images the Photogrammetry software will
80. ats of the export files and other files associated with Net Station These publications contain a good deal of background information on the EEG field However they are not intended to represent a complete primer To get the most out of these books you should have some background in EEG methods The manuals assume familiarity with the Macintosh computer the platform for Net Station Note Net Station does not support Unicode string About This Manual This manual the Geodesic Photogrammetry System Technical Manual covers both the hardware and software aspects of the GPS It documents the concepts underlying the system installation requirements and procedures and all software menus windows dialogs and features The manual also describes the operating procedures for image acquisition sensor marking and editing and data export Features This manual is supplied as a PDF file and in printed form The hard copy version has been printed from the PDF so the content of both will match The hard copy manual contains mostly grayscale images the PDF contains color and grayscale images Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 XIX Preface Manual Organization This manual features a table of contents list of figures list of tables and index which in the PDF are all hyperlinked to the topics they reference in the manual The chapters fall into two main categories e Backgrou
81. chnical Manual S MAN 200 GPSR 001 e November 22 2006 193 194 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 EGI 1600 Millrace Drive Suite 307 Eugene OR 97403 1995 USA 1 541 687 7962 tel 1 541 687 7963 fax www egi com
82. d points use camera overlays camera filters and other tools to solve unsolved points and click Update to modify the 3D Point Cloud Export data for use in third party applications such as BESA or EMSE Figure 1 2 GPS operational overview 28 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 1 System Overview If the sensors become disarranged during the EEG session the Compare Nets feature enables you to measure the amount of sensor displacement Just repeat the image acquisition and sensor modeling process illustrated in Figure 1 2 and choose View gt Compare Nets The Compare Nets feature is described in Chapter 10 Note In most cases comparing Nets should be unnecessary The exceptions are time intensive experiments such as sleep studies Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 27 1 System Overview 30 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 2 HARDWARE ASSEMBLY he Geodesic Photogrammetry System is designed for easy assembly The main hardware consists of the geodesic dome and the motorized gantry Figure 2 1 Other hardware includes the data acquisition computer and monitor This chapter discusses the environmental operating conditions site requirements equipment symbols and labels hardware components and assembly procedures for the dome and gant
83. dinal point locations Further solutions supply additional information to fit the EGI Head Model at more points 3D Point Cloud Figure 8 16 shows the 3D Point Cloud overlay HeatherCompletelysolved 3D Point Camera 1 z pri utton o G ai a 4 g 9 d a G39 Point Cloud 5 applied 8 S y 5 n a 23 k i ta a 6 a a e t v x a ba Oo i t 6 4 z g b Figure 8 16 The 3D Point Cloud overlay Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 127 8 Sensor Modeling When you click the 3D Point Cloud button the software projects the Point Cloud defined in 3D space back onto the 2D images The 3D Point Cloud is displayed in orange type The purpose of this overlay is to allow you to compare the 2D User marks with the Point Cloud points providing a general idea of the accuracy of your sensor modeling view the numbers by clicking the Numbers button The 3D Point Cloud is best as a reference confirming the general placement of the User marks Numbers Figure 8 17 shows the Numbers overlay HeatherCompletelysolved x _ Numbers Camerata ad SSS i 105 118 143 88 87 486 1247 x6 LO6 N b umpers 3 4 81 80 aa i i i applied F i L07 5 Tf E 62 68 sb 7 ei of ey 54 5I 19 50 a a k eal 38 23 24 S f 30 652 29 wai 43 30 42 Figure 8 17 Numbers applied to a model When you click the Numbers button t
84. dix D Calibration Target Layouts on page 173 82 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 m e Photogrammetry tbh nby Het hie Colin Oh Mirren CaM feet OT fiemgar af janiai 14 Pearce Pagi 0 09 DA unter Ioan f Cier ages d Oper Pili 4 Wastin Ob Died 1 Click the Open Dataset to open the Model window for the acquired calibration image set or open the file using standard tile opening methods 4 Inthe camera view double click on the dot in the middle of the calibration target to open the Change Number dialog 6b Ifthe mark is not correctly marked you can edit it by e Deleting press the Shift key and move the cursor over the point until you see the delete symbol click to remove the point e Moving move the cursor over the point until you see the move symbol 0 drag the mark to the new location e Renumbering double click on the mark to open the Change Number dialog and type in the correct number To undo an edit press Command z Geodesic Photogrammetry System Technical Manual 2 Inthe Model window click the 1 Up button to view the image from camera 1 Change Number ey ey 5 In the Change Number dialog type in the correct number and click Change 7 Go to the next camera view by clicking the Navigation forward button e clicking on camera 2 in the dome diagram or e choosing camera 2 from the camera pop up men
85. dows it is not visible in any All Up modes 11 Camera filters Described in Camera Filters on page 124 12 Camera overlays Described in Camera Overlays on page 125 13 Camera view Described in 5 Camera view on page 119 14 Task indicator Described in 7 Task indicator on page 120 122 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling 1 Up Window The 1 Up window provides the closest view of an image captured by one camera with a maximum scale of 1 1 Use this window during sensor marking and modeling for placing User marks precisely Figure 8 13 shows the 1 Up Model window g Heather1111 2 o i pn Click the 1 Up U amp 3 button leftmost for the closest view CON OU O 10 11 12 ied Cardenal Poirs Weron Ligi Figure 8 13 1 Up Model window The following are references for or brief descriptions of the numbered items from Figure 8 13 1 Camera view buttons Described in 1 Camera view buttons on page 119 2 Identify Sensors button Described in 2 Identify Sensors button on page 119 3 Update Model button Described in 3 Update Model button on page 119 4 Navigation tool Described in 4 Navigation tool on page 121 5 Mode indicator Described in 4 Mode indicator on page 120 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001
86. dware components 34 49 how to open file 73 how to start 61 intended use 23 labels and symbols 33 operational theory 24 site requirements 32 GPS camera structure 101 GPS computer 49 GPS connectivities 49 GPS monitor 49 GPS Number indicator 63 GPS package contents 57 H hardware components 34 49 Identify Sensors button 119 image acquisition principles 95 Info Window Calibration 68 General 67 L labels and symbols 33 M Mode indicator 120 Model Images window Camera view 120 Camera view buttons 119 Fiducial buttons 122 Identify button 119 Mode indicator 120 Model view 122 Model view controls 122 Task indicator 120 Update button 119 Model view 122 Model view controls 122 130 Navigation tool forward and backward buttons 101 122 GPS camera structure 101 Net Size pop up menu 63 Number of Sensors indicator 63 O Observations window 66 Open Dataset button 64 P Pedestal Height indicator 63 Photogrammetry dialog 62 Photogrammetry menu bar 70 preauricular point 137 S sensor layouts 179 sensor modeling marking and editing instructions 110 site requirements 32 software installation 58 system requirements 57 192 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 T Task indicator 120 3D Point Cloud Projection 127 Tools menu 72 Photogrammetry command 72 U Update Model button 119 V View menu 66 Geodesic Photogrammetry System Te
87. e number of E5 1 32193 A 41155 7 88824 8 129 E 6 45084 2 73199 5 58143 Fiducials Nasion LPA E7 2 P 166 4 91524 9 21277 ar 8 82115 6 85655 ES 4 45548 8 19947 2 50865 ar 6 05036 E9 3 30597 6 560344 8 122748 ar 6 55431 6 61268 E18 2 24530 5 20007 2 93882 5 ice E14 0 326985 3 61427 5 40079 a REF E12 2 14194 0 23268 6 93492 be 0 12042 6 099015 E13 3 30317 2 54309 7 95793 a 466 E14 2 086895 8 75499 2 13761 T at 1 E15 1 03952 7 10656 0 41747 F 6 03176 8 62558 6 67656 os Figure 9 4 An example BESA export file left and EMSE exp amp Heatherl111_emse elp a 2 Sensors RPA 6 04251 6 81164 6 83981 6 04251 4 15383 ai ay Aa ort file right Consult the manufacturer s manuals about how to use the exported data in either EMSE or BESA 140 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 10 COMPARE NETS P hotogrammetry s Compare Nets menu command allows you to compare the positions of sensors of the same Net registered at different times Some example applications may include e To account for sensor displacement which may occur during long EEG exams or experiments such as sleep studies e To provide an additional means of quantifying study results by allowing you to specify in your published work the amount of sensor displacement that occurred during the experiment This chapter describes the Compare Nets princ
88. e File menu Figure 5 14 contains standard commands for working with Net Station files The most important in Photogrammetry are Open Export and Find File i Does not allow you to create a new GPS ____ Nev Y file to do this use the Photogrammetry dialog see Figure 5 2 on page 62 Close W Save S Save As Find File 3 amp F Page Setup Print 3 amp P Figure 5 14 File menu e Open displays the Net Station Open window which allows you to locate and open files of various Net Station formats including Photogrammetry e Export allows you to rename and save the GPS file as either a BESA SFP file or an EMSE Elp file e Find File displays a window that allows you to specify the parameters of your file search primarily location and search term for example name or kind including Photogrammetry or subject ID Note Printing is unavailable from the File menu however you can save Photogrammetry windows as screen shots or TIFF files and print them in that format For details see Chapter 11 Printing GPS Images Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 7 5 Startup and Menus Docs Menu The Docs menu Figure 5 15 allows you to organize your screen space For a full description of all the menu commands see Chapter 4 Menus of the Net Station Viewer Technical Manual lconize v good points Figure 5 15 Docs menu Tools Menu
89. e November 22 2006 123 8 Sensor Modeling 6 Fiducial buttons Described in 6 Fiducial buttons on page 122 7 Number control Described in 7 Number labeler on page 122 8 Camera pop up menu Described in 10 Camera pop up menu on page 122 Also allows selection of the model view with its associated controls see Model View on page 129 and Model View Controls on page 130 9 Camera filters Described in Camera Filters on page 124 10 Camera overlays Described in Camera Overlays on page 125 11 Camera view Described in 5 Camera view on page 119 12 Task indicator Described in 7 Task indicator on page 120 Additional Window Tools The Model window provides additional tools to help solve the model points camera filters camera overlays and the model view Camera Filters These tools allow you to lay different filters over the camera views The filters highlight different features in the pictures making it easier to check the positions or identities of the User marks The filters are Normal Onion Skin and Inverse see Figure 8 14 apply each view by clicking on its corresponding button 124 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling You can apply filters in the 1 Up or 3 Up window To apply a filter to all the camera views in the 3 Up window simultaneously Command click on the filter b
90. e as reference points for integrating your GPS data with BESA or EMSE Note You can mark the fiducial points at any time during the sensor modeling process not just before data export This chapter describes the export principles and provides step by step instructions Export Principles Fiducial points are reference points or landmarks that enable you to integrate data generated by different image modalities e g integrating EEG with MRI Photogrammetry uses four fiducials the vertex nasion left preauricular point Lpa and the right preauricular point Rpa the preauricular points are the indentations just in front of the ear flaps where the jaw meets the skull as shown in Figure 9 1 Vertex and Cz beneath sensor 7 129 ina 128 channel GSN 200 Rpa lt Preauricular nN point Nasion beneath sensor 17 in a 128 channel GSN 200 SN e W 1 ot i k k Gray s Anatomy Figure 9 1 Skull landmarks Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 137 9 Data Export However you cannot place a point directly over an existing point and the nasion and vertex are located underneath two points Fortunately their positions are already marked in the GSN sensor map e g as sensors 17 and 129 in a 128 channel GSN 200 This means that in most cases you will need to mark only the left and right preauricular points One rare exception is if th
