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Agisoft PhotoScan User Manual - Standard Edition, Version 1.1

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1. 4 The data will be loaded into the software Camera calibration data can be inspected in the Camera Calibration dialog Adjusted tab available from Tools menu Camera data can be loaded in one of the following formats PhotoScan xml BINGO dat Bundler out VisionMap Detailed Report txt Once the data is loaded PhotoScan will offer to build point cloud This step involves feature points detection and matching procedures As a result a sparse point cloud 3D representation of the tie points data will be generated Build Point Cloud command is available from Tools Tie Points menu Parameters controlling Build Point Cloud procedure are the same as the ones used at Align Photos step see above Building dense point cloud PhotoScan allows to generate and visualize a dense point cloud model Based on the estimated camera positions the program calculates depth information for each camera to be combined into a single dense point cloud PhotoScan tends to produce extra dense point clouds which are of almost the same density if not denser as LIDAR point clouds A dense point cloud can be edited within PhotoScan environment or exported to an external tool for further analysis To build a dense point cloud le Check the reconstruction volume bounding box To adjust the bounding box use the Resize Region and o Rotate Region toolbar buttons Rotate the bounding box and then drag corners of the box to the desired positions 2 Sel
2. Fe Workspace 1 chunks 32 c Chunk 1 32 cameras gt EM Cameras 22 32 alig se Tie Points 115 964 p Depth Maps 32 Mg Sess Dense Cloud 1 328 4 3D Model 499 999 IMG_3023JPG IMG 3024JPG IMG 3025JPG IMG 3076JPG IMG_3027 JPG io a mila roll General view of application window Model view Model view tab is used for displaying 3D data as well as for mesh and point cloud editing The view of the model depends on the current processing stage and 1s also controlled by mode selection buttons on the PhotoScan toolbar Model can be shown as a dense cloud or as a mesh in shaded solid wireframe or textured mode Along with the model the results of photo alignment can be displayed These include sparse point cloud and camera positions visualised data 38 Graphical user interface PhotoScan supports the following tools for navigation in the 3D view Tool Keyboard modifier Rotation Tool Default Pan Tool Ctrl key pressed Zooming Tool Shift key pressed All navigation tools are accessible in the navigation mode only To enter the navigation mode click the s Navigation toolbar button i Note e Zooming into the model can be also controlled by the mouse wheel Photo view Photo view tab 1s used for displaying individual photos as well as masks on them Photo view is visible only if any photo is opened To open a photo double click on its name on the Workspace or Photos pane Workspace pane On the
3. e Manual polygon removal e Fixing mesh topology More complex editing can be done in the external 3D editing tools PhotoScan allows to export mesh and then import it back for this purpose i Note e For polygon removal operations such as manual removal and connected component filtering it is possible to undo the last mesh editing operation There are Undo Redo commands in the Edit menu Please note that undo redo commands are not supported for mesh decimation and this operation cannot be undone Decimation tool Decimation is a tool used to decrease the geometric resolution of the model by replacing high resolution mesh with a lower resolution one which is still capable of representing the object geometry with high accuracy PhotoScan tends to produce 3D models with excessive geometry resolution so mesh decimation is usually a desirable step after geometry computation Highly detailed models may contain hundreds of thousands polygons While it is acceptable to work with such a complex models in 3D editor tools in most conventional tools like Adobe Reader or Google Earth high complexity of 3D models may noticeably decrease application performance High complexity also results in longer time required to build texture and to export model in pdf file format In some cases it is desirable to keep as much geometry details as possible like it is needed for scientific and archive purposes However if there are no special requirements it is
4. e exporting reconstruction results you can only view a 3D model on the screen To use PhotoScan in the full function mode you have to purchase it On purchasing you will get the serial number to enter into the registration box on starting PhotoScan Once the serial number is entered the registration box will not appear again and you will get full access to all functions of the program Chapter 2 Capturing photos Before loading your photographs into PhotoScan you need to take them and select those suitable for 3D model reconstruction Photographs can be taken by any digital camera both metric and non metric as long as you follow some specific capturing guidelines This section explains general principles of taking and selecting pictures that provide the most appropriate data for 3D model generation IMPORTANT Make sure you have studied the following rules and read the list of restrictions before you get out for shooting photographs Equipment Use a digital camera with reasonably high resolution 5 MPix or more Avoid ultra wide angle and fish eye lenses The best choice is 50 mm focal length 35 mm film equivalent lenses It is recommended to use focal length from 20 to 80 mm interval in 35mm equivalent Fixed lenses are preferred If zoom lenses are used focal length should be set either to maximal or to minimal value during the entire shooting session for more stable results Camera settings Using RAW data losslessly conv
5. Closes holes on the model surface Collects and displays mesh statistics Displays mesh UV mapping Selects masked dense cloud points Builds sparse point cloud based on the estimated camera parameters available Thin point cloud by reducing the number of projections on the individual photos to the given limit Imports edited mesh from the external program Imports edited texture from the external program Imports camera positions and orientation data Imports masks or creates mask from model or background Graphical user interface Tools Menu Export Texture Export Cameras Export Matches Export Masks Export Panorama Undistort Photos Camera Calibration P Optimize Cameras Reset Region Preferences Photo Menu Open Next Photo Open Previous Photo Navigation r 3 L 4 Rectangle Selection 7 Intelligent Scissors A Intelligent Paint A Magic Wand gm Add Selection Subtract Selection 7 F nl Invert Selection Invert Mask a Reset Mask 9 Turn Shading On Off od oo View Points Help Menu Contents 43 Exports model texture Exports camera positions and orientation data Exports tie point measurements Exports masks Exports spherical panorama for camera stations Removes nonlinear distortions by warping source photos Shows camera calibration dialog box Shows camera alignment optimization dialog box Resets reconstruction volum
