software user manual
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1. A T L R Shift Right Mouse Rotate view left right Zoom view in out Unselect everything Centre view on selection Show Hide axes Show Hide cameras Show Hide point labels Show Hide camera to pointrays Show Hide camera field of view Decrease Increase coordinate axes Decrease Increase point size Decrease Increase camera size Pans the view Fit to view window A8 Zooming Panning in an Image The four zoom options available in the active image window are e The wheel of the mouse can be used to zoom in and out e The Z or Y key When the pencil cursor is over the point of interest hold down the Z key to generate a zoom window The cursor can then be accurately placed on the feature point of interest The window will remain open as long as the Z or Y key is held down e The ALT zoom Press the ALT key and use the left mouse button to draw a marquee box that will enclose the enlarged portion of the image The image will be zoomed upon release of the mouse button e The keyboard key to enlarge the image and the key to reduce it To pan or roam within an enlarged zoomed in image hold down the wheel of the mouse and move the mouse The slider bars can also be used for this function as can dragging the mouse with left button held down in Navigate mode accessed by holding down the space bar A9 3D View Functions e To zoom in or out within the 3D view make sure2. Photometrix Australia http www photometrix com au P hoto metrix Last updated July 2013 Users Manual for Camera Calibrator V1 5 This manual comprises three main sections along with two appendices PART A Quick Reference A listing and brief description of all Camera Calibrator menus toolbar buttons cursors and hotkey functions PART B Software overview An explanation of how Camera Calibrator performs camera calibration from digital images with details about the various functions and features of the software PART C Recommended operating procedures How to set up the coded targets and capture suitable imagery for camera calibration APPENDIX 1 Camera Calibrator installation note APPENDIX 2 The End User License Agreement PART A Quick Reference Provided here is a quick reference to the Camera Calibrator menus toolbar buttons cursors hotkeys as well as image and 3D view functions A detailed explanation of how to use the software is presented in Part B Al Main screen menus and toolbar Buttons i Camera Calibrator File Process Help 1 s Aj vi R A2 Pull down menus FILE MENU PROCESS MENU HELP MENU i Camera Calibrator i Camera Calibrator i Camera Calibrator New Ctrl Nn Import Images Open Ctrl 0 View Calibration Parameters Save Ctrl 5 9 stort Save As Run Autocal 1 test cal View 3D f Edit Review measurements Exit Create Rep
3. be presented for example if there is no roll angle diversity in the camera station network which means that all images in the network considered were recorded in landscape mode i e normal camera rotation as indicated by the small buttons on the camera icons in the 3D view Self calibration ideally needs at least one rolled image The following dialog below left will be presented where the process is initiated by pressing Begin AutoCal 20 000mm 0 000mm 0 000mm 0 000e 000 0 000e 000 0 000e 000 0 000e 000 0 000e 000 20 000mm 0 000mm 0 000mm 0 000e 000 0 000e 000 0 000e 000 0 000e 000 0 000e 000 18 112mm 0 323mm 0 060mm 3 248e 004 6 612e 007 6 206e 010 0 000e 000 0 000e 000 0 000e 000 0 000e 000 0 000e 000 0 000e 000 0 000e 000 0 000e 000 Results Results Quality of Self Calibration Quality of Self Calibration 1 0 good Estimated internal accuracy of Referencing Estimated internal accuracy of Referencina pixels 0 09 pixels E Accept Cancel After pressing Begin Camera Calibrator will open and scan each image one by one then perform the automatic camera calibration routine and display the results in the same dialog as above right This process may take several minutes to complete after which the calibration is complete Press Accept and then analyse the results BS y Results The outcome of the automatic calibration routine perfo
4. rent lease sell translate adapt vary or modify Camera Calibrator without the express consent of Photometrix except as expressly authorised by this Agreement to supervise and control the use of Camera Calibrator in accordance with the terms of this Agreement and the Licence to ensure its employees sub contractors and other agents who have authorised access to Camera Calibrator are made aware of the terms of this Agreement to not provide or otherwise make available Camera Calibrator in any form to any person other than those referred to in paragraph 00 without the written consent of Photometrix and WARRANTY The Licensee acknowledges that Camera Calibrator cannot be guaranteed error free and further acknowledges that the existence of any such errors shall not constitute a breach of this Agreement or the Licence Photometrix will replace any defective media at no charge subject to notification of the said defect within 90 days of the date of the commencement of this Licence and provided that the Licensee is responsible for all shipping costs associated with the replacement exercise In the event any statute implies terms into this Agreement which cannot be lawfully excluded such terms will apply to this Agreement save that the liability of Photometrix for breach of any such implied term will be limited at the option of Photometrix to any one or more of the following the replacement of goods to which the breac