91. e dome 6o PRoatogr amma try F eine ian Mime CaM aft CiT femgar at janiai 14 Pearce Pga 0 09 4 Inthe Photogrammetry dialog click the Capture Images button to initiate system connection with the cameras a 1 Up ay button Me le 7 Click the 1 Up button and cycle through each camera view inspecting the Calibration Object closely If a red tint covers a camera view see Red Tints on page 82 hemgar af bentari 14 Pedra pegha 0 09 GA iunte foo Cipre FIH 4 OF ppap 2 Open the Photogrammetry dialog choose Calibration Object from the Net Size pop up menu in the Photogrammetry dialog and click the New button 5 When connected the 3 Up window appears displaying video from cameras 1 2 and 3 If the unable to acquire message appears go to Retry Initialization on page 87 8 Click the 3 Up button and cycle through each camera triad verifying that difficult to see targets those on the underside are seen by at least two cameras when satisfied click the Take Pictures button New PhotogrammatryReconding Sarit A3 antiehed j Where ij Seasions H l i r 7 3 In the New Photogrammetry Recording dialog that appears specify a name and destination folder and click New 6 Click the All Up button and verity that each camera target is facing its respective camera and that the Calibration Object is fully visible in each camera and is centered 9 Revie
92. e head shape is unusual and the nasion and vertex sensors do not quite sit on those skull landmarks even though the Net is properly applied In this case you may want to mark the nasion and vertex in addition to the preauricular points Table 9 1 shows the cameras and the fiducial points typically in view a top down view of the dome shows the points in relation to the geodesic structure In brief the Rpa is typically visible in camera views 3 7 and 8 the Lpa in views 6 10 and 11 Table 9 1 Fiducial points per camera view Camera Fiducial point Camera map top view nose up vertex 2 nasion vertex 3 Rpa vertex 4 vertex 5 vertex 6 Lpa vertex 7 nasion Rpa 8 Rpa 9 vertex 10 Lpa 1 nasion Lpa j O fiducial camera 138 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 9 Data Export Figure 9 2 provides a flowchart of the export process Open the image file and click the 1 Up or 3 Up button Y Select the Lpa button and in each image click where the left When finished marking the Lpa in 2 images is fine repeat the process for the right preauricular point Rpa When finished click the Update button Choose File gt Export and select the preauricular point is visible a yellow LPA marks each click export format output file name and output destination Figure 9 2 Export process
93. e include the files that contain the system calibration and head modeling values for Photogrammetry Brief descriptions of these files are provided here to facilitate understanding of how GPS works Caution If you inadvertently open the Net Station Application Program Package be sure not to move rename or delete any item Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 A Software Installation During software installation the Net Station application is saved to the Applications folder on the hard drive The Net Station folder contains the Net Station icon and the Extras folder The application also installs two types of Photogrammetry specific files the EGI Head Models and the Precise Camera Description file Photogrammetry automatically accesses these two file types while you proceed with your sensor registration work The EGI Head Models serve as the starting points for the 3D modeling performed using the Photogrammetry module The EGI Head Models which are averaged 3D models developed by EGI are based on numerous measurements of subjects of various head shapes and sizes wearing the Geodesic Sensor Net While you work further with Photogrammetry the models change until they closely resemble the real subjects head shapes and sizes The Precise Camera Description file is created when you calibrate the cameras discussed in Chapter 6 The file contains values that define the system s ca
94. e to specific cameras click on Figure 8 12 Navigation tool individual cameras or in the space between triads Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 121 8 Sensor Modeling Forward and backward buttons cycle through single camera selection in numerical order in 1 Up mode or through camera triads in 3 Up mode 5 Mode indicator Described in 4 Mode indicator on page 120 6 Fiducial buttons Represent the following fiducial or landmark marks vertex Fiducial buttons Cz nasion Nas left preauricular Lpa and right preauricular Rpa As aminimum you must mark the left and right preauricular points in all images in which they appear before using the Compare Nets menu command or exporting the data For details see Chapter 9 Data Export and Chapter 10 Compare Nets faa Pp 7 Number labeler Allows you to assign numbers manually Click the checkbox to activate the labeling function to change the number in the labeler box click an arrow button press Command arrow key or swipe and type and click on a point in a camera view Number labeler 8 Model view Described in Model View on page 129 9 Model view controls Described in Model View Controls on page 130 10 Camera pop up menu Displays the current camera and allows manual selection of another camera 1 through 11 This menu is visible in 1 Up and 3 Up Acquisition and Model win
95. ed to work seamlessly with EGI s Geodesic Sensor Net sensor array and Net Station software so you can go from GSN application GPS image acquisition and Net Station Photogrammetry marking editing and exporting of sensor data effortlessly e Repeatable and reversible registration The GPS displays your marks on the acquired images onscreen allowing you to see obvious user errors quickly You can correct your mistakes immediately and continue marking the points Later you can review the marks and correct them as needed If necessary you can even erase all your work and start from the beginning The GPS is flexible enough to accommodate users with a wide range of experience and skills 148 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 12 GPS FAQs What are the general steps to registering sensor positions with the GPS Assuming that the system has been correctly calibrated the steps are 1 Position subject wearing a GSN within the GPS dome 2 Acquire images of the subject ensuring that he or she is centered in each of the 11 camera views 3 Mark and edit the visible cardinal points in each of the 11 camera views until the points are identified and solved Note If you wish to export the cardinal point solution proceed to Step 5 4 Mark and edit the visible non cardinal points in each of the 11 camera views until the points are identified and solved 5 Mark the
96. ent contrast Cardinal mode Incorrect number of cardinal After you clicked the Identify button in points Please re check cardinal mode the software did not point locations and try again come up with the correct number of or solve manually if cardinal points Check for extra points necessary add more points and try again make sure you have a valid Calibration Object or click the Revert to Saved button in the Info Window and try again Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 12 GPS FAQs Category Cardinal mode Table 12 1 GPS error messages Message There are not enough points selected to identify the cardinal points for this net Please select more sensors Solution You must have at least twice as many User marks as you have cardinal points before attempting to identify Add some more User marks Cardinal mode Non cardinal mode All cardinal points need to be solved before you can continue You must solve the cardinal points before you can solve the non cardinal points You have not solved all the cardinal points Check the Sensor Locations window and determine which cardinal points are missing Mark and model them as needed You are trying to solve in non cardinal mode before you have selected and solved the cardinal points Stop make sure the mode indicator is set to Cardinal Mode mark the cardinal points click
97. f the appropriate sensor layout readily at hand for reference Note Sensor layouts are particularly useful when marking the cardinal points in an HCGSN The cardinal points in the HCGSNs are colored red however some HCGSNs contain sensors with red pedestals that are NOT cardinal points Refer to the sensor layout for the correct cardinal points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 109 8 Sensor Modeling Cardinal Point Instructions Figure 8 3 provides an overview of how to mark and edit cardinal points Figures 8 4 8 5 and 8 6 provide expanded views of the steps 1 Using the GSN s sensor layout as a guide mark the cardinal points in camera view 1 the average number of cardinal points visible in each camera view is 3 Incorrect namber of cardinal points please re Pa check pointe locations and try again or toha fa marisally if eecensary 4 lf an error message appears you must edit the unsolved or questionable User marks If no error message appears you may still need to solve any remaining unsolved points before exporting the cardinal point solution or marking the non cardinal points 00a Sensor Locations Carya staa BiH Ea derse C Dpp apit 9 T1 m TITA 4301 0 203 i EFFI Jaaa 0d 7 t LEER GIO RHE 18150 Laji ii l PAGH I7AR 4749 Io DDZ 4231 943 THO iari Gh p GB GG TIN CETE ME AEE Far Io BFE BD ae Pare 6 50 aaia
98. for Calibration Version 1 0b4 Figure 5 5 Edit menu in the 1 Up Model window e Clear removes all User marks from the image This is useful if you have incorrectly marked points in the currently displayed image and wish to start over Note To clear User marks from all images choose View gt File Info gt General and click the Revert to Start button for more information see Info Window on page 67 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 65 5 Startup and Menus View Menu The View menu allows you to view the data in a GPS file in many different ways via views modeling tools the Info Window and the Compare Nets feature Figure 5 6 shows the View menu 1 Up 3 Up 38 3 All Images FA Model Observations Modeling tools Sensor Locations Info Window 36 Views Compare Nets Figure 5 6 View menu View Options The Views options duplicate selected controls in the Acquisition and Model windows e 1 Up accesses the 1 Up mode see page 103 for the 1 Up Acquisition window and page 126 for the 1 Up Model window e 3 Up accesses the 3 Up mode see page 99 for the 3 Up Acquisition window and page 123 for the 3 Up Model window e All Images accesses the All Up mode see page 101 for the All Up Acquisition window and page 121 for the All Up Model window e Model accesses the Model view see Model View on page 133 Modeling
99. g from the list of solved cardinal points 3 8 15 6 449 6 428 a for a 256 channel HCGSN 4 953 7 152 7 937 2 744 6 573 2 572 os i We know that 31 is missing because we ae ae compared the solved cardinal points in the 6 489 4 626 2 464 Sensor Locations window with the list of 3 2 10 9 288 4 836 cardinal points for a 256 channel HCGSN 6 002 6 805 3 244 see Table 8 1 on 109 or Figure E 9 on 9 543 1 482 5 572 page 196 2 841 6 961 0 964 4 821 3 775 9 199 6 045 3 7 66 4 890 2 120 9 662 3 185 8 406 3 669 2 735 Figure 8 5 Expanded view of Steps 4 6 in marking and editing cardinal points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling eee Sensor Locations 7 Click on the Number column and on the sort PREBE Cameras sowed RMS Coordinate 2 toggle to sort the results by number scroll down to 27 0 000 8 540 2 960 7 182 31 which has been marked in only one camera 28 0 000 7 329 4 301 8 243 D view camera 2 29 0 000 5 751 5 489 9 035 30 0 000 3 690 6 710 9 246 31 0 000 10 130 1 439 2 848 A point may be unsolved because it is marked 0 000 9 865 2 788 4 249 z gt ii in too many camera views In this case follow 33 0 000 9 002 4 231 5 543 ee TT Steps 8 9 but instead of adding User marks 35 0 000 6 531 6 530 7 214 _ delete them as necessary Only two User marks 36 SOE ST