6. In some cases 1t may be reasonable to edit point cloud before exporting 1t To read about point cloud editing refer to the Editing point cloud section of the manual PhotoScan supports point cloud export in the following formats Wavefront OBJ Stanford PLY XYZ text file format ASPRS LAS ASTM E57 U3D potree PhotoScan OC3 PDF Note e Saving color information of the point cloud is supported by the PLY E57 LAS and TXT file formats e Saving point normals information is supported by the OBJ PLY and TXT file formats Tie points data export To export matching points l 2 Select Export Matches command from the Tools menu Browse the destination folder choose the file type and print in the file name Click Save button In the Export Matches dialog box set export parameters Precision value sets the limit to the number of decimal digits in the tie points coordinates to be saved Click OK button to start export The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button 17 General workflow PhotoScan supports matching points data export in the following formats e BINGO dat saves original intrinsic and extrinsic camera data along with matching points coordinates ORIMA txt PATB ptb Matching points exported from PhotoScan can be used as a basis for AT procedure to be performed in some external software Later on estimate
7. Mild depth filtering mode for important features not to be sorted out If the area to be reconstructed does not contain meaningful small details then it is reasonable to chose Aggressive depth filtering mode to sort out most of the outliers Moderate depth filtering mode brings results that are in between the Mild and Aggressive approaches You can experiment with the setting in case you have doubts which mode to choose Additionally depth filtering can be Disabled But this option is not recommended as the resulting dense cloud could be extremely noisy Building mesh To build a mesh 1 Check the reconstruction volume bounding box To adjust the bounding box use the Resize Region and Rotate Region toolbar buttons Rotate the bounding box and then drag corners of the box to the desired positions If the Height field reconstruction method is to be applied it is important to control the position of the red side of the bounding box it defines reconstruction plane In this case make sure that the bounding box is correctly oriented Select the Build Mesh command from the Workflow menu In the Build Mesh dialog box select the desired reconstruction parameters Click OK button when done The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button Reconstruction parameters PhotoScan supports several reconstruction methods and settings which help to produce optimal
8. based on the sharpness level of the most focused part of the picture To estimate image quality k Switch to the detailed view in the Photos pane using Details command from the Change menu on the Photos pane toolbar 2 Select all photos to be analyzed on the Photos pane 3 Right button click on the selected photo s and choose Estimate Image Quality command from the context menu 4 Once the analysis procedure is over a figure indicating estimated image quality value will be displayed in the Quality column on the Photos pane Saving intermediate results Certain stages of 3D model reconstruction can take a long time The full chain of operations could easily last for 4 6 hours when building a model from hundreds of photos It is not always possible to finish all the operations in one run PhotoScan allows to save intermediate results in a project file PhotoScan project files may contain the following information e List of loaded photographs with reference paths to the image files 15 General workflow e Photo alignment data such as information on camera positions sparse point cloud model and set of refined camera calibration parameters for each calibration group e Masks applied to the photos in project e Depth maps for cameras e Dense point cloud model e Reconstructed 3D polygonal model with any changes made by user This includes mesh and texture if it was built e Structure of the project 1 e number
9. from Full Screen mode Shows or hides camera positions estimated during image alignment Shows or hides region selector Shows or hides the trackball Shows or hides the mesh information on screen display Switches viewport to one of the predefined views Switches visualisation view between Perspective and Orthographic Enable disable stereo view mode accoridng to the parameters specified in Preferences dialog Graphical user interface View Menu cs Workspace Photos Console Toolbar Workflow Menu fre Add Photos ES Add Folder Align Photos Build Dense Cloud Build Mesh Build Texture Align Chunks Merge Chunks Batch Process Tools Menu Decimate Mesh Close Holes View Mesh Statistics View Mesh UVs Select Masked Points Build Point Cloud Thin Point Cloud Import Mesh Import Texture Import Cameras Import Masks 42 Shows or hides Workspace pane Shows or hides Photos pane Shows or hides Console pane Shows or hides Toolbar Loads additional photos to be processed by PhotoScan Loads additional photos from folders to be processed by PhotoScan Generates camera positions and sparse point cloud Generates dense point cloud Generates polygonal model Generates 3D model texture Aligns multiple chunks Merges multiple chunks into the single chunk Opens Batch Process dialog box Decimates mesh to the target face count
10. is completed the point cloud and estimated camera positions can be exported for processing with another software if needed Image quality Poor input e g vague photos can influence alignment results badly To help you to exclude poorly focused images from processing PhotoScan suggests automatic image quality estimation feature Images with quality value of less than 0 5 units are recommended to be disabled and thus excluded from photogrammetric processing providing that the rest of the photos cover the whole scene to be reconstructed To disable a photo use Disable button from the Photos pane toolbar PhotoScan estimates image quality for each input image The value of the parameter is calculated based on the sharpness level of the most focused part of the picture General workflow To estimate image quality l Switch to the detailed view in the Photos pane using Details command from the Change menu on the Photos pane toolbar 2 Select all photos to be analyzed on the Photos pane 3 Right button click on the selected photo s and choose Estimate Image Quality command from the context menu 4 Once the analysis procedure is over a figure indicating estimated image quality value will be displayed in the Quality column on the Photos pane Alignment parameters The following parameters control the photo alignment procedure and can be modified in the Align Photos dialog box Accuracy Higher accuracy setting helps to
11. is displayed in the Workspace pane along with flags reflecting their status The following flags can appear next to the chunk name R Referenced Will appear when two or more chunks are aligned with each other To move photos from one chunk to another simply select them in the list of photos on the Workspace pane and then drag and drop to the target chunk Working with chunks All operations within the chunk are carried out following the common workflow loading photographs aligning them generating dense point cloud building mesh building texture atlas exporting 3D model and so on 34 Automation Note that all these operations are applied to the active chunk When a new chunk is created it is activated automatically Save project operation saves the content of all chunks To save selected chunks as a separate project use Save Chunks command from the chunk context menu To set another chunk as active 1 Right click on the chunk title on the Workspace pane 2 Select Set Active command from the context menu To remove chunk 1 Right click on the chunk title on the Workspace pane 2 Select Remove Items command from the context menu Aligning chunks After the partial 3D models are built in several chunks they can be merged together Before merging chunks they need to be aligned To align separate chunks 1 Select Align Chunks command from the Workflow menu 2 Inthe Align Chunks dialog box select chunks to be ali