5. s Image Scan Settings Part two of the five part process to automatic camera calibration in Camera Calibrator involves setting up the appropriate image scan settings so that the software can automatically identify and measure the coded targets in each image Press the i button on the toolbar Alternatively select Process Image Scan Settings from the pull down menu This opens the first image in the project or is bound to the currently open image and initiates the image scan settings dialog as below Fie Process Help al s a v r IDA Image Scan Settings for Camera Calibration Er 2 DSC_0004 JPG Click a coded target in the background image to zoom in Image scan tolerances Optimize Threshold o 10 Overview Min rays 4 Defaults Coded Target Material Colour Silver Retro Red Retro OK 3 DSC_0005 JPG 4 DSC_0006 JPG v a At this stage Camera Calibrator has an option to automatically detect the type of coded targets used and to adjust the scan settings accordingly Simply press the Optimize button and wait a few moments while the software processes the image then a message will appear for example CameraCalibrator If these settings are appropriate press OK and go on to B4 If not the settings can be adjusted manually by choosing a pixel brightness threshold typically about 10 is a good value to separate the target dot from the background minimum numb
6. International Journal of Photogrammetry and Remote Sensing Vol 52 pp 149 159 This paper is online http www photometrix com au Digital_Camera_Self_Calibration pdf A brief description of each of the 10 parameters of camera calibration is now given Focal Length c and Principal Point xp amp yp This focal length and the principal point offsets indicate how far the optical axis of the lens is displaced from the centre of the image formal The focal length actually refers to the Principal Distance which changes with focusing The nominal lens focal length usually relates to infinity focus Also with zoom cameras this focal length value can vary dramatically but Camera Calibrator seeks one value for the camera used in the survey This is why it is important not to change zoom or focus during the photographic session Generally x amp yp are close to zero e g 0 5mm or less Radial Distortion K Ko amp K3 The three parameters Ki K amp K3 describe the radial lens distortion of the camera lens Radial distortion can reach significant levels in digital camera lenses and it needs to be corrected when computing 3D feature point position to even modest accuracy levels Radial distortion also varies with focusing which is a further reason not to alter focus or zoom within a measurement network Decentering Distortion P amp P2 The parameters P amp P2 express the effect of the decentering of optical elements with
7. PORT WS BAD GES STH SRE STH FSS AL R i PART C Recommended operating procedures C1 Basic Photography Rules There are four basic rules which apply to recording images for photogrammetric camera calibration with Camera Calibrator e The camera lens should not be refocused during the photography session e The lens zoom should not be adjusted during the photography session e Ifthe camera has an auto rotate function which digitally rotates the recorded image the function must be turned OFF e The imagery should be captured on the highest possible resolution i e image size and highest quality For example a 10 megapixel camera should record 10 megapixel images at the highest quality JPEG setting If retro reflective targets are to be used the camera will obviously require a flash If the flash is too bright amp its intensity cannot be controlled sometimes taping a small piece of paper over the flash will have the desired effect or double thickness paper etc C2 Camera Setup and Target Layout for Automatic Camera Calibration The fully automatic camera calibration procedure using Camera Calibrator employs coded targets and self calibration A set of coded targets is provided with the software license In order to carry out the automatic camera calibration via Camera Calibrator the user requires only e A set of at least 12 different coded targets also called codes e A space of about 3 x 3m on whic