100. g the sensor layout for guidance as needed c choose View gt Sensor Locations d manually mark unsolved points as solved in the Sensor Locations window and e click the Identify Sensors button Repeat this process until no error message appears which indicates that the cardinal set has been identified Even when the cardinal set is identified some unsolved points may remain in the data set You must solve these remaining unsolved points using the steps just described and click the Update Model button After all points are solved save a copy of the solved file Note For more information see Tips on Editing the Cardinal Points on page 114 Once the cardinal points are successfully identified you can export the data or mark the other sensors Exporting after the cardinal stage results in a partially solved data set containing estimated positions of the non cardinal points To mark the other sensors 1 Mark the non cardinal points in each of the 11 views Do NOT touch the cardinal points Save a copy of the marked up file 2 Follow Step 2 in the preceding section with one exception after clicking the Identify Sensors button the set is considered identified even if many sensors are considered unsolved or questionable Therefore any edits made 106 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling
101. he edges appear smooth not jagged 2 In terms of EEG this is the filtering of a signal before digitization so that high frequency components do not appear as false lower frequency components azimuth The horizontal angular distance from a reference direction usually measured clockwise from due north to the point where a vertical circle through a celestial body intersects the horizon C calibration The act of checking or adjusting the graduations of a quantitative measuring instrument cardinal point A sensor that is of foremost importance paramount In the GPS the cardinal points are 10 11 well spaced sensors that help establish general Geodesic Sensor Net orientation coregistration The process of lining up two images covering the same area in a way so that they fit exactly on top of each other D dense sensor array Any sensor system that supports a sufficient number of sensors to spatially sample a phenomenon adequately For EEG recording this generally means 64 channels or more digitization The process of putting data into digital form S MAN 200 GPSR 001 November 22 2006 187 Glossary 188 dome One of the two main hardware components of the GPS the other being the gantry The aluminum dome is in the shape of an icosahedron with the bottom omitted A camera is mounted in each of the 11 vertices EEG See electroencephalography electroencephalography The science of recording and
102. he software projects ID numbers onto the acquired images The numbers correspond to the User marks and any model overlays applied to the images When points in the overlay and the User marks are physically very close the Numbers overlay displays one number to save space 128 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling Model View The model view is visible in the 3 Up Model window and can be selected from the camera pop up menu in the 1 Up Model window The model in the view is an interactive 3D representation of the 2D User marks When you change a mark in a 2D image and click Update the model in the view also updates Model View Purpose The model view allows you to detect poorly spaced points the geodesic tesselation ensures even spacing between points or jagged outlines indicating that sensor positions need editing This view also provides feedback about changes made to sensor locations IDs or both The model view represents cardinal points in blue fiducials in yellow other solved points in bright green unsolved points in khaki green and EGI Head Model points in gray not all are represented in Figure 8 18 eo 8 Heather ena B 4 en lies om es ee gee K 0 o o o o e mi p Q o ee Model Or ct tats view e e6 Model view controls ET AET Figure 8 18 The model view in the 1 Up camera view
103. he streaming video of the subject in the dome The subject s head should be centered in all camera views adjust the dome height or subject s position as necessary e Carefully review the images before accepting them Figure 7 1 provides a flowchart of the acquisition process Open the Photogrammetry dialog and select the correct Net size Y Click the New In the dialog click Capture button name the Images which opens the Is the subject positioned well file and save it Acquisition window Reposition the subject so that he or she is facing camera 2 Make sure that all 11 images have a complete view of the head with no part cut off No Are the images good Click the Take Pictures button in the Modeling window Yes Click the Accept Pictures button Figure 7 1 Acquisition process 96 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Reminder A good Net application improves the sensor registration results So make sure the cardinal points are colored the preauricular points are marked the sensors are evenly spaced and the wires are not obscuring the pedestals Geodesic Photogrammetry System Technical Manual Before Image Acquisition 7 Image Acquisition The accuracy of the sensor registration depends in some measure on the application of the GSN to the subject s head Therefore before acquiring images remember to e
104. ible The model view will display only the current Net For information about other Photogrammetry error messages see Photogrammetry Error Messages on page 156 5 Model view controls Described in Model View Controls on page 134 6 Net model color Indicates the color of the file s 3D Point Cloud in the model view 7 RMS error indicator Calculates and displays the average RMS error of the current GPS file compared with the second GPS file The error is calculated in 3D space in units of centimeters Note This RMS error differs from the RMS error calculated during the sensor modeling process which is calculated in 2D space and in units of pixels Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 143 10 Compare Nets Compare Nets Instructions 1 After the exam or experiment register the sensors again following the instructions in Chapter 7 Image Acquisition and Chapter 8 Sensor Modeling 2 In both the pre and post exam GPS files mark and save the fiducials following the instructions in Chapter 9 Data Export but do not export the data 3 Open one of the GPS files and choose View gt Compare Nets 4 Inthe file selector of the Net Comparison window select the other GPS file by either dragging it to the file selector window or clicking the Select button and navigating to it 5 The window automatically compares the two files and displays three items
105. ientation 3 1416 e 1 3129 Phi Orientation 3 1416 f 16 3784 Rotation Orientation 3 2216 g 4 6046 Focal Length 0 6162 h 230 2300 u Offset 374 3120 i 0 0000 v Offset 230 2300 E 0 0000 k 0 0200 r x r Assign Calibration y Figure 5 9 View gt Info Window gt Calibration 68 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 5 Startup and Menus e Log Displays a history of the operations performed by Net Station on the file This is not a log of user operations Figure 5 10 shows the Log pane eee calib 2004Sep02_Ic Info General Calibration Log f ClearLog Netsolve rms error 0 00000 4 Worst rms by point is 0 00000 0 Located at 1 Netsolve rms error 14 14885 Worst rms by point is 52 03845 Located at 9 Center 0 00000 0 00000 0 00000 0 00000 RMS Error 15 15757 sphering distance 1 71379 sphering factor 0 96818 Center 0 00000 0 00000 0 00000 RMS Error 15 28219 sphering distance 1 76747 sphering factor 0 96763 40 Figure 5 10 View gt Info Window gt Log Clear Log button deletes the list of operations from the window Compare Nets The Compare Nets command opens the Net Comparison window which allows you to compare the GPS files of a subject before and after an EEG session for sensor displacement For a full description see Chapter 10 Compare Nets 8oe Met Companison Select the other GPS file for
106. ing and numbering all the points is more prone to error than using the Photogrammetry software as it is designed So be patient and keep practicing preferably with a copy of an acquired image set It click the Identify Sensors button and no error message appears can automatically go to the next step No An identified set can contain unsolved points this is most likely to occur during the non cardinal mode Identified only means that the software was able to assign numbers to the User marks the software may still be unsure about some of the points You must choose View gt Sensor Locations and solve the unsolved points and edit the User marks of those points before proceeding to the next step Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 12 GPS FAQs Are there some precise steps can follow to model my points Not yet We can however provide the following guidelines e More is not always better A point must be marked in at least two camera views for the software to triangulate its position three is ideal But if you ve marked the point in many camera views delete some of the marks More marks often means more chances for error e Know your Net Knowing the numbering scheme of your GSN will make solving the unsolved sensors much easier Consult the appropriate sensor layout or apply the EGI Head Model overlay for the correct numbers e Ret
107. iples and window and provides step by step instructions on how to use this feature Compare Nets Principles The Compare Nets menu command opens the Net Comparison window which enables you to compare the positions of GSN sensors before and after an EEG data acquisition session After the exam you reacquire images of the subject wearing the Net re mark and re edit the sensors and produce a second GPS file for that individual From within that file choose View gt Compare Nets and select the subject s pre exam GPS file The software compares each sensor with its corresponding sensor derives the difference in distance between each pair of 3D coordinates and calculates the RMS error of the current GPS file in 3D space and in units of centimeters The model view represents the point pairs with a bicolor model When used for correcting sensor displacement during a long EEG session the post exam data can often provide a more feasible sensor position than the one registered Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 14 10 Compare Nets before the exam In theory this kind of displacement typically occurs early in an experiment while the subject is settling in and the EEG data collected will more accurately correspond to the second sensor position If a sensor has moved too much you can also make a note to disregard its data during analysis Net Comparison Window To open the Net
108. is a good idea to save a copy of the GPS file after e marking all the points in both cardinal and non cardinal modes and e identifying the data sets in both cardinal and non cardinal modes Saving a copy of a marked up or identified file is useful if you wish to redo the most recent sensor editing but not the previous marking or identifying Cardinal Points Cardinal points are a small number of sensors 6 11 that are evenly distributed throughout a Geodesic Sensor Net In Photogrammetry these sensors serve as control points and anchor the process of calculating 3D coordinates Table 8 1 lists the cardinal points for the adult GSN 200 and the adult HCGSN Table 8 1 Cardinal points for the GSN 200s and the HCGSNs Number of sensors GSN model Cardinal points between cardinal points 32 channel HCGCN 3 4 18 21 22 25 26 33 Ref varies see page 180 64 channel GSN 200 10 13 23 25 35 38 50 59 62 65 Ref 2 64 channel HCGSN 12 26 36 46 60 65 Ref 3 128 channel GSN 200 17 25 44 48 69 73 95 99 120 124 129 Ref 3 128 channel HCGSN 17 24 43 47 68 72 94 98 120 124 129 Ref 3 256 channel GSN 200 30 35 66 71 115 120 169 174 221 226 257 Ref 4 256 channel HCGSN 31 36 67 72 114 119 165 173 219 224 257 Ref 4 Appendix E provides sensor maps of these GSN models with their cardinal points circled When marking and editing sensors keep a copy o
109. isplay time O Antialiasing smooths model edges for a more polished graphic requires additional display time 130 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling Other Modeling Tools From the Model window you can access two modeling tools from the Photogrammetry menu bar the Observations window and the Sensor Locations window Observations Window Choose View gt Observations to open the Observations window which displays information about each 2D User mark in all the images After the 3D model is solved the Observations window identifies the true ID number for each observation Changes made in this window propagate to the camera views but not to the Sensor Locations window To propagate changes to the Sensor Locations window manually click the Update Model button in the Model window Figure 8 19 shows the Observations window 1 2 3 4 To open choose Views gt Observations l 124 0 l 2 25 G l 3 129 E 1l 4 11 Ke 1 5 4 e 4 l 6 5 e Delete Mark Solved 7 6 7 Figure 8 19 Observations window Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 131 8 Sensor Modeling The following are brief descriptions of the numbered items from Figure 8 19 1 Camera column Indicates the camera in which the point is marked Click on the column header to sort the data by camera 2 Point