12. is important in the setups where the object of interest 1s not static with respect to the scene like when using a turn table to capture the photos Masking may be also useful when the object of interest occupies only a small part of the photo In this case a small number of useful matches can be filtered out mistakenly as a noise among a much greater number of matches between background objects Building dense point cloud While building dense point cloud masked areas are not used in the depth maps computation process Masking can be used to reduce the resulting dense cloud complexity by eliminating the areas on the photos that are not of interest Masked areas are always excluded from processing during dense point cloud and texture generation stages Let s take for instance a set of photos of some object Along with an object itself on each photo some background areas are present These areas may be useful for more precise camera positioning so 1t 1s better to use them while aligning the photos However impact of these areas at the building dense point cloud is exactly opposite the resulting model will contain object of interest and its background Background geometry will consume some part of mesh polygons that could be otherwise used for modeling the main object Setting the masks for such background areas allows to avoid this problem and increases the precision and quality of geometry reconstruction 24 Editing Building textu
13. obtain more accurate camera position estimates Lower accuracy setting can be used to get the rough camera positions in a shorter period of time While at High accuracy setting the software works with the photos of the original size Medium setting cause image downscaling by factor of 4 2 times by each side and at Low accuracy source files are downscaled by further 4 times Pair preselection The alignment process of large photo sets can take a long time A significant portion of this time period 1s spent on matching of detected features across the photos Image pair preselection option may speed up this process due to selection of a subset of image pairs to be matched In the Generic preselection mode the overlapping pairs of photos are selected by matching photos using lower accuracy setting first Additionally the following advanced parameters can be adjusted Key point limit The number indicates upper limit of feature points on every image to be taken into account during current processing stage Using zero value allows PhotoScan to find as many key points as possible but it may result in a big number of less reliable points Tie point limit The number indicates upper limit of matching points for every image Using zero value doesn t apply any tie point filtering Constrain features by mask When this option is enabled features detected in the masked image regions are discarded For additional information on the usage of masks please refe
14. procedure calculates intrinsic and extrinsic camera parameters based on the tie points left after editing procedure Providing that outliers have been removed the estimates will be more accurate In addition this step involves estimation of a number of intrinsic camera parameters which are fixed at the alignment step aspect skew and distortion parameters pl p2 k4 To optimize camera alignment he Choose P Optimize Cameras command fron the Tools menu 2 In Optimize Camera Alignment dialog box check camera parameters to be optimized Click OK button to start optimization 3 After optimization is complete estimated intrinsic camera parameters can be inspected on the Adjusted tab of the Camera Claibration dialog available from the Tools menu Note e The model data if any is cleared by the optimization procedure You will have to rebuild the model geometry after optimization 23 Chapter 5 Editing Using masks Overview Masks are used in PhotoScan to specify the areas on the photos which can otherwise be confusing to the program or lead to incorrect reconstruction results Masks can be applied at the following stages of processing e Alignment of the photos e Building dense point cloud e Building 3D model texture Alignment of the photos Masked areas can be excluded during feature point detection Thus the objects on the masked parts of the photos are not taken into account while estimating camera positions This
15. recommended to decimate the model down to 100 000 200 000 polygons for exporting in PDF and to 100 000 or even less for displaying in Google Earth and alike tools To decimate 3D model 1 Select Decimate Mesh command from the Tools menu 2 Inthe Decimate Mesh dialog box specify the target number of polygons which should remain in the final model Click on the OK button to start decimation 30 Editing 3 The progress dialog box will appear displaying the current processing status To cancel processing click on the Cancel button i Note e Texture atlas is discarded during decimation process You will have to rebuild texture atlas after decimation is complete Close Holes tool Close Holes tool provides possibility to repair your model if the reconstruction procedure resulted in a mesh with several holes due to insufficient image overlap for example Close holes tool enables to close void areas on the model substituting photogrammetric reconstruction with extrapolation data It is possible to control an acceptable level of accuracy indicating the maximum size of a hole to be covered with extrapolated data To close holes in a 3D model 1 Select Close Holes command from the Tools menu 2 Inthe Close Holes dialog box indicate the maximum size of a hole to be covered with the slider Click on the OK button to start the procedure 3 The progress dialog box will appear displaying the current processing status To ca
16. with this assumption If the correct focal length value differs significantly from 50 mm the alignment can give incorrect results or even fail In such cases it is required to specify initial camera calibration manually The details of necessary EXIF tags and instructions for manual setting of the calibration parameters are given in the Camera calibration section Lens distortion The distortion of the lenses being used to capture the photos should be well simulated with the Brown s distortion model Otherwise it is most unlikely that processing results will be accurate Chapter 3 General workflow Processing of images with PhotoScan includes the following main steps e loading photos into PhotoScan e inspecting loaded images removing unnecessary images e aligning photos e building dense point cloud e building mesh 3D polygonal model e generating texture e exporting results If you are using PhotoScan in the full function not the Demo mode intermediate results of the image processing can be saved at any stage in the form of project files and can be used later The concept of projects and project files is briefly explained in the Saving intermediate results section The list above represents all the necessary steps involved in the construction of a textured 3D model from your photos Some additional tools which you may find to be useful are described in the successive chapters Preferences settings Before starting