8. ameras used in the project If the image files do not contain information which identifies the camera s a warning message is displayed as indicated below This means that before the importing of images into the project camera data must be entered either manually A valid non zero entry must be made for the focal length but it need only be a rough estimate of the true value The image pixel size mm is the only critical value that must be entered Entering the wrong pixel size introduces a scaling effect which is compensated by the computed focal length Unknown image pixel sizes can be calculated as a function of the physical CCD dimension and image resolution See http www photometrix com au images CCD_sensor_sizes gif The default pixel size is set to 0 005mm A typical range for consumer digital cameras is 0 002mm to 0 009mm and it is desirable though not mandatory to enter the correct value here if it is known Adoption of the default pixel size will lead to satisfactory camera calibration results Once the required entries are made click OK to save the camera data This camera will then be added to the camera database so it 1s available next time Camera parameters Image dimensions are 632 pixels wide amp 333 pixels high The following three fields must have valid entry data Enter camera make and model unknown Camera name for Camera default Enter focal length in mm 0 000 Enter the following data if known other
9. bration can be performed with slightly defocused images which might arise from the camera being set to infinity focus but then being used over a distance of only 3m or so Both target array stability and fixed focus are very important The targets are not allowed to move at all If the camera has a manual focus or focus lock it is very useful to set this and then leave it set for the subsequent 3D measurement projects Also attention needs to be given to lighting with well exposed images displaying optimal colour saturation or underexposure being required depending on the coded target material being used An ideal image network geometry for camera calibration is shown below The convergence angle horizontal between the outer two rays should be 70 to 100 it is also very desirable to have such convergence in both directions Note the use of orthogonal roll angles for the camera three images are in landscape orientation and three in portrait It 1s absolutely critical that this 90 variation of roll angle is present It is not important which images are rolled 90 but several should be 14 TT E Eug 1 C3 Other recommendations Camera calibration should be performed periodically using Camera Calibrator say every few months for normal digital cameras or more often if the camera is accidentally dropped or it is used in a relatively rough environment 15 Appendix 1 Camera Calibrator Installation Note T
10. er of rays for each point to be deemed value typically 4 is a good value and the type of coded target material used By left clicking on a coded target in the image the current settings will be applied to the image chip in the dialog giving an indication as to whether they would be acceptable for the overall process Click Overview to zoom the image chip out and operate on a large portion of the image Once the scan settings have been selected press OK B4 Al Automatic Camera Calibration Autocal Once the image scan settings have been selected Camera Calibrator has enough information to perform the calibration A list of the initial camera parameters can be generated in the main window by double clicking on the camera icon see below Caution must be exercised in altering camera calibration values If nothing is known of these other than the approximate focal length value which must always be entered the lens distortion parameters Ki K2 K3 P P2 B amp Bz should be left at either their previously calibrated values or at zero The latter four values will rarely be other than zero and fixed for all practical purposes as indicated below Camera Parameters Information Model NIKON CORPORATION NIKON D200 Calibration date never Unique identifier default Sensor specifics Wide High Resolution pixels 3872 2592 Pixel size mm 0 0061 0 0061 Focal length and principal point c mm 20 0000 Fi
11. ge Measurement 30 View General View keys ALT mouse CTRL mouse SHIFT F F SHIFT T SPACE hold down keys Arrow keys up down DEL Zoom image in out Drag for zoom to selection Drag for point line and polyline selection Fit all images to view windows Fit image to view window Tile all images Image navigation mode Show Hide axes Show Hide point labels Show Hide residual vectors Show Hide reference guiding line Blue predicted points on off Blue predicted polylines on off Referencing mode on off Decrease Increase coordinate axes Increase Decrease image brightness Delete selected points A6 Hotkeys for Image Measurement select via Help menu Camera Calibrator Hotkeys Image General Image Measurement 3D View General r Measurement Arrow keys left right Arrow keys left right 1 2 keys C hold down X hold down zit hold down Move to next previous point in edit review mode Move to next previous point in guided referencing mode Move to next previous point in guided referencing mode Brings up the zoom window for dark color target centroiding Brings up the zoom window for light color target centroiding Brings up the zoom window for referencing marking Camera Calibrator Hotkeys Image General Image Measurement 3D View General 3D graphics view hotkey list Arrow keys left right Arrow keys up down ESCAPE SPACE