110. ition and sensor modeling Figure P 1 The geodesic dome photographs the subject wearing a GSN and that s all the subject time needed for sensor registration At some convenient time you mark the sensors digitally using the Photogrammetry feature by clicking on the tops of the sensor pedestals visible in the photos You can view and edit your work as you go Use the GPS to photograph a Mark sensors on photographs in subject wearing a GSN Net Station and model them to determine their 3D coordinates Figure P 1 Image acquisition and sensor modeling Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 xvii Preface XVIII Hardware related e The Geodesic Photogrammetry System is EGI s icosahedron based structure for acquiring images of subjects wearing Geodesic Sensor Nets and for registering sensor positions in Net Station This manual the Geodesic Photogrammetry System Technical Manual describes all GPS features and functions The Geodesic Sensor Net is EGI s patented dense array device for acquiring electrical signals from the human scalp The Geodesic Sensor Net Technical Manual describes all GSN features and functions The GES hardware is all the hardware for the Geodesic EEG Systems except for the GSN GES hardware components support the acquisition and processing of EEG data and include an amplifier data acquisition computer and oftentimes a system cart The GES Hardware
111. leted click the Identify Sensors button to initiate the process of determining the sensors correct ID numbers according to the built in sensor layout and using triangulation to create a 3D model of the GSN 26 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 1 System Overview The software projects those 3D points back through the cameras applying the camera calibration values to them and displays them as points in a 3D Point Cloud model that can be overlaid on the acquired images The differences between the 2D User marks and the 3D Point Cloud marks are the root mean square errors of the solved locations The RMS is measured in centimeters if measuring the RMS for the entire system or for a Compare Nets function which occur in 3D space or pixels if viewing the RMS in the Sensor Locations window which calculates the error in 2D space Point Solution If the software is uncertain about the correct ID numbers of some sensor locations it assigns temporary numbers and labels them as unsolved To solve these points you must renumber them based on the information provided by the GSN sensor layout map and click the Update Model button to propagate the changes to the 3D model Because of the large number of sensor positions that must be solved the GPS requires a two step approach e Mark and solve a subset of sensors in the GSN These sensors called cardinal points are control points
112. marks you should click the Update Model button afterward unless you wish to automatically renumber points or to recalculate the solution set What is the EGI Head Model overlay And the 3D Point Cloud overlay The EGI Head Model overlay is initiated by the T button see left When you click this button the Photogrammetry software overlays the built in EGI Head Model points for the Net model used on your subject onto the acquired images If the Numbers overlay is applied the EGI Head Model overlay allows you to verify that your User marks are correctly numbered because it projects the EGI Head Model points and numbers on top of your User marks EGI Head Model The 3D Point Cloud overlay is initiated by the red comet button see left When you click this button the Photogrammetry software projects the 3D Point Cloud 3D Point Cloud defined in 3D space back onto the 2D images This overlay allows you to compare your 2D User marks with the 3D Point Cloud points so that you can have a general idea of the accuracy of your sensor modeling Why might I need to mark some points as solved manually Given the large number of sensors in a GSN and their proximity to each other in the dense Net structure sometimes the Photogrammetry software marks a point s identification as questionable or unsolved because it cannot provide complete assurance that the point has been correctly numbered or cross correlated In these
113. menu S MAN 200 GPSR 001 e November 22 2006 97 7 Image Acquisition Any difference between the calibration and subject image acquisition processes stems from visibility issues Namely the sensors in a GSN on a subject s head are more difficult to see than the targets on a smooth Calibration Object The next section addresses those issues Positioning the Subject Position the subject so that the GSN is fully visible in all camera views Table 7 1 provides positioning tips Table 7 1 Subject positioning tips In Ensure that Each camera view The lighting glare off the pedestals is minimal if possible Each camera view Three cardinal points are visible if possible This may not be possible for camera views 2 and 7 because of the camera angles Each camera view No pedestals are upturned especially in the back with camera views 8 9 and 10 Camera view 1 The subject is centered Camera views 2 amp 7 Sensors near the top of head are visible Camera views 4 5 9 GSN 200 wires do not overly obscure pedestals Camera views 3 7 8 and Fiducial points preauriculars vertex and nasion are visible 6 10 11 Opposing camera views Subject is as symmetrically positioned as possible 3 amp 6 48 amp 5 7 amp 11 8 amp 10 When adjusting the GPS dome to accommodate the subject s height or position heed the following O WARNING Moving parts are a pinch and crush hazard Keep all clo
114. mera parameters enabling Photogrammetry to rely on only two camera views to produce a 3D point position Starting Net Station To start Net Station double click on its icon on the Finder Desktop If the Net Station icon is on the Dock in Macintosh OS X only a single click is needed Figure 4 1 desktop Dock Figure 4 1 The Net Station icon Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 57 A Software Installation 60 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 5 STARTUP AND MENUS T he Photogrammetry menu bar provides an alternate way to access many of the functions of the Acquisition and Model windows which are described in Chapters 7 and 8 The menu bar also allows access to diagnostic information about the current GPS file This chapter describes the Photogrammetry menu bar and provides general information such as how to start Photogrammetry use the Photogrammetry dialog and open a Photogrammetry file Starting Photogrammetry The Photogrammetry mode is available only to licensed GPS users Figure 5 1 shows how to open the main Photogrammetry dialog Two ways to open the Erie View Actions Photogrammetry dialog enan eT Photogrammetry 1 from the Net Station start up window left and fae he Aes view gt Browse Event Criteria 2 from the Tools menu right Browse Files 3E Browse
115. mmetry dialog click the Capture Images button to initiate system connection with the cameras Number of Sensors 36 Pedestal Height 0 00 GPS Number 20020000 Capture Images Open Dataset Version 1 0a6 5 When connected the 3 Up window appears with video trom cameras 1 2 and 3 If the unable to acquire message appears see Retry Initialization on page 87 a Taraes I soo Lal arin l G 6 Click the All Up button and verify that each camera target is facing its respective camera and that the Calibration Object is fully visible in each camera and is centered Figure 6 5 Expanded view of Steps 4 6 in positioning the Calibration Object for image acquisition 80 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 Camera Calibration eos Cal Erhi OEE com a MOO wie 1 i U p f Take Pictures button 7 Click the 1 Up button and cycle through each camera view inspecting the Calibration Object closely If a red tint covers a camera view go to Red Tints on page 82 Sobret Pisati oe Ciit afore Cai Boke comet AROG eE 8 Click the 3 Up button and cycle through each camera triad verifying that difficult to see targets those on the underside are seen by at least two cameras when satisfied click the Take Pictures button Cal RAthip a MOG Weir Q9 Review the pictures and click the Accept Pictures if satisfied
116. n see Camera Filters on page 127 and Camera Overlays on page 129 The Calibration Pane After calibrating the cameras you can choose Views gt File Info gt Calibration to view the Calibration pane which displays the calibration values for each camera in the system Figure 6 15 shows the Calibration pane 0 9e calib 2004Sep02_lc Info General Log Linear Parameters Radial Parameters a 16 3784 Radius 50 0000 b 1 3129 Theta 0 0000 c 7 4862 Phi 0 0000 d 374 3120 Theta Orientation 3 1416 e 1 3129 Phi Orientation 3 1416 f g h i j 16 3784 Rotation Orientation 3 2216 4 6046 Focal Length 0 6162 230 2300 u Offset 374 3120 0 0000 v Offset 230 2300 0 0000 0 0200 Assign Calibration Figure 6 15 Calibration pane The following are brief descriptions of the numbered items from Figure 6 15 1 Linear and Radial Parameters Express the calibration values for each camera in terms of a formula linear and a 3D position in space radial The radial parameters include camera position camera angle focal length pixel scale pixel aspect ratio and image plane center offsets see Theory on page 25 for more discussion 2 Navigation tool Allows you to view the calibration values for each camera by clicking on the dome diagram or by clicking a Navigation tool forward or backward button 3 Assign Calibration button Click this button to navigate to the corresponding calibr
117. n window If unsuccessful after two or three attempts restart the application to clear the USB connection and retry the Capture Images operation If problems persist contact support egi com 88 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 Camera Calibration RMS Error Is High The system RMS error is calculated in 3D space and measured in units of centimeters A system RMS error of more than 2 0 centimeters produces the RMS error is high message Your system cannot be calibrated until this value is 2 0 or below The RMS or root mean square error is defined as the difference norm between the measured and the projected image coordinates the RMS error is a measure of the consistency between the observed image coordinates Possible causes of high RMS values include e poorly placed marks on calibration targets e misnumbered marks e calibration targets marked only once two marks are needed e calibration targets marked in too many camera views the ideal number is three The next section discusses how to use the Sensor Locations window to lower high RMS values Sensor Locations Window The Sensor Locations window displays 3D information based on estimated or triangulated 3D sensor locations and is useful for solving 3D positions Figure 6 14 shows the Sensor Locations window a detailed description is provided in Sensor Locations Window on page 140 608 Sensor
118. nd and setup O Chapter 1 System Overview describes the system operational theory hardware design and routine operation O Chapter 2 Hardware Assembly describes the hardware components site requirements and assembly procedures O Chapter 3 Safety describes warnings and cautions related to the GPS O Chapter 4 Software Installation provides general information about the software such as system requirements GPS package contents and installation e Operations and windows O Chapter 5 Startup and Menus describes basic GPS controls and tasks including the Photogrammetry dialog and Photogrammetry menu bar and how to open a GPS file O Chapter 6 Camera Calibration describes the procedures for using the supplied Calibration Object to generate the Precise Camera Description file for the GPS O Chapter 7 Image Acquisition describes how to use the Acquisition window to acquire high quality images The chapter also includes detailed descriptions of the window s menus views dialogs and options O Chapter 8 Sensor Modeling describes how to use the Model window to mark sensors on the acquired images The chapter discusses how to fit an approximate model of the Net generate estimates of sensor locations check Net model solutions and edit User marks The chapter also includes detailed descriptions of the window s menus views dialogs and options O Chapter