17. 31 Editing In the Gradual Selection dialog box select Connected component size criterion Select the size of isolated components to be removed using the slider You can observe how the selection changes while dragging the slider Click OK button to finalize the selection To remove the selected components use Delete Selection command from the Edit menu or click x Delete Selection toolbar button or simply press Del button on the keyboard To remove large polygons L 2 Select Gradual Selection command from the Edit menu In the Gradual Selection dialog box select Polygon size criterion Select the size of polygons to be removed using the slider You can observe how the selection changes while dragging the slider Click OK button to finalize the selection To remove the selected components use Delete Selection command from the Edit menu or click A Delete Selection toolbar button or simply press Del button on the keyboard Note that PhotoScan always selects the fragments starting from the smallest ones If the model contains only one component the selection will be empty Manual face removal Unnecessary and excessive sections of model geometry can be also removed manually To remove part of the mesh polygons manually 1 Select rectangle circle or free form selection tool using 1 Rectangle Selection 2 Circle Selection or 4 Free Form Selection toolbar buttons Make the selection using the mouse To add new
18. Agisoft PhotoScan User Manual Standard Edition Version 1 1 Agisoft PhotoScan User Manual Standard Edition Version 1 1 Publication date 2014 Copyright O 2014 Agisoft LLC Table of Contents OVETVIEW rra dass iv FHOW EIU WOT etilo iv ADOUE h MAMMA n lt N S NNA ideas iv SAA E A eoaedaseeep ates l Ss AAA II O Ir esse l OpenGL accord a E ans lun ete aes l Installation procedure di a ia A a e EA 2 Restricti ns Of the Demo anode enna E N EE E ESE 2 DC IPOE DADIOS taa atacada et ier eced 4 AAA oe atousssoncdiece paces pylceriadaa ds cua penencacentasams ylGa teenies Saaauhen ea pac uaamans ee nataetas 4 Camera setas atado cia ab te TC te aitu 4 CIBI CL Scene CUITS MENIS E nan 4 Maso PIC DIOC SSINS vera dada dec tr dica nel 4 Captura SC HAMOS ada cs 5 Restaura o io N 6 General WOLKOW a A A ie 7 Pret renees S ONES coa ra Ves obs a ra ren ce Tes aie tt tite ee toits 7 OAI PHOS TN RE ds dd a seo 7 Alomar DIOS ss a et dt aie iii 9 Buide dense point Cloud escenes in A en AA ES 11 B ldino WiC SM arias en din estiment cute decide dot 12 Butidino model texte a dos 13 Savine imermediate results ste lt dada Nadir EA 15 EXPOS es SE A ato 16 4 improvins Camera alleamentTesults uta acia 21 Camerac anda s 21 Optimization or camera AN onmi dd a dao aite 23 RENNE AAA NA 24 USAS its ar O tias 24 Baiting pomtclon dados 28 Edite model Eome y ne nn ein merde esta din ias tits id 30 O AUTOM AI AA A AAA a 34 Uoma CMOK S srta dt ar
19. Chapter 5 Editing Chapter 6 Automation describes opportunities to save up on manual intervention to the processing workflow It can take up quite a long time to reconstruct a 3D model PhotoScan allows to export obtained results and save intermediate data in a form of project files at any stage of the process If you are not familiar with the concept of projects its brief description is given at the end of the Chapter 3 General workflow In the manual you can also find instructions on the PhotoScan installation procedure and basic rules for taking good photographs 1 e pictures that provide most necessary information for 3D reconstruction For the information refer to Chapter 2 Capturing photos and Chapter 1 Installation Chapter 1 Installation System requirements Minimal configuration e Windows XP or later 32 or 64 bit Mac OS X Snow Leopard or later Debian Ubuntu 64 bit e Intel Core 2 Duo processor or equivalent e 2GB of RAM Recommended configuration e Windows XP or later 64 bit Mac OS X Snow Leopard or later Debian Ubuntu 64 bit e Intel Core 17 processor e 12GB of RAM The number of photos that can be processed by PhotoScan depends on the available RAM and reconstruction parameters used Assuming that a single photo resolution is of the order of 10 MPx 2GB RAM is sufficient to make a model based on 20 to 30 photos 12GB RAM will allow to process up to 200 300 photographs OpenCL acceleration PhotoSc
20. Specifies the source of the mask data From Alpha load masks from alpha channel of the source photos From File load masks from separate images From Background generate masks from background photos From Model generate masks based on reconstructed model Mask file names not used in From alpha mode Specifies the file name template used to generate mask file names This template can contain special tokens that will be substituted by corresponding data for each photo being processed The following tokens are supported 25 Editing filename file name of the source photo without extension fileext extension of the source photo camera camera label filenum sequential number of the mask being imported For example filename _mask png template can be used if masks are available in PNG format and have a_mask suffix Tolerance From Background method only Specifies the tolerance threshold used for background differencing Tolerance value should be set according to the color separation between foreground and background pixels For larger separation higher tolerance values can be used Editing masks Modification of the current mask is performed by adding or subtracting selections A selection is created with one of the supported selection tools and is not incorporated in the current mask until it is merged with a mask using Add Selection or Subtract Selection operations To edit the mask 1 Open the pho
21. Workspace pane all elements comprising the current project are displayed These elements can include e List of chunks in the project e List of cameras and camera groups in each chunk e Tie points in separate chunks e Depth maps in separate chunks e Dense point clouds in separate chunks e 3D models in separate chunks Buttons located on the Workspace pane toolbar allow to e Add chunk e Add photos e Enable or disable certain cameras or chunks for processing at further stages e Remove items Each element in the list is linked with the context menu providing quick access to some common operations 39 Graphical user interface Photos pane Photos pane displays the list of photos masks in the active chunk in the form of thumbnails Buttons located on the Photos pane toolbar allow to Enable disable certain cameras Remove cameras Rotate selected photos clockwise counterclockwise Reset current photo filtering option Switch between images and masks thumbnails Increase decrease icons size or display detailed information on photos including EXIF data Console pane Console pane 1s used for Displaying auxiliary information Displaying error messages Buttons located on the pane toolbar allow Save log Clear log Note e To open any pane select a corresponding command from the View menu Menu commands File Menu Fi New Creates an empty PhotoScan project ES Open Opens PhotoScan project file Appe
22. a calibration Import formats PhotoScan Lens Calibration xml Australis Camera Parameters txt PhotoModeler Camera Calibration in1 3DM CalibCam Camera Parameters txt CalCam Camera Calibration cal Undistort formats JPG TIFF PNG BMP OpenEXR Export formats PhotoScan Lens Calibration xml Australis Camera Parameters txt PhotoModeler Camera Calibration in1 3DM CalibCam Camera Parameters txt CalCam Camera Calibration cal Intrinsic and extrinsic camera parameters Import camera positions PhotoScan xml BINGO dat Bundler out VisionMap Detailed Report txt Tie points Import not available 47 Export camera positions PhotoScan xml Bundler out CHAN files chan Boujou txt Omega Phi Kappa txt Export matches BINGO dat ORIMA txt PATB ptb Sparse dense point cloud Import not available Mesh model Import mesh Wavefront OBJ obj 3DS models 3ds COLLADA dae Stanford PLY ply STL models stl Autodesk DXF dxf Autodesk FBX fbx Universal 3D models u3d OpenCTM models Texture Import texture JPG TIFF PNG BMP OpenEXR PGM PPM Supported formats Export formats Wavefront OBJ obj Stanford PLY ply XYZ Point Cloud txt ASPRS LAS las ASTM E57 e57 Universal 3D u3d potree zip PhotoScan OC3 0c3 Adobe PDF pdf Export mesh Wavefront OBJ obj 3DS