12. h relates or the supply of equivalent goods or the payment of the cost of replacing the goods or of acquiring equivalent goods 17 Photometrix will not be liable for any indirect or consequential damages arising out of a breach of this Agreement or the Licence or arising out of the supply of defective Photometrix Products The Licensee acknowledges that it has exercised its independent judgment in acquiring Camera Calibrator and has not relied on any representation made by Photometrix which has not been stated expressly in this Agreement or upon any descriptions or illustrations or specifications contained in any document including catalogues or publicity material produced by Photometrix or a licensed reseller of Photometrix COPYRIGHT The Licensee acknowledges that Camera Calibrator and any associated documentation are the subject of copyright The Licensee shall not during or any time after the expiry or termination of this Agreement permit any act which infringes that copyright and without limiting the generality of the foregoing the Licensee specifically acknowledges that it may not copy the Photometrix Products except as otherwise expressly authorised by this Agreement The documentation may not be copied unless written consent has first been obtained form Photometrix Additional copies of the associated documentation may be acquired from Photometrix The Licensee shall indemnify Photometrix fully against all
13. h to position the codes This will form the target range which will be photographed from a camera to object distance of from say 3 6m depending on the lens focal length and field of view It is desirable to incorporate some 13 3D distribution within the target point array so all points do not lie in a perfect plane Two examples are shown below one using the wall and one using the floor In setting up the target field keep in mind the following Shape of the target array It is preferable for the target field to have depth for example one or more of the 12 coded targets being out of the plane by 10 20 cm or more A target array with some 3D distribution is better than a planar array The camera to object distance The size of the target field will depend upon the distance from which images are to be taken To determine this first set the camera at the focus and zoom setting that you intend to use for subsequent photogrammetric measurement as it 1s critical to calibrate the camera at the same zoom focus that will be normally be employed Typically the focus will be set to infinity and the zoom at one of its hard stops usually zoomed fully out widest field of view Once these settings are made the operator can balance the requirements of imaging distance versus target field dimensions Note that in determining the distance the sharpness of focus in the images is not of great importance An accurate cali
14. he default installation of the Camera Calibrator executable camera database files and documentation will be to the folder C Program Files CameraCalibrator In C Program Files x86 CameraCalibrator there will be two folders as shown dl di CameratCalibrator di cameras di docs Cameras This holds the camera information and associated image chips of cameras within the database You will not need to access this folder unless updating the globalcameras dat Docs This holds the Users Manual 16 Appendix 2 CAMERA CALIBRATOR END USER LICENCE AGREEMENT Warning Permission to use the software Camera Calibrator including any associated media printed materials and online or electronic documentation collectively Photometrix Products is conditional upon you the customer either an individual or a single entity Licensee agreeing to the terms set out below By installing copying or otherwise using the Photometrix Product Camera Calibrator you agree to be bound by the terms of this Agreement If you do not agree to the terms of this Agreement do not install or use Camera Calibrator you may however return Camera Calibrator to your supplier for a refund This document is a legal agreement Agreement between you and Photometrix Pty Ltd ACN 105 272 562 Photometrix Acceptance shall bind you and all of your employees sub contractors and other agents to the terms of this Agreement and of the Licence desc