119. nd centered between the preauricular points In the International 10 20 system Cz is the vertex electrode In an adult size 128 channel GSN electrode 129 is the vertex 190 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 November 22 2006 A Accept Pictures button 102 Acquire Images window 1 Up window 103 123 3 Up window 99 120 Accept Pictures button 102 Camera view 102 Camera view buttons 102 Navigation tool 100 Actions menu 70 Assign Calibration button 91 BESA export option 137 C Calibration file 92 calibration instructions marking and editing targets 82 Calibration pane 91 Assign Calibration button 91 Linear and Radial Parameters calibration principles 75 camera pop up menu 101 camera triad 99 120 camera view filters Inverse 125 Normal 125 Onion Skin 125 Geodesic Photogrammetry System Technical Manual camera view overlays 3D Point Cloud Projection 127 Combined 128 Numbered 128 Camera view modes 11 Up 66 1 Up 66 3 Up 66 Capture Images button 64 Compare Nets 69 Difference window 143 file selector 142 instructions 144 principles 141 RMS error indicator 143 Compare Nets window 142 D data export instructions 139 principles 137 Difference window 143 Docs menu 72 91 Edit menu 65 EMSE export option 137 S MAN 200 GPSR 001 e November 22 2006 191 F Fiducial buttons 122 fiducial points 137 File menu 71 G GPS environmental condition 32 har
120. nd strap bolts To assemble the gantry e carefully remove the main body and rolling base from the crate e lay the main body on its back e remove the bolts washers and nuts from the rolling base e position the rolling base and the main body so that their bolt holes align including those of the internal straps ensuring that the small metal lip at the back of the base lies within the main body and e reattach the bolts washers and nuts Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 November 22 2006 37 2 Hardware Assembly Table 2 6 identifies the bolts nuts and washers Figure 2 6 shows their connection points in the rolling base and main body Table 2 6 Bolts nuts and washers for gantry 38 Label in Position in Item Quantity Figure 2 6 rolling base Photo actual size 3 8 16x2 1 2 bolt 2 B bottom 3 8 16 hex nut 2 B bottom 3 8 flat washer 4 B bottom 1 4 20 x 3 4 bolt 4 A amp C front and strap 1 4 20 hex nut 2 A front 1 4 flat washer 4 A amp C front and strap Figure 2 7 illustrates the gantry assembly process Assembly requires one 1 9 16 end wrench one 1 9 16 socket wrench one 1 7 16 end wrench and one 1 7 16 socket wrench which are not provided Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 2 Hardware Assembly Key A front 1 4 20 bolt B bottom 3 8 16 bolt C strap
121. ng images with the GPS is fast making sensor registration convenient for both the subject and the technician This chapter discusses acquisition principles and references step by step instructions Detailed descriptions of the Acquisition window round out the chapter and begin on page 99 Acquisition Principles Using the GPS to acquire images minimizes the amount of subject time During typical sensor registration procedures the subject must remain still while the technician manually touches each sensor with a pointing device By acquiring still images of the sensors on the subject the GPS obtains the same information in a few minutes making it ideal for active subjects such as children The process of registering each sensor can be postponed because the images are saved to disk and can be opened and edited at any time Acquisition Overview Acquiring images is straightforward e Prepare for acquisition by making sure that the pedestals of the GSN s cardinal points are colored if they are uncolored color them with a permanent marker making sure not to cover the sensor number Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 95 7 Image Acquisition e Apply the GSN carefully to the subject and ensure that the cardinal points and preauricular points are visible e Position the subject in the GPS dome so that he or she is centered in the dome e Click the Capture Images button and view t
122. nge applies Note 2 These guidelines may not apply in all situations Electromagnetic propagation is affected by absorption and reflection from structures objects and people Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 171 C EMC Declarations for GPS 172 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 appendix D CALIBRATION TARGET LAYOUTS This appendix provides target layouts for the Calibration Object Each of the 11 camera views is represented displaying the targets typically visible Use these layouts to help mark or model the calibration targets Figure D 1 Camera view 1 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 173 D Calibration Target Layouts Figure D 2 Camera view 2 Figure D 3 Camera view 3 174 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 D Calibration Target Layouts Figure D 5 Camera view 5 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 175 D Calibration Target Layouts Figure D 6 Camera view 6 Figure D 7 Camera view 7 176 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 D Calibration Target Layouts Figure D 8 Camera view 8 Figure D 9 Camera view 9 Geodesic Photogrammetry System Technical Ma
123. nical Manual S MAN 200 GPSR 001 e November 22 2006 XV List of Tables Appendix C EMC Declarations for GPS C 1 Electromagnetic emissions for GPS 168 C 2 Electromagnetic immunity for GPS 169 C 3 Electromagnetic immunity for non life supporting equipment GPS 170 C 4 Recommended separation distances between portable and mobile RF communications equipment and the GPS 171 Appendix E Sensor Layouts E 1 Sensor layouts 179 xvi Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 PREFACE elcome to the Geodesic Photogrammetry System GPS from Electrical Geodesics Inc EGI The GPS consists of a geodesic dome structure Sy containing 11 mounted cameras a motorized steel gantry and the Photogrammetry TEA software feature in Net Station The GPS also comes with a data acquisition computer e E and monitor hae E amp Eike pg Kir iad When used with the Geodesic Sensor Net GSN and Net Station software the GPS PHOTOGRAMMETRY ee enables you to digitize dense sensor array locations conveniently and accurately The GPS file icon Sensor registration is considered essential to projects involving high density electroencephalography EEG such as source localization Typical sensor registration is labor and time intensive requiring a technician to use a stylus or other device to touch each sensor on the subject s head The GPS simplifies this process by dividing it into two image acquis
124. nterruptible power supply or a battery in Uy for 5 sec in Uz for 5 sec Power frequency 3 A m 3 A m Power frequency magnetic fields should 50 60 Hz be at levels characteristic of a typical magnetic field location in a typical commercial or IEC 61000 4 8 hospital environment Note Uz is the a c mains voltage before application of the test level Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 169 C EMC Declarations for GPS Table C 3 lists the EMC immunity guidelines and declarations for non life supporting equipment such as the GPS Table C 3 Electromagnetic immunity for non life supporting equipment GPS The Geodesic Photogrammetry System GPS is intended for use in the electromagnetic environment specitied below The customer or the user of the GPS should ensure that it is used in such an environment IEC 60601 Compliance Immunity test test level level Electromagnetic environment guidance Portable and mobile RF communications equipment should be used no closer to any part of the GPS including cables than the recommended separation distance calculated from the equation applicable to the frequency of the transmitter Recommended separation distance Conducted RF 3 Vrms 3 Vrms d 1 2 VP IEC 61000 4 6 150 kHz to 80 MHz Radiated RF 3 V m 3 V m d 1 2VP 80 MHz to 800 MHz IEC 61000 4 3 80 MHz to 2 5 GHz d 2 3 VP 800 MHz to 2 5 GHz where P i
125. nual S MAN 200 GPSR 001 e November 22 2006 177 D Calibration Target Layouts Figure D 10 Camera view 10 Figure D 11 Camera view 11 178 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 appendix E SENSOR LAYOUTS Table E 1 is a guide to the sensor layouts contained in this appendix Table E 1 Sensor layouts Page number Sensor layout page 180 32 channel HydroCel GSN v1 0 Adult page 181 64 channel GSN 200 v2 0 Adult page 182 64 channel HydroCel GSN v1 0 Adult page 183 128 channel GSN 200 v2 0 Adult page 184 128 channel HydroCel GSN v1 0 Adult page 185 256 channel GSN 200 v1 0 Adult page 186 256 channel HydroCel GSN v 1 0 Adult You may want to photocopy and enlarge the following sensor layouts and have the appropriate sensor layout readily at hand when you begin to mark and edit cardinal and non cardinal points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 179 E Sensor Layouts O Cardinal point Figure E 1 32 channel HydroCel GSN v1 0 Adult 180 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 E Sensor Layouts O Cardinal point Figure E 2 64 channel GSN 200 v2 0 Adult Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 18 E Sensor Layouts O Cardinal point Figure E 3 64
126. ols to help you visualize the sensors and to determine their numbers Which ones you find most useful will depend on personal preference In general however the following have proven popular with users e Onion Skin camera filter e Inverse camera filter e 3D Point Cloud camera overlay e The appropriate sensor layout for the Net used e Sensor Locations window e Mark Solved button in the Sensor Locations window e Change Number dialog Also after editing your User mark in the camera views remember to click the Update Model button or Identify Sensors button if the sensors have not been assigned their sensor numbers to view the effect of your edits 152 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 12 GPS FAQs What is the difference between Update Model and Identity Sensors Update Model is similar to Identify Sensors in that it uses your User marks and a built in EGI Head Model to triangulate positions for the GSN sensors The main difference is that Identify Sensors assigns sensor numbers to your User marks and Update Model does not Your cardinal and your non cardinal points must be identified once each that is at each stage cardinal and non cardinal you must click the Identify Sensors button and the numbers must be assigned Once your set of User marks has been identified and automatically numbered by the Photogrammetry software if you make further edits to the
127. ordinate 24 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 1 System Overview Calibration The GPS process depends on accurate calibration of the camera system so that the lines of sight to each sensor in a GSN can be projected precisely into space and the locations can be triangulated accurately Theory With the GPS a linear camera model is created by defining 11 parameters e camera location 3 parameters e camera orientation 3 e focal length 1 e pixel scale 1 e pixel aspect ratio 1 e image plane center offset 2 These parameters are used to define a projection operator for each camera which maps from a 3D point in space to a 2D location in the acquired image From these physically defined parameters a linear polynomial camera projection operator can be defined as follows ax by czt d ex fyt ezth u L VS aeee x y tkz l ix jy ekg where a k are the camera parameters x y and z are the object model point coordinates and u and v are the image coordinates If a single object with 3 space coordinates x y and z is viewed through two or more cameras then a linear system with distinct camera parameters and image coordinates for each camera can be formed The resulting system has three unknowns and 2 n equations where n is the number of cameras This system is solved using pseudo inverse methods to obtain a least squares estimate of the 3 space coordina
128. p RIER TIRI FFD Se Fe SER EREEE amp k 7 Click on the Number column and on the sort toggle to sort the results by number scroll down to 31 which has been marked in only one camera view camera 2 110 2 Proceed to camera view 2 and mark the visible cardinal points 1 Up 1 3 Up 3 All Images A Model 38M Observations Sensor Locations info Window il Compare Nets 5 To edit the User marks choose View gt Sensor Locations to open the Sensor Locations window 8 In the 3 Up window view sensor 31 using a camera triad that includes camera 2 e g 2 7 11 3 Continue marking the cardinal points in each camera view when done save a copy of the marked up file In the original tile click the Identity Sensors button ELR AMG GATE S984 TII TOL PAM BON 2479 261 IOL 1L749 6489 2 608 2464 D0 PIES 1AE 6 007 Ep 12a PJAN LAG BAT 201 Le 4431 LITR LF Acad 17B et 2 APG Gules 11A S406 LEES ITIL E E E E EE EEE 6 Click on the Solved column and on the sort toggle arrow button to view the solved cardinal points In this example sensor 31 is missing from the list of solved cardinal points for a 256 channel HCGSN 9 Click the pedestal of sensor 31 in either of the other camera views and click the Identify Sensors button the software will automatically number the User mark and the cardinal point solution will be identified Figure 8 3