23. a problem providing that these parts appear on other images e Good lighting is required to achieve better quality of the results yet blinks should be avoided It is recommended to remove sources of light from camera fields of view Avoid using flash The following figures represent advice on appropriate capturing scenarios Facade Incorrect Facade Correct Interior Incorrect Interior Correct Capturing photos Isolated Object Incorrect Isolated Object Correct RU a Te fy 4 Restrictions In some cases it might be very difficult or even impossible to build a correct 3D model from a set of pictures A short list of typical reasons for photographs unsuitability is given below Modifications of photographs PhotoScan can process only unmodified photos as they were taken by a digital photo camera Processing the photos which were manually cropped or geometrically warped is likely to fail or to produce highly inaccurate results Photometric modifications do not affect reconstruction results Lack of EXIF data To estimate the field of view for each photo PhotoScan uses the information saved in the EXIF part of each picture If EXIF data are available you can expect to get the best possible 3D reconstruction However 3D scene can also be reconstructed in the absence of EXIF data In this case PhotoScan assumes that focal length in 35 mm equivalent equals to 50 mm and tries to align the photos in accordance
24. a project with PhotoScan it 1s recommended to adjust the program settings for your needs In Preferences dialog General Tab available through the Tools menu you can indicate the path to the PhotoScan log file to be shared with the Agisoft support team in case you face any problems during the processing Here you can also change GUI language to the one that is most convenient for you The options are English Chinese French German Portuguese Russian Spanish On the OpenCL Tab you need to make sure that all OpenCL devices detected by the program are checked PhotoScan exploits GPU processing power that speeds up the process significantly If you have decided to switch on GPUs for photogrammetric data processing with PhotoScan it is recommended to free one physical CPU core per each active GPU for overall control and resource managing tasks Loading photos Before starting any operation it is necessary to point out what photos will be used as a source for 3D reconstruction In fact photographs themselves are not loaded into PhotoScan until they are needed So when you load photos you only indicate photographs that will be used for further processing To load a set of photos 7 Select Add Photos command from the Workflow menu or click A dd Photos toolbar button on the Workspace pane 2 In the Add Photos dialog box browse to the folder containing the images and select files to be processed Then click Open button 3 Selected phot
25. a rd toa 34 A Graphical user MEIC a ono as 38 ADDHCAUOR o AP adieu 38 Men cOn MaS E 40 HOGIDAE DUMAS ne a E anti lee een en ee eur 44 O RS as aan ca seca a tr ne ne tes AU D le 45 BD SUPPOMed Trmal St aa nn Sd ed M mit ti date tation 47 TMA SCS SR REA EA san E EEA en 47 Caneta Cal DEAUON cca re ar em der eine tri delai de res 47 InG ansic and exteimsio cametra parameters tai 4 TG OMG PENA CIA PONCE PEO o den ce nt MU nd Dit tite CS nd es 4 SbDarse dense POM COU a AAA 48 DU ES PA AT SP O ia 48 A E E A AASE EE E E es E cale 48 Cy Camera mode iae e E A AE 49 Frame Cameras A bee le der 49 111 Overview Agisoft PhotoScan is an advanced image based 3D modeling solution aimed at creating professional quality 3D content from still images Based on the latest multi view 3D reconstruction technology it operates with arbitrary images and is efficient in both controlled and uncontrolled conditions Photos can be taken from any position providing that the object to be reconstructed is visible on at least two photos Both image alignment and 3D model reconstruction are fully automated How it works Generally the final goal of photographs processing with PhotoScan is to build a textured 3D model The procedure of photographs processing and 3D model construction comprises four main stages 1 The first stage is camera alignment At this stage PhotoScan searches for common points on photographs and matches them as well as it finds the positio
26. adial distortion coefficients P P2 tangential distortion coefficients skew skew coefficient between the x and the y axis width image width in pixels height image height in pixels Frame cameras x X Z y Y Z r sqrt x y KS XC K r Kor K3r Kar Pr 17 2x2 2P xy y y l K r Kor K3r Kar Pi 17 2y 2Poxy u Cx X y skew V Cy yiy 49
27. ally this data is indicated in camera specification or can be received from some online source To indicate to the program that camera orientation parameters should be estimated based on the focal length and pixel size information 1t is necessary to set the Type parameter on the Initial tab to Auto value Camera calibration parameters Once you have tried to run the estimation procedure and got poor results you can improve them thanks to the additional data on calibration parameters To specify camera calibration parameters 1 Select Camera Calibration command from the Tools menu 2 Select calibration group which needs reestimation of camera orientation parameters on the left side of the Camera Calibration dialog box 3 Inthe Camera Calibration dialog box select Initial tab 4 Modify the calibration parameters displayed in the corresponding edit boxes 5 Set the Type to the Precalibrated value 6 Repeat to every calibration group where applicable 7 Click OK button to set the calibration Note e Alternatively initial calibration data can be imported from file using Load button on the Initial tab of the Camera Calibration dialog box In addition to PhotoScan calibration file format it is possible to import data from Australis PhotoModeler 3DM CalibCam CalCam Initial calibration data will be adjusted during the Align Photos processing step Once Align Photos processing step is finished adjusted calibration data will be d
28. an supports accelerated depth maps reconstruction due to the graphics hardware GPU exploiting NVidia GeForce 8xxx series and later ATI Radeon HD 5xxx series and later PhotoScan is likely to be able to utilize processing power of any OpenCL enabled device during Dense Point Cloud generation stage provided that OpenCL drivers for the device are properly installed However because of the large number of various combinations of video chips driver versions and operating systems Agisoft is unable to test and guarantee PhotoScan s compatibility with every device and on every platform The table below lists currently supported devices on Windows platform only We will pay particular attention to possible problems with PhotoScan running on these devices Table 1 1 Supported Desktop GPUs on Windows platform NVIDIA AMD GeForce GTX Titan Radeon R9 290x GeForce GTX 980 Radeon HD 7970 GeForce GTX 780 Radeon HD 6970 GeForce GTX 680 Radeon HD 6950 GeForce GTX 580 Radeon HD 6870 Installation NVIDIA AMD GeForce GTX 570 Radeon HD 5870 GeForce GTX 560 Radeon HD 5850 GeForce GTX 480 Radeon HD 5830 GeForce GTX 470 GeForce GTX 465 GeForce GTX 285 GeForce GTX 280 Although PhotoScan is supposed to be able to utilize other GPU models and being run under a different operating system Agisoft does not guarantee that it will work correctly i Note e OpenCL acceleration can be enabled using OpenCL tab in the Preferences dialog box Fo