15. ighlighting thumbnails DSc _0004 JPG GSI PMX red code test 1 DSC_0005 JPG GQ GSI vs PMX red code test DSC_0006 3PG urvey re codes stairs iWitness s gt japanese tracker mappi iNgToolkit_images 5 Updated w leb Site March 07 gt walis gt XYZen s Figure B3 e A single image at a time can be selected or multiple images can be highlighted by using the mouse and dragging Holding down the SHIFT key means all images between two selected images will be highlighted and the gt button can then be used e Press OK when all the appropriate images have been selected for importing into the project 1 e they appear in the right hand side list An up to date list of most digital cameras and their key metric design characteristics 1s provided with the Camera Calibrator software From time to time an updated version of this database is made available for download from http www photometrix com au downloads globalcameras dat Simply download amp save this file then replace the globalcameras dat for the Camera Calibrator in the cameras subdirectory underneath where the CameraCalibrator exe file is installed Camera Calibrator supports JPEG jpg images which are suitable for calibration When JPEG images are imported into the project the program automatically reads the camera type from the exif file header Thus the operator does not have to identify the camera or c
16. in the lens assembly This error source is generally quite small and can typically be ignored in all but very high accuracy applications Linear Distortion B amp B2 These parameters B amp Bo effectively model any relative error in the specified pixel size Thus they can usually be set fixed to zero and ignored After capturing imagery for calibration discussed in Part C there are five main steps to operating the Camera Calibrator software Each step has one tool bar button and each should be completed in order Ss A v R l B2 Importing Project Images amp Associated Camera options When commencing a new Camera Calibrator project press the L button on the toolbar Alternatively select Process Import Images from the pull down menu This initiates a dialog for the importing of images into the project This procedure should be followed e The Image Browser dialog for importing images will appear see below Select the folder that contains the images An image in the Select Image s list is transferred into the project by first highlighting the image or images and then selecting the gt button The gt gt button moves all images into the project Similarly the lt button moves highlighted images out of the project list and lt lt removes all images Image Browser Select Image Directory Select Image s Project Image s aviatrix test data ENCE Images are selected by h
17. liabilities costs and expenses which Photometrix may incur to a third party as a result of the Licensee s breach of the copyright provisions of this Agreement TERM OF LICENCE The Licence commences upon payment of the licence fee and is granted in perpetuity but may be terminated in the following circumstances if the Licensee is in breach of any term of this Agreement if the Licensee being a corporation is wound up has a receiver or receiver and manager appointed to any of its property has a voluntary administrator or provisional liquidator appointed to it or enters into a deed of company arrangement if the Licensee being a firm or partnership is dissolved or if the Licensee destroys the Photometrix Products and documentation for any reason Upon termination the Licensee or its representatives shall destroy any remaining copies of Camera Calibrator and documentation or otherwise return or dispose of such material in the manner directed by Photometrix Termination pursuant to this clause shall not affect any rights or remedies which Photometrix may have otherwise under this Agreement or at law ASSIGNMENT The benefit of this Agreement shall not be dealt with in any way by the Licensee whether by assignment sub licensing or otherwise without Photometrix s written consent WAIVER Failure or neglect by either party to enforce at any time any of the provisions of this Agreement shall not be c
18. onstrued or deemed to be a waiver of that party s rights under the Licence and this Agreement GOVERNING LAW This Agreement takes effect is governed by and shall be construed in accordance with the laws of the state of Victoria Australia and each party hereby unconditionally submits to the jurisdiction of the courts of Victoria and of any court competent to hear appeals therefrom SUPPORT SERVICES Photometrix may provide the Licensee with technical support services related to Camera Calibrator Support Services Use of Support Services is governed by the Photometrix policies and programs described in the documentation accompanying Camera Calibrator and or in other Photometrix provided materials Any supplemental software code provided to the Licensee as part of the Support Services shall be considered part of the Photometrix Products and subject to the terms and conditions of this Agreement With respect to technical information you provide to Photometrix as part of the Support Services Photometrix may use such information for its business purposes including for product support and development Photometrix will not utilise such technical information in a form that personally identifies you 18