129. parentheses in the Sensor Locations window Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 115 8 Sensor Modeling 116 Editing Instructions To solve unsolved sensor locations you will need a sensor layout see Appendix E Sensor Layouts You may also need to apply a variety of camera views and overlays see pages 124 and 125 to improve visibility of the sensors and to view their true numeric IDs Following are instructions on how to edit points 1 Choose View gt Sensor Locations and view the unsolved points Figure 8 9 6000 Sensor Locations Number Cameras i Coordinate FA 54 0 000 13 129 2 755 0 044 76 4 5 9 0 0000 14 145 0 910 0 198 75 9 0 000 12 752 3 699 2 806 71l 5 9 10 0 000 13 467 4 621 0 065 65 5 0 000 11 576 7 233 0 127 91 i4 8 9 10 0 000 11 057 5 345 0 152 All unsolved 128 6 10 11 0 000 4 577 9 391 2 781 78 4 0 000 13 215 2 326 5 148 S 101 3 4 3 0 000 6 753 7 823 1 873 Camera lists 90 4 3 0 000 11 436 3 877 2 152 57 amp 10 0 000 7 204 9 931 1 571 70 5 9 10 0 000 12 028 5 771 2 047 8 amp 3 4 9 0 000 12 344 1 798 2 842 7 74 9 0 000 11 645 3 840 5 367 Mark Solved Figure 8 9 Sensor Locations window 2 Foran unsolved sensor double click on its camera list to open a 3 Up window the sensor is circled in the camera view s see Figure 8 2
130. r keyboard or at the back of your computer A light should illuminate within the key 4 Open the Net Station install folder in the Applications folder on your hard drive 5 Double click on the NS Remote HASP Updater icon which will open the Updater dialog 6 Make sure that the Update HASP tab is frontmost in the Updater dialog Net Station Remote HASP Updater Assigned To Ling Chan E f Create Update Fil Locate your Net Station Update file from EGI Drag it into the box at the left 7 Drag the Updated file into the Update box ar Net Station Remote HASP Updater Assigned To Ling Chan Create Update File 8 A dialog will appear with a message indicating a successful update Your HASP has been updated You may now run Net Station 9 Delete the Updated file and any compressed copies from your Desktop Figure B 5 Apply the Updated file from EGI to the corresponding HASP Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 165 B Updating EGI Licenses Questions Contact EGI at support egi com with any questions regarding this document and the issues discussed 166 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 appendix C EMC DECLARATIONS FOR GPS The Geodesic Photogrammetry System GPS needs special precautions regarding electromagnetic compliance EMC and needs
131. ra pop up menu on page 101 6 Camera view Described in 6 Camera view on page 101 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 103 7 Image Acquisition 104 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 chapter 8 SENSOR MODELING S ensor modeling involves using the acquired images to register sensor positions It entails marking sensors in each of the 11 images in Net Station by clicking on them in any order with the mouse initiating Photogrammetry s triangulation calculation and editing the marks on the images to improve the triangulation model This chapter describes modeling principles lists the cardinal points for the GSN 200s and the HCGSNs and provides step by step modeling instructions Detailed descriptions of the Model window and its modeling tools the Observations window and the Sensor Locations window round out the chapter and begin on page 118 Note Because the modeling stage entails careful work by the user this chapter delves into the details of the modeling process If you wish to model sensors immediately go to page 110 where the instructions begin Process Overview The GPS is designed to make the modeling of sensors as convenient as possible Using the Photogrammetry software a click of the mouse or other cursor device marks a sensor in an image Photogrammetry records your clicks onscreen with brightly
132. relative humidity should be at least 30 If an ESD interrupts the GPS camera function image acquisition will need to be repeated Electrical fast 2 kV for power 2 kV for power The GPS does not feature high level EFT transient EFT supply lines 1 kV supply lines 1 kV protection EFTs may interrupt the USB burst for input output lines for input output lines communications between the cameras IEC 61000 4 4 and the computer Mains power quality should be that of a typical commercial or hospital environment If an EFT interrupts the GPS camera computer communications image acquisition will need to be repeated Surge kV differential 1 kV differential Mains power quality should be that of a IEC 61000 4 5 mode 2 kV mode 2 kV typical commercial or hospital common mode common mode environment Voltage dips lt 5 Uz gt 95 dip lt 5 Uz gt 95 dip Mains power quality should be that of a short in U7 for 0 5 cycle in Uz for 0 5 cycle typical commercial or hospital interruptions and 40 Uy 60 dip in 40 Uz 60 dip in environment If the user of the GPS voltage variations U for 5 cycles U for 5 cycles requires continued operation during on power supply 70 Uz 30 dip in 70 Uz 30 dip in power mains interruptions it is input lines Us for 25 cycles Us for 25 cycles recommended that the GPS be powered IEC 61000 4 11 lt 5 Uz gt 95 dip lt 5 Uz gt 95 dip from an uni
133. ry WARNING Follow the assembly instructions carefully and review Chapter 3 gt Safety before operating the Geodesic Photogrammetry System For topics not covered in this manual contact EGI Technical Support Appendix A Figure 2 1 The GPS dome and gantry assembled Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 3 2 Hardware Assembly GPS Environmental Conditions The GPS is designed for use under the environmental conditions listed in Table 2 1 For information about electromagnetic compliance EMC see Appendix C Table 2 1 Overall operating environment Storage temperature 10 to 50 C 14 to 122 F Operating temperature 10 to 35 C 50 to 95 F Relative humidity 5 to 95 noncondensing Maximum altitude 3 000 m 9 842 ft Site Requirements The site requirements fo4r the assembled GPS gantry and dome are listed in Table 2 2 Table 2 2 Site requirements Location In or adjacent to the room containing the EGI data acquisition setup Area 102 x 150 cm or 40 x 59 in w x d Ceiling height 221 cm 87 in Door width 89 cm 35 in if dome is separated from gantry and tilted sideways 6r 102 cm 40 in if GPS is assembled Lighting Even and diffuse no exposed light bulbs May need to open curtains or blinds for additional natural light Subject chair Low backed chair for clear lines of sight from the cameras to
134. s from Figure 7 5 1 Camera view buttons Described in 1 Camera view buttons on page 100 2 Take Pictures button Described in 2 Take Pictures button on page 100 3 Accept Pictures button Described in 3 Accept Pictures button on page 100 4 Camera view Described in 6 Camera view on page 101 5 Camera label Indicates the camera associated with the view 102 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 7 Image Acquisition 1 Up Window The 1 Up window provides the closest view of the sensors It displays an image captured by one camera with a maximum scale of 1 1 Use this window during image acquisition to check the visibility of difficult to see sensors cameras 4 5 and 9 for example Figure 7 6 shows the 1 Up Acquisition window r Cra ry a r ae f j a 7 gt i i j j 7 d Click the 1 Up 3 button leftmost for the closest 4 view 5 6 Verion Lb Figure 7 6 1 Up Acquisition window The following are references for the numbered items from Figure 7 6 1 Camera view buttons Described in 1 Camera view buttons on page 100 2 Take Pictures button Described in 2 Take Pictures button on page 100 3 Accept Pictures button Described in 3 Accept Pictures button on page 100 4 Navigation tool Described in 4 Navigation tool on page 100 5 Camera pop up menu Described in 5 Came
135. s into the power supply cable located on the front of the gantry s main body The cameras are not numbered on the dome For reference Figure 2 9 shows the camera numbering scheme which has clockwise from top to bottom camera 1 pointed up and camera 2 pointed forward Camera 9 faces the gantry Connecting the Dome to the Gantry Assembly requires securing the dome to the dome support on the gantry Three sets of bolts are fastened in their correct positions on the dome support before shipping The locations are in vertical and horizontal positions The bolt sets are listed in Table 2 7 which also shows a photograph of the bolt sets on the vertical and horizontal arms of the dome support Table 2 7 Dome support bolt sets Location Components Photo Vertical pipe clamp 1 4 20 x 2 bolts 3 8 acorn nuts 3 8 flat washers shims aA Vertical Horizontal pipe clamp 1 4 20 x 3 bolts 3 8 acorn nuts Horizontal To secure the dome to the dome support e carefully remove the dome from its crate e remove the protective foam tubing from the dome e remove the acorn nuts and the top halves of the pipe clamps on the gantry s dome support e position the dome so that it fits within the bottom halves of the pipe clamps on the dome support and e reattach the top halves of the pipe clamps and the acorn nuts Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 A3 2
136. s the maximum output power rating of the transmitter in watts W according to the transmitter manufacturer and d is the recommended separation distance in meters m Field strengths from fixed RF transmitters as determined by an electromagnetic site survey should be less than the compliance level in each frequency range Interference may occur in the vicinity of equipment marked with the following symbol Note 1 At 80 MHz and 800 MHz the higher frequency range applies Note 2 These guidelines may not apply in all situations Electromagnetic propagation is affected by absorption and reflection from structures objects and people a Field strengths from fixed transmitters such as base stations for radio cellular cordless telephones and land mobile radios amateur radio AM and FM radio broadcast and TV broadcast cannot be predicted theoretically with accuracy To assess the electromagnetic environment due to fixed RF transmitters an electromagnetic site survey should be considered If the measured field strength in the location in which the GPS is used exceeds the applicable RF compliance level above the GPS should be observed to verify normal operation If abnormal performance is observed additional measures may be necessary such as reorienting or relocating the GPS b Over the frequency range 150 KHz to 80 MHz field strengths should be less than 3 V m 170 Geodesic Photogrammetry System Technical
137. solution Indicates the number of pixels per image It is often represented as N x M where N and M are the number of pixels per column and per row respectively RMS See root mean square root mean square The square root of the average of the squares of a set of numbers Used in statistics S sensor A device that picks up a signal being generated by something in the real world sensor layout Descriptive information for a particular quantity and arrangement of sensors Includes 2D and or 3D coordinates specifying the locations of sensors labels names of sensors and connectivity Such information is stored in a sensor layout file T tessellate To cover a surface with interlocking patterns S MAN 200 GPSR 001 November 22 2006 189 Glossary 3D Point Cloud The 2D User marks projected into 3D space by means of the Photogrammetry algorithm and Calibration values toggle Changing between two states For example each time a button is clicked it changes the state of what it is controlling to one of two possible states and is said to toggle between the states U USB Stands for Universal Serial Bus A plug and play interface between a computer and add on devices Allows devices to be added to a computer without having to add an adapter card or to even turn off the computer V vertex The point on an EEG subject s scalp that is closest to the top of the head located midway between the nasion and inion a
138. successfully These questions have been asked by EGI testers support staff and customers and we hope they prove useful to you If you have a new FAQ to submit please send it to support egi com and we will add it to this chapter A table listing the software error messages and possible user solutions rounds out the chapter Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 147 12 GPS FAQs General Issues How does the GPS compare with a competing sensor registration product The GPS performs comparably with other systems Data from the GPS method were compared with data acquired with a conventional electromagnetic method The accuracy of the GPS method quantified as RMS of the measured positions and the actual known positions was similar mean error 1 27 mm to the electromagnetic method mean error 1 02 mm and both approximated the localization error of the Calibration Object mean error 0 56 mm For a copy of an EGI white paper about this study contact support egi com Why choose the GPS over competing sensor registration products The accuracy of the GPS may be comparable with other systems but its convenience is unmatched Here are just a few highlights e Decreased subject time The subject is needed just long enough to have his or her picture taken within the GPS dome other systems require the subject to sit still for 20 or more minutes e Complete system The GPS is design