29. areas of the image To make a selection with a Magic Wand tool click inside the region to be selected 26 Editing The range of pixel colors selected by Magic Wand is controlled by the tolerance value At lower tolerance values the tool selects fewer colors similar to the pixel you click with the Magic Wand tool Higher value broadens the range of colors selected Note e To add new area to the current selection hold the Ctrl key during selection of additional area e To reset mask selection on the current photo press Esc key A mask can be inverted using Invert Mask command from the Photo menu The command is active in Photo View only Alternatively you can invert masks either for selected cameras or for all cameras in a chunk using Invert Masks command from a photo context menu on the Photos pane The masks are generated individually for each image If some object should be masked out 1t should be masked out on all photos where that object appears Saving masks Created masks can be also saved for external editing or storage To export masks 1 Za 3 4 Select Export Masks command from the Tools menu In the Export Mask dialog select suitable parameters Click OK button when done Browse to the folder where the masks should be saved and select 1t The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button The following parameters can be specif
30. aximum intensity of the corresponding pixel is selected Min Intensity the photo which has minimum intensity of the corresponding pixel 1s selected Texture size count Specifies the size width amp hight of the texture atlas in pixels and determines the number of files for texture to be exported to Exporting texture to several files allows to archive greater resolution of the final model texture while export of high resolution texture to a single file can fail due to RAM limitations Additionally the following advanced parameters can be adjusted Enable color correction The feature 1s useful for processing of data sets with extreme brightness variation However please note that color correction process takes up quite a long time so it is recommended to enable the setting only for the data sets that proved to present results of poor quality Note e HDR texture generation requires HDR photos on input To improve result texture quality 1t may be reasonable to exclude poorly focused images from processing at this step PhotoScan suggests automatic image quality estimation feature Images with quality value of less than 0 5 units are recommended to be disabled and thus excluded from texture generation procedure To disable a photo use e Disable button from the Photos pane toolbar PhotoScan estimates image quality as a relative sharpness of the photo with respect to other images in the data set The value of the parameter is calculated
31. can be applied to all chunks in the Workspace to unprocessed chunks only or to the chunks selected by the user Each operation chosen in the Batch processing dialog will be applied to every selected chunk before processing will move on to the next step Batch processing can perform the following operations e Align Photos e Optimize Alignment e Build Dense Cloud e Build Mesh e Build Texture e Decimate Mesh 36 Automation Import Cameras Import Masks Export Points Export Model Export Texture Align Chunks Merge Chunks Save Project Save project after every completed operation To start batch processing 1 Ze Select Batch Process command from the Workflow menu Click Add to add the desired processing stages In the Add Job dialog select the kind of operation to be performed the list of chunks 1t should be applied to and desired processing parameters Click OK button when done Repeat the previous steps to add other processing steps as required Arrange jobs by clicking Up and Down arrows at the right of the Batch Process dialog box Click OK button to start processing The progress dialog box will appear displaying the list and status of batch jobs and current operation progress To cancel processing click the Cancel button 37 Appendix A Graphical user interface Application window General view ES a File Edit View Workflow Tools Photo ap a Ee 4 f
32. can be performed by PhotoScan For more complex editing you have to engage external 3D editor tools PhotoScan allows to export mesh edit it by another software and import it back 4 After geometry i e mesh is reconstructed it can be textured and or used for orthophoto generation Several texturing modes are available in PhotoScan they are described in the corresponding section of this manual About the manual Basically the sequence of actions described above covers most of the data processing needs All these operations are carried out automatically according to the parameters set by user Instructions on how to get through these operations and descriptions of the parameters controlling each step are explained in the corresponding sections of the Chapter 3 General workflow In some cases however additional actions may be required to get the desired results Pictures taken using uncommon lenses such as fish eye one may require preliminary calibration of optical system parameters PhotoScan enables to reestimate extrinsic and intrinsic camera parameters to be optimized for a filtered tie 1V Overview point pool Chapter 4 Improving camera alignment results covers that part of the software functionality In some capturing scenarios masking of certain regions of the photos may be required to exclude them from the calculations Application of masks in PhotoScan processing workflow as well as editing options available are described in
33. d be useful when it turns out to be hard or even impossible to generate a 3D model of the whole scene in one go This could happen for instance 1f the total amount of photographs 1s too large to be processed at a time To overcome this difficulty PhotoScan offers a possibility to split the set of photos into several separate chunks within the same project Alignment of photos building dense point cloud building mesh and forming texture atlas operations can be performed for each chunk separately and then resulting 3D models can be combined together Working with chunks 1s not more difficult than using PhotoScan following the general workflow In fact in PhotoScan always exists at least one active chunk and all the 3D model processing workflow operations are applied to this chunk To work with several chunks you need to know how to create chunks and how to combine resulting 3D models from separate chunks into one model Creating a chunk To create new chunk click on the EdAdd Chunk toolbar button on the Workspace pane or select Add Chunk command from the Workspace context menu available by right clicking on the root element on the Workspace pane After the chunk is created you may load photos in it align them generate dense point cloud generate mesh surface model build texture atlas export the models at any stage and so on The models in the chunks are not linked with each other The list of all the chunks created in the current project
34. d camera data can be imported back to PhotoScan using Import Cameras command from the Tools menu to proceed with 3D model reconstruction procedure Camera calibration and orientation data export To export camera calibration and camera orientation data select Export Cameras command from the Tools menu To export import only camera calibration data select Camera Calibration command from the Tools menu PhotoScan supports camera data export in the following formats e PhotoScan structure file format XML based e Bundler OUT file format e CHAN file format e Boujou TXT file format e Omega Phi Kappa text file format 4 Note e Camera data export in Bundler and Boujou file formats will save sparse point cloud data in the same file e Camera data export in Bundler file format would not save distortion coefficients k3 k4 Panorama export PhotoScan is capable of panorama stitching for images taken from the same camera position camera station To indicate for the software that loaded images have been taken from one camera station one should move those photos to a camera group and assign Camera Station type to it For information on camera group refer to Loading photos section To export panorama 1 Select Export Export Panorama command from the Tools menu 2 Select camera group which panorama should be previewed for 3 Choose panorama orientation in the file with the help of navigation buttons to the right of the pr