19. ort CORPORATION NIKON D2 New project Import images for List of hotkeys Open project calibration About Close project View camera calibration Save project parameters Save project under Access image scan another name settings for automatic Most recent Camera calibration Calibrator projects Run the automatic Exit program camera calibration View the results in 3D Edit Review image measurements Create a PDF report These options are available after camera calibration has been performed A3 Toolbar buttons i s Aj v R Import images for camera calibration S Access image scan settings for open image or first image A Perform automatic camera calibration v View results in 3D RI View summary of results and create PDF report A4 Cursors K Select Cursor used for select functions such as highlighting marquee dragging etc Default cursor or invoked via the Ctrl key Navigate Cursor used for zooming in out or panning within an image left Chee click amp drag invoked via the keyboard Space Bar Cursor for point marking positional adjustment in Edit Review Mode Tip of blue pencil is used to mark or move feature point in an image Not required for fully automatic measurement targets are centroided and should not be moved A5 Hotkeys for Image Handling select via Help menu Camera Calibrator Hotkeys Image General Ima
20. pen the 3D view Controls for the 3D view are explained in Part A B6 Ri Summary of Results and PDF Report Creation Another handy tool to verify the success of the calibration is to view a summary of results Select the R fouton on the toolbar Alternatively select Process Create Report from the pull down menu The following dialog will appear Calibration Results Camera Name NIKON CORPORATION NIKON D200 unique ID default Measurement Network Number of images an Number of referenced points 397 Number of cameras E Quality of geometry 1 0 Minimum number of points on an image 327 on image DSC_0014 PG Minimum point intersection angle 0 degs for point c1265_2 B1 Number of points referenced on 2 images only 3 or more images 4 or more images 6 or more images Measurement Accuracy Summary Estimated accuracy of 3D point coordinates RMS 1 sigma level x 0 0059 units or 1 97700 y 0 0102 units or 1 5700 z 0 0066 units or 1 87500 Overall 0 0076 units or 1 76500 Estimated image measurement accuracy 0 07 pixels RMS 1 sigma level Quality of self calibration if applied 1 0 Create Report Save Print The information presented in this dialog is self explanatory or already explained Press Create Report to export the results in structured 3 page PDF format ready for distribution or filing 12 CAMERA CAUBRATION REPORT 13 CAMERA CALIBRATION REPORT 25 CAMERA CAUBRATION RE
21. ribed below PHOTOMETRIX PRODUCTS LICENCE The Photometrix Product Camera Calibrator is protected by copyright laws and international copyright treaties in addition to other intellectual property laws and treaties The Photometrix Product Camera Calibrator is licensed not sold Pursuant to this Agreement the Licensee acquires a non exclusive right to the Licence at any one time use one copy of Camera Calibrator on a single computer make one copy for backup purposes only and use Camera Calibrator strictly in accordance with the provisions of this Agreement If the Licensee wishes to use Camera Calibrator on more than one computer at the same time it may purchase an additional dongle key from Photometrix or its licensed distributor and such use will be subject to and governed by the terms of this Agreement LICENCE FEE The Licensee is not entitled to use Camera Calibrator until the agreed licence fee has been paid In the case of payment by cheque payment will not be deemed received until the cheque has been cleared A separate licence fee is payable in the circumstances described in clause 0 DOCUMENTATION This Licence extends to any enclosed or related documentation The documentation may not be copied modified or used in any way not contemplated or expressly authorised by this Agreement LICENSEE S OBLIGATIONS The Licensee hereby undertakes the following obligations to not copy reproduce lend
22. rmed by Camera Calibrator is the generation of new camera parameters as shown in above right where the new calibration data is listed alongside the old Measures of a successful camera self calibration can be seen in the Quality of Self Calibration field where an accuracy value along with an indicator of the calibration quality good average or poor is shown The Estimated accuracy of referencing value should always be 0 5 pixels or smaller with a commonly encountered value being around 0 1 0 25 for off the shelf consumer digital cameras Radial and decentering distortion curves and grids can be plotted by choosing Distortion Curves Distortion Grids in the camera parameters dialog Example results are shown below 11 W Radial and Decentering Distortions Decentering Distortion Profile NIKON CORPORATION HIKON D100 Information Grid Vectors Radial Model NIKON CORPORATION NIKON D200 Save Result Radial Calibration date 08 05 2008 13 25pm TER Tee Tee Unique identifier default Both Radial Distortion Profile HIKON CORPORATION NIKOH D100 By far the easiest way to verify the results of a calibration is to view the resulting photogrammetric network in 3D Any mistakes will be obvious for example 1f the points in the network do not logically represent the calibration measurement scene Select the haton on the toolbar Alternatively select Process View 3D from the pull down menu This will o