139. t for the correct sensors Do need to number the points myself No that s what the Identification function does After you mark the points in any order in the 11 camera views click the Identify Sensors button The software compares your User marks with the built in EGI Head Model of that Net model and assigns the correct sensor ID numbers to the User marks Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 151 12 GPS FAQs However you may need to number individual points manually if e The software has incorrectly numbered them Check the appropriate sensor layout for the numbering scheme manually renumber the points in the camera views and click the Update Model button e A point is marked in only one camera view Because you need at least two points to triangulate a position view the point from another camera view mark and number it appropriately and click the Update Model button Do need to number the calibration targets myself Yes Fortunately there are only 36 calibration targets and in most cases you will need to calibrate the GPS only once Calibration is required after you set up the system If you disassemble and reassemble the system e g to move it to a new building or reinstall the software then you must recalibrate it Modeling the Points What are some helpful tools to use to solve unsolved points The Photogrammetry software offers a variety of to
140. ter 8 Cords Connectors and Cables 54 Disassembly 55 Cleaning 55 Software Installation 57 System Requirements 57 GPS Package Contents 57 Software Installation 58 File Organization 58 Starting Net Station 59 Startup and Menus 61 Starting Photogrammetry 61 Photogrammetry Dialog 62 Photogrammetry Menu Bar 64 Opening a GPS File 73 Camera Calibration 75 Calibration Principles 75 Calibration Overview 76 Image Acquisition 78 Modeling the Targets 82 Error Messages 87 The Calibration Pane 91 The Calibration Files 92 Image Acquisition 95 Acquisition Principles 95 Acquisition Overview 95 Before Image Acquisition 97 Image Acquisition Instructions 97 Acquisition Window 99 Sensor Modeling 105 Process Overview 105 Saving File Copies 109 Cardinal Points 109 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 Contents Cardinal Point Instructions 110 Non Cardinal Point Instructions 117 Model Window 118 Additional Window Tools 124 Other Modeling Tools 131 chapter 9 Data Export 137 Export Principles 137 Export Instructions 139 chapter 10 Compare Nets 141 Compare Nets Principles 141 Net Comparison Window 142 Compare Nets Instructions 144 chapter 11 Printing GPS Images 145 Screen Shots 145 TIFF Images
141. tes Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 25 1 System Overview These coordinates are substituted into the projection operator to obtain new values for the image coordinates u and v the difference norm root mean square or RMS error between the measured and the projected image coordinates is used as a measure of the consistency between the observed image coordinates Practice The GPS Calibration Object is a precisely manufactured sphere with 36 calibration targets marked and labeled on its surface the x y z coordinates of each target are known in the GPS software To calibrate the GPS place the Calibration Object in the geodesic dome acquire an image set and in the acquired images mark and number the calibration targets An optimization procedure is used for the camera parameters so as to place all the calibration targets on a spherical surface of the correct radius while maintaining high convergence between intersecting rays corresponding with each target Once a camera is calibrated a point within an image defines a ray in space which must intersect the position of the point in 3D space The intersection of two such rays from two different cameras uniquely defines that 3D position Calibration instructions are provided in Chapter 6 Modeling With the GPS you create 2D User marks by clicking on visible sensors in each of the 11 acquired images Once the marking is comp
142. that image in the 1 Up mode Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling This window is useful for quickly surveying the acquired images The window contains few buttons and options it is perhaps more useful for acquiring images see Chapter 7 Image Acquisition Figure 8 10 shows the All Up Model window ON Click the All Up button rightmost to view all 11 4 thumbnails 5 6 The camera views are in the same positions as the cameras in the GPS camera structure 7 eee kasaa Liia Figure 8 10 All Up Model window The following are brief descriptions of the numbered items from Figure 8 10 1 Camera view buttons Allow you to view the subject from the viewpoint of one camera three cameras or 11 cameras These buttons are visible in all Model and Acquisition windows 2 Identify Sensors button Signals the software to map the sensors 2D locations and true numeric IDs triangulate locations and mark points as solved or unsolved Click this button after marking points in all 11 images 3 Update Model button Signals the software to triangulate locations and to update the 3D Point Cloud which is a projection of the 2D User marks into 3D space Click this button after making changes to the User marks Observations window or Sensor Locations window of an identified data set Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 00
143. the GPS really important Yes If you have glare from exposed lighting then some of your points may be difficult or impossible to identify correctly The lighting must be even and diffuse Why are some of my camera views tinted red A red camera view indicates insufficient lighting in the room Adjust the lighting and try acquiring images again Insufficient lighting is often the reason for image acquisition failures What can I do if some cameras are out of focus Contact support egi com for instructions You cannot focus the cameras yourself and most likely will need to return the GPS to EGI for servicing by trained personnel What are some common image acquisition issues Marking and editing the points is difficult if the acquired images are of poor quality Before saving your images to disk remember to e Manage the wires of the GSN 200 Clumps of wires from the GSN 200 can obscure sensor pedestals especially when viewed from cameras 4 5 and 9 Make sure that you use some sort of wire management technique e g distribute the wires evenly throughout the web structure so that no one area such as the back of the head is blanketed by a majority of the wires e Center the subject Try to center the subject in each of the 11 camera views Try to ensure that no part of his or her head is cut off and that as many sensors as possible are visible for registration e Upright the sensors Tilted or overturned sensors cannot be
144. the mark is not correctly marked you can edit it by Deleting press the Shift key and move the cursor over the point until you see the delete symbol click to remove the point Moving move the cursor over the point until you see the move symbol drag the mark to the new location e Renumbering double click on the mark to open the Change Number dialog and type in the correct number To undo an edit press Command z 7 Go to the next camera view by e clicking the Navigation forward button e clicking on camera 2 in the dome diagram or e choosing camera 2 from the camera pop up menu Repeat Steps 4 6 and save your work continue to the next camera view until each image has been marked 8 After marking all images save a copy of the file In the original file click the Calibrate button which signals the software to calculate the 3D locations of the targets on the Calibration Object the calibration process can take 10 15 minutes depending on computer capacity If the high error message appears go to RMS Error Is High on page 89 If no message appears the calibration was successtul Go to Chapter 7 Image Acquisition to begin acquiring subject image sets with the calibrated GPS Saving a copy of the marked up file is usetul if you wish to redo the editing but not the marking Figure 6 10 Expanded view of Steps 6b 8 in marking the calibration targets 86 Geodesic Photogramme
145. thing hair and body parts well away from moving parts Use caution when operating to prevent injury 98 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 7 Image Acquisition Acquisition Window The Acquisition window offers three camera view options 3 Up All Up and 1 Up Figure 7 2 Figure 7 2 3 Up All Up and 1 Up Acquisition windows 3 Up Window The 3 Up window displays trios of images called triads from adjacent cameras Images are scaled to fit the window Double click in one of the three camera views to display that image in the 1 Up mode Because the cameras are adjacent the triads represent a set of cameras most likely to be involved in triangulating a point Therefore you can use the 3 Up window to check lines of sight and to increase the chances for a good triangulation The default camera triad is 1 2 3 Click the forward button of the Navigation tool described in 4 Navigation tool on page 100 to Navigation fool make the next triad appear 1 3 4 or click in the triangular space forward button between cameras in the GPS dome diagram Occasionally you may want to select nonadjacent cameras manually because the lines of sight in 3D are better You can select these cameras using the camera pop up menus above the camera views Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 99 7 Image Acquisition Figure 7 3
146. tionable means that the software can only estimate the sensor location and number You will use various modeling tools to confirm or correct these estimates Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling meas OG vle E mt ag 1 Co Solved cardinal AS C NG T E Na point blue Solved non cardinal am D At ol Tee 143 point bright green 15 24 130 0 9 50 ef 99 2 59 142 49 58 129 Questi ble FEN 288 A Coa 7141 HestiOncnle 157 465 66 478 hes point pink Gd 72 77 87 Goa 110 119 2140 ie 127 70 76 36 yg ia 118 y Fr SATA TNO Y 54 el 25 Unsolved An 107 116 cardinal point khaki 95106 124 94 LNS green 1054 f SIERE 122 Figure 8 7 Sensor status by color in the Model window If you have difficulty discerning the different colors you can obtain the same information by choosing View gt Sensor Locations The solved locations are represented by a green dot in the Solved column the unsolved by no green dot in the Solved column and the questionable by parenthesis around the camera list Figure 8 8 Sensor Locations 30 0 000 3 670 6 696 9 086 Solved 31 2 7 0 707 11 009 1 482 3 343 0 0 000 10 648 2 808 4 674 0 000 9 588 4 234 5 813 Unsolved 0 000 8 167 5 470 6 618 0 000 6 710 6 519 7 184 Questionable 36 6 0 000 4 975 7 136 7 810 Clear Solved Figure 8 8 Point status by dot or
147. try System Technical Manual S MAN 200 GPSR 001 e November 22 2006 6 Camera Calibration Note Each time you double click on a calibration target to number it the software defaults to 1 Therefore for camera view 1 it is best to mark target 1 last Error Messages This section describes common calibration related error messages For more information about other Photogrammetry error messages see page 156 Retry Initialization After clicking the Capture Images button the unable to acquire images message may appear Figure 6 11 Unable to acquire images in all cameras Figure 6 11 Unable to acquire images This window can result from various factors such as lighting or USB problems To solve 1 Check that the room lighting is even and diffuse with no lights directly pointed at the cameras Opening the room s curtains or blinds may help Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 87 6 Camera Calibration 2 Click the OK button in the unable to acquire images dialog which opens the retry window In this window click the Retry Initialization button to reattempt to establish connection with the cameras Figure 6 12 atera iz E ri SSS 7 Retry Initialization ee A l ai eT KOy hy ait Comer a Camera 3 H Figure 6 12 Retry window If successful the default Acquisition window appears Figure 6 13 Figure 6 13 The default Acquisitio
148. tton only once no error message will appear even if a large number of sensors are unsolved or questionable Thereafter click the Update Model button after making any edits to the User marks unless you want the software to renumber points or recalculate the solution set In this case click the Identify Sensors button e Because of the many more points to solve compared with the cardinal point mode it can be difficult to determine the correct numbering of the sensors Refer to the sensor layouts Appendix E Sensor Layouts or the EGI Head Model overlay while renumbering unsolved points e If editing proves problematic you can always redo the sensor editing work in the marked up non cardinal file you saved see Saving File Copies on page 109 e To export your data go to Chapter 9 Data Export Model Window Similar to the Acquisition window the Model window offers three camera views All Up 3 Up and 1 Up The Model window provides additional features such as the model view three camera filters Normal Inverse and Onion Skin and three camera overlays EGI Head Model 3D Point Cloud and Numbers These are discussed in Additional Window Tools on page 124 All Up Window The All Up window contains 11 thumbnails representing 11 different perspectives The camera views are arranged in the same pattern as the cameras in the GPS camera structure Double click in any of the camera views to display