35. e Camera Calibration dialog box choose the source group on the left hand part of the dialog 3 Select photos to be moved and drag them to the target group on the left hand part of the Camera Calibration dialog box To place each photo into a separate group you can use Split Groups command available at the right button click on a calibration group name in the left hand part of the Camera Calibration dialog Camera types PhotoScan supports the following type of camera Frame camera Ifthe source data within a calibration group was shot with a frame camera for successful estimation of camera orientation parameters the information on approximate focal length pix is required Obviously to calculate focal length value in pixel it is enough to know focal length in mm along with the sensor pixel size in mm Normally this data is extracted automatically from the EXIF metadata In case source images lack EXIF data or the EXIF data is insufficient to calculate focal length in pixels PhotoScan will assume that focal length equals to 50 mm 35 mm film equivalent However if the initial guess values differ significantly from the actual focal length it is likely to lead to failure of the alignment process So if photos do not contain EXIF metadata it is preferable to specify focal length mm and sensor 21 Improving camera alignment results pixel size mm manually It can be done in Camera Calibration dialog box available from Tools menu Gener
36. e produces even more compact texture representation than the Adaptive orthophoto mode at the expense of texture quality in vertical regions Single photo The Single photo mapping mode allows to generate texture from a single photo The photo to be used for texturing can be selected from Texture from list Keep uv The Keep uv mapping mode generates texture atlas using current texture parametrization It can be used to rebuild texture atlas using different resolution or to generate the atlas for the model parametrized in the external software Texture generation parameters The following parameters control various aspects of texture atlas generation Texture from Single photo mapping mode only Specifies the photo to be used for texturing Available only in the Single photo mapping mode Blending mode not used in Single photo mode Selects the way how pixel values from different photos will be combined in the final texture Mosaic gives more quality for orthophoto and texture atlas than Average mode since it does not mix image details of overlapping photos but uses most appropriate photo 1 e the one where the pixel in question is located within the shortest distance from the image center Mosaic texture blending mode is especially useful for orthophoto generation based on approximate geometric model Average uses the average value of all pixels from individual photos 14 General workflow Max Intensity the photo which has m
37. e selector to default position based on the sparse point cloud Shows preferences dialog box Opens next photo from the list in the Photos pane Opens previous photo from the list in the Photos pane Switches to navigation mode Rectangle selection tool Intelligent Scissors selection tool Intelligent Paint selection tool Magic Wand selection tool Adds current selection to the mask Subtracts current selection from the mask Inverts current selection Inverts mask for the current photo Resets mask for the current photo Turns mask shading on or off Shows detected features used for alignment of the current photo Displays help contents Help Menu Check for Updates Activate Product de About PhotoScan Toolbar buttons General commands E New ES Open Save 3D view commands Undo E Redo 3 Navigation a _1 Rectangle Selection ka Circle Selection na T4 i Free Form Selection de Resize region Ce Rotate Region Rotate Object x Delete Selection y Crop Selection 3D view settings oo o0 Point Cloud ggg a26 Dense Cloud lb shaded gt Solid lt gt Wireframe Graphical user interface Checks if PhotoScan update is available for download Activates deactivates the product using the activation key Displays program information version number and copyright Creates a new PhotoScan project file Opens a PhotoScan project file Saves a PhotoScan pro
38. ect the Build Dense Cloud command from the Workflow menu 3 In the Build Dense Cloud dialog box select the desired reconstruction parameters Click OK button when done 4 The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button 11 General workflow Reconstruction parameters Quality Specifies the desired reconstruction quality Higher quality settings can be used to obtain more detailed and accurate geometry but require longer time for processing Interpretation of the quality parameters here is similar to that of accuracy settings given in Photo Alignment section The only difference 1s that in this case Ultra High quality setting means processing of original photos while each following step implies preprocessing image size downscaling by factor of 4 2 times by each side Additionally the following advanced parameters can be adjusted Depth Filtering modes At the stage of dense point cloud generation reconstruction PhotoScan calculates depth maps for every image Due to some factors like poor texture of some elements of the scene noisy or badly focused images there can be some outliers among the points To sort out the outliers PhotoScan has several built in filtering algorithms that answer the challenges of different projects If the geometry of the scene to be reconstructed 1s complex with numerous small details on the foreground then it is recommended to set
39. enu 2 Inthe Save As dialog box specify the desired mesh format in the Save as type combo box Select the file name to be used for the model and click Save button 3 In the opened dialog box specify additional parameters specific to the selected file format Click OK button when done To import edited mesh 1 Select Import Mesh command from the Tools menu 2 In the Open dialog box browse to the file with the edited model and click Open 4 Note e PhotoScan supports loading models in Wavefront OBJ 3DS STL COLLADA Stanford PLY Autodesk FBX Autodesk DXF OpenCTM and U3D file formats only Please make sure to select one of these file formats when exporting model from the external 3D editor 33 Chapter 6 Automation Using chunks When working with typical data sets automation of general processing workflow allows to perform routine operations efficiently PhotoScan allows to assign several processing steps to be run one by one without user intervention thanks to Batch Processing feature Manual user intervention can be minimized even further due to multiple chunk project concept each chunk to include one typical data set For a project with several chunks of the same nature common operations available in Batch Processing dialog are applied to each selected chunk individually thus allowing to set several data sets for automatic processing following predefined workflow pattern In addition multiple chunk project coul