23. the cursor is over the window the wheel of the mouse can be used e To rotate the 3D View about the axis coming out of the screen hold down the CTRL key and the right mouse button and move the mouse e To pan in the 3D View hold the SHIFT key and the right mouse button and move the mouse e To bring a point to the centre of the 3D View display window first highlight the point left mouse button and drag and then hit the space bar e Moving the mouse with the right button pressed and the point mentioned in the previous dot point still highlighted rotates the display about the highlighted point Also the rotations described in the second dot point will be about the highlighted point e To centre the network in the 3D View use the F key e An Image can be opened from the 3D View by double clicking the corresponding camera A10 Tool tip Display for Image Thumbnails By hovering the mouse cursor over image thumbnails an enlarged version of the image is shown i Camera Calibrator File Process Help CORPORATION N Station is oriented Image contains 379 measurements PARTB Software Overview B1 Introduction to Camera Calibration Photogrammetric measurement is both accurate and reliable but in order to realize maximum accuracy the camera or cameras employed must be calibrated A full explanation of the motive behind camera calibration is given in Fraser C S 1997 Digital Camera Self Calibration ISPRS
24. wise leave as itis Size of image pixel mm 0 005 Camera Image Size of imaging sensor mmm width ag height 1670 Principal point coordinates mm xp a bo YP 0 0 iwitness O x Radial lens distortion coefficients K1 0 0 KZ 0 0 K3 0 0 No camera Found in EXIF header for image s he 8 oe Camera must be selected manually Decentring distortion coefficients P1 0 000e 000 P2 0 000e 000 The camera calibration parameters of focal length principal point offset and lens distortion vary with focus and zoom settings for a lens The possibility arises that multiple sets of calibration data might be needed if the camera is employed either at different lens focus or with different lenses or zoom settings or if different examples of the same camera model are to be calibrated This can create difficulties because the same camera name etc will be read from the EXIF header in the images but the essential calibration data which may or may not be known for the particular lens and focus will be different to that stored for that camera in the database Camera Calibrator overcomes this problem by assigning unique identifiers Unique IDs to given camera lens focus combinations The procedure for assigning a Unique ID which 1s essentially a new entry for an existing camera in the database is simply to type the Unique ID in to the Camera Parameters dialog which is opened by double clicking on the Project Camera icon then press OK B3
25. x xp mm 0 0000 Fix Zero all not c yp mm 0 0000 Fix Radial distortion Distortion Curves Ki 0 0000e 000 Fix K2 0 0000e 000 ee Distortion Grids KF 0 0000e 000 Fix Decentering distortion Run Self Calibration 0 0000e 000 W Fix J 0 0000e 000 W Fix Create Report Linear distortion ___ Create Report 0 0000 W Fix By default in Camera Calibrator the settings B B2 P amp P2 are zero and fixed which locks the value to zero in any calibration Except in the cases of either prior comprehensive calibration or in extremely strong network geometries designed for high accuracy measurement these parameters can generally be left at zero and fixed or at their calibrated values from the comprehensive camera calibration process In cases where the highest possible accuracy is sought for both the calibration and subsequent 3D measurements un tick the boxes for P amp P2 before running a calibration This action however will rarely lead to significant accuracy improvements Also B amp Bz can be un ticked but this should only be contemplated in the very rare cases where it is known that the digital camera has rectangular pixels Click OK 10 The automatic calibration procedure can now be run Select the Al button on the toolbar Alternatively select Process Run Autocal from the pull down menu If the images have already been scanned click Run Self Calibration A warning message may
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