149. ttp www store apple com Power cord from dome to gantry Monitor Keyboard Computer USB USB USB Mouse Isolation transformer Power Figure 2 14 GPS connectivities Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 49 2 Hardware Assembly Isolation Transformer Inside the gantry are a power supply isolation transformer and actuator motor for moving the dome vertically Both the power supply and actuator motor plug into the isolation transformer which plugs into mains supply The purpose of the isolation transformer is to provide isolation from ground for all components plugged into it As a result if a person inadvertently comes into contact with these components and an electrical potential the transformer will prevent a current flowing from these components through the person s body to ground The isolation transformer is an international medical hospital grade unit from Toroid Corporation of Maryland The transformer is fused for 3 15 AT 120 V or 1 6 AT 240 V its capacity is 300 VA max For fuse replacement instructions refer to the transformer operating instructions Table 2 9 lists the transformer s specifications Table 2 10 lists the power consumption values for the GPS Table 2 9 Isolation transformer specifications Fuse rating 3 15 AT 120 V or 1 6 AT 240 V Capacity 300 VA max Compliance UL2601 1 CSA C22 2 No 601 1 EN
150. tuberance on the midline of the occipital bone at the base of the skull below which the skull curves inward to the foramen magnum the opening through which the spinal cord enters the brain S MAN 200 GPSR 001 e November 22 2006 Geodesic Photogrammetry System Technical Manual nasion The point where the bridge of the nose meets the skull Net Station EGI s data acquisition and processing software P paradigm An example that serves as a pattern or model parameter A measurable factor such as temperature that helps define a system and its behavior photogrammetry The technique of measuring objects from photograms Its most important feature is that it allows objects to be measured without being touched pixel A single picture element A pixel is a point in 2D with a single color value The number of pixels visible on a monitor is controlled by the monitor s resolution setting polyhedron A solid whose faces are polygons closed plane figures bounded by three or more line segments preauricular point The indentation just in front of the ear flap pinna where the jaw meets the skull Phong shading A model of how light is reflected from surfaces Used extensively in 3D graphics to generate visually realistic images Glossary reference An electrical point that is treated as zero for purposes of amplifying electrical signals The Geodesic Sensor Net has a reference electrode located at the vertex re
151. u Repeat Steps 4 6 and save your work continue to the next camera view until each image has been marked 6 Camera Calibration Numbers button 3 Click the Numbers button which enhances the visibility of the User marks 6a If the mark is precisely positioned and numbered correctly repeat the process for the other targets in the camera view 8 After marking all images save a copy of the file In the original file click the Calibrate button the calibration process can take 10 15 minutes depending on computer capacity If the high error message appears go to RMS Error Is High on page 89 If no message appears the calibration was successful Go to Chapter 7 Image Acquisition to begin acquiring subject image sets with the calibrated GPS Figure 6 7 Marking the calibration targets S MAN 200 GPSR 001 e November 22 2006 83 6 Camera Calibration 8 Photogrammetry ew cose airan Net Size Calibration Object B 1 Click the Open Dataset to open the Model window for the acquired calibration image set or open the file using standard file opening methods see Opening a GPS File on page 74 Name Calibration Object Number of Sensors 36 Pedestal Height 0 00 GPS Number 20020000 Capture Images d Open Dataset Version 1 0a6 ammi AMO wli 2 Inthe Model window click the 1 Up button to view the image from camera 1 Cal irhip Numbers
152. uctions General Safety Warnings os Following are general safety WARNINGs regarding the GPS As stated in the Preface warnings denote important information that if unheeded could result in serious injury or death e Moving parts are a pinch and crush hazard Keep all clothing hair and body parts well away from moving parts Use caution when operating to prevent injury e Keep objects clear of system during adjustment Doing so will prevent damage or system tipping e Do not immerse or splash electrical equipment Damage or injury may result If liquids are spilled on the GPS s electronic components immediately disconnect it from any power source Do not use a GPS that has suffered exposure to liquids until EGI or other qualified personnel certify that the liquid or liquid residue has not affected device operation or subject safety e Do not use in flammable gas environments Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 53 Moving Warnings The Geodesic Photogrammetry System weighs 77 kg 170 Ib Following are WARNINGs regarding moving the GPS e Do not tip the system greater than 10 degrees in any direction Damage or injury may result Use caution when moving Otherwise damage or injury may result Grounding Warnings Following are WARNINGs regarding the GPS s grounding issues e Only authorized personnel may service this equipment Hazardous mains voltage inside
153. ud and the actual 2D marks on the images the User marks The RMS is calculated in 2D space and measured in units of pixels 5 Coordinate column Indicates the XYZ coordinates of the sensor location If the camera list is enclosed in parentheses then these coordinates are based on User marks and one or more EGI Head Model points Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 Sensor Modeling 6 Sorting toggle Allows you to sort the columns in ascending up arrow or descending down arrow order 7 Delete button Allows you to delete a row by selecting the row and clicking this button 8 Clear Mark Solved button Allows you to designate a model point number as solved or unsolved by selecting an item in a row and clicking this button The status of the button depends on the row selected If an unsolved row is selected the Mark Solved button appears If a solved row is selected the Clear Solved button appears If no row is selected neither button is unavailable Selecting Rows If you double click on an item in a row in the Sensor Locations window the 3 Up window appears with the views corresponding to the first three cameras in the list For example if cameras 1 2 3 and 7 are listed then the views for cameras 1 2 and 3 are shown In each view the selected sensor number is circled and in the model view the sensor is colored red see Figure 8 22 Modei Points
154. uld ensure that it is used in such an environment Emissions test Compliance Electromagnetic environment guidance RF emissions Group 1 The GPS uses RF energy only for its internal function CISPR 11 Therefore its RF emissions are very low and are not likely to cause any interference in nearby electronic equipment RF emissions Class A The GPS is suitable for use in all establishments other CISPR 11 than domestic and those directly connected to the E lic low volt i oneen o Class A ia ow yal saad A network that supplies IEC 61000 3 2 uildings used for domestic purposes Voltage fluctuations Complies flicker emissions IEC 61000 3 3 168 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 C EMC Declarations for GPS Table C 2 lists the EMC immunity guidelines and declarations for the GPS Table C 2 Electromagnetic immunity for GPS The Geodesic Photogrammetry System GPS is intended for use in the electromagnetic environment specitied below The customer or the user of the GPS should ensure that it is used in such an environment Immunity test IEC 60601 Electromagnetic environment test level Compliance level guidance Electrostatic 6 kV contact 6 kV contact The GPS camera function is susceptible to discharge ESD 8 kV air 8 kV air ESD Floors should be wood concrete or IEC 61000 4 2 ceramic tile if floors are covered with synthetic material the
155. urn to Square One If you get lost in trying to solve your sensor coordinates sometimes the best thing to do is choose View gt Info Window and click the Revert to Start button or revert to a previous file A blank slate may be what you need Just be patient and try again Why do I have to mark the fiducial points Fiducial points represent common skull landmarks that enable you to align data acquired with different sensor registration systems You must mark the fiducial points before exporting your data With the GPS you need to mark only the left and right preauricular points because the other fiducial points the nasion and the vertex are covered by sensors whose positions will already be included in the exported data set One rare exception is if the head shape is unusual and the nasion and vertex sensors do not quite sit on those skull landmarks even though the Net is properly applied In this case you may want to mark the nasion and vertex in addition to the preauricular points You can mark the preauricular points at any time even before marking the cardinal points To mark the preauricular points select the appropriate fiducial button in the Model window and click on the preauricular point visible in the camera view A label representing that preauricular point i e LPA or RPA will appear on the image Remember to mark the points in at least two camera views Geodesic Photogrammetry System Technical Manual S MAN 20
156. utton 00o Cal S4ship ol ES Camera W Normal Come button left FF y O a aa 8 V aip Eee Normal Os Biri ms Inverse 0 4 ame 8 OQ Onno Skin button i button middle a right Oo l Onion nverse 2 Skin Version 1 Oot Figure 8 14 The three filtered views Normal Inverse and Onion Skin e Normal Provides an unfiltered view The most familiar of the views it is useful for gathering a general impression of the sensor marks and for marking the sensors e Inverse Reverses the color values to provide a negative view With its x ray view this is good for verifying that the User marks are in the center of the tops of the sensor pedestals e Onion Skin Overlays the image with a white translucent skin of 50 opacity By dulling the background image this enhances the readability of the User marks model points and numbers Camera Overlays These tools allow you to lay different 3D models or numbers over the 2D images The 3D models indicate the goodness of fit of your sensor marks i e how close the positions and numeric IDs of your marks are to the models This comparison allows you to correct point numbers and to solve sensor locations Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 125 8 Sensor Modeling The model overlays are EGI Head Model and 3D Point Cloud The Numbers overlay displays the sensor IDs for each model as
157. w the pictures and click the Accept Pictures if satisfied If unsatisfied repeat Steps 6 8 Figure 6 3 Overview of positioning the Calibration Object for image acquisition 78 Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 8 0 Photogrammetry New Jeiose calibration obj __ Net Size Calibration Object Bb Name Calibration Object Number of Sensors 36 Pedestal Height 0 00 GPS Number 20020000 1 li 1 Capture Images Open Dataset Version 1 0a6 New PhotogrammetryRecording Where Sessions sd Cancel b 6 Camera Calibration 1 Position the Calibration Object on its stand within the GPS dome so that each target labeled from 1 to 11 is pointing toward its respective camera in the GPS dome lower the dome 2 Open the Photogrammetry dialog see Starting Photogrammetry on page 61 choose Calibration Object from the Net Size pop up menu in the Photogrammetry dialog and click the New button 3 In the New Photogrammetry Recording dialog that appears specify a name and destination folder and click New Figure 6 4 Expanded view of Steps 1 3 in positioning the Calibration Object for image acquisition Geodesic Photogrammetry System Technical Manual S MAN 200 GPSR 001 e November 22 2006 79 6 Camera Calibration 669 Photogrammetry Net Size Calibration Object B Name Calibration Object 4 Inthe Photogra

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