40. erted to the TIFF files is preferred since JPG compression induces unwanted noise to the images Take images at maximal possible resolution ISO should be set to the lowest value otherwise high ISO values will induce additional noise to images Aperture value should be high enough to result in sufficient focal depth it is important to capture sharp not blurred photos Shutter speed should not be too slow otherwise blur can occur due to slight movements Object scene requirements Avoid not textured shiny mirror or transparent objects If still have to shoot shiny objects under a cloudy sky Avoid unwanted foregrounds Avoid moving objects within the scene to be reconstructed Avoid absolutely flat objects or scenes Image preprocessing PhotoScan operates with the original images So do not crop or geometrically transform 1 e resize or rotate the images Capturing photos Capturing scenarios Generally spending some time planning your shot session might be very useful e Number of photos more than required is better than not enough e Number of blind zones should be minimized since PhotoScan is able to reconstruct only geometry visible from at least two cameras e Each photo should effectively use the frame size object of interest should take up the maximum area In some cases portrait camera orientation should be used e Do not try to place full object in the image frame if some parts are missing it is not
41. eview window in the Export Panorama dialog 18 oy 6 General workflow Set exporting parameters select camera groups which panorama should be exported for and indicate export file name mask Click OK button Browse the destination folder and click Save button 3D model export To export 3D model 1 Select Export Model command from the File menu 2 Browse the destination folder choose the file type and print in the file name Click Save button 3 Inthe Export Model dialog indicate export parameters applicable to the selected file type 4 Click OK button to start export 5 The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button PhotoScan supports model export in the following formats Wavefront OBJ 3DS file format VRML COLLADA Stanford PLY STL models Autodesk FBX Autodesk DXF U3D Adobe PDF Some file formats OBJ 3DS VRML COLLADA PLY FBX save texture image in a separate file The texture file should be kept in the same directory as the main file describing the geometry If the texture atlas was not built only the model geometry is exported Extra products to export In addition to main targeted products PhotoScan allows to export several other processing results like Undistort photos 1 e photos free of lens distortions Undistort Photos command available from Export submenu of the Tools menu Depth map fo
42. gned indicate reference chunk with a double click Set desired alignment options Click OK button when done 3 The progress dialog box will appear displaying the current processing status To cancel processing click the Cancel button Aligning chunks parameters The following parameters control the chunks alignment procedure and can be modified in the Align Chunks dialog box Method Defines the chunks alignment method Point based method aligns chunks by matching photos across all the chunks Camera based method is used to align chunks based on estimated camera locations Corresponding cameras should have the same label Accuracy Point based alignment only Higher accuracy setting helps to obtain more accurate chunk alignment results Lower accuracy setting can be used to get the rough chunk alignment in the shorter time Point limit Point based alignment only The number indicates upper limit of feature points on every image to be taken into account during Point based chunks alignment Fix scale Option is to be enabled in case the scales of the models in different chunks were set precisely and should be left unchanged during chunks alignment process Preselect image pairs Point based alignment only The alignment process of many chunks may take a long time A significant portion of this time is spent for matching of detected features across the photos Image pair preselection option can speed up this process by selection of a subse
43. ht after photo alignment is completed All other export options are available after the 3D model is built If you are going to export the results point cloud mesh for the model that is not referenced please note that the resulting file will be oriented according to a default coordinate system see axes in the bottom left corner of the Model view 1 e the model can be shown differently from what you see in PhotoScan ee window To align the model orientation with the default coordinate system use Rotate object button from the Toolbar In some cases editing model geometry in the external software may be required PhotoScan supports model export for editing in external software and then allows to import it back as it is described in the Editing model geometry section of the manual Main export commands are available from the File menu and the rest from the Export submenu of the Tools menu Point cloud export To export sparse or dense point cloud 1 Select Export Points command from the File menu 16 General workflow Browse the destination folder choose the file type and print in the file name Click Save button In the Export Points dialog box select desired Type of point cloud Sparse or Dense Indicate export parameters applicable to the selected file type Click OK button to start export The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button
44. ied during mask export Export masks for Specifies whether masks should be exported for the currently opened photo active chunk or entire Workspace Current photo save mask for the currently opened photo if any Active chunk save masks for active chunk Entire workspace save masks for all chunks in the project File type Specifies the type of generated files Single channel mask image generates single channel black and white mask images Image with alpha channel generates color images from source photos combined with mask data in alpha channel Mask file names Specifies the file name template used to generate mask file names This template can contain special tokens that will be substituted by corresponding data for each photo being processed The following tokens are supported filename file name of the source photo without extension 24 Editing fileext extension of the source photo camera camera label filenum sequential number of the mask being exported For example filename _mask png template can be used to export masks in PNG format with _mask suffix i Note e When importing exporting mask for the current photo only PhotoScan will prompt for the actual image instead of image folder Mask file names parameter will not be used in this case Editing point cloud The following point cloud editing tools are available in PhotoScan e Automatic filtering based on specified cr
45. ints that are visible at least on two photos However points that are visible only on two photos are likely to be located with poor accuracy Image count filtering enables to remove such unreliable points from the cloud 28 Editing To remove points based on specified criterion l Switch to Point Cloud view mode using 99 Point Cloud toolbar button Select Gradual Selection command from the Edit menu In the Gradual Selection dialog box specify the criterion to be used for filtering Adjust the threshold level using the slider You can observe how the selection changes while dragging the slider Click OK button to finalize the selection To remove selected points use Delete Selection command from the Edit menu or click Delete Selection toolbar button or simply press Del button on the keyboard Filtering points based on applied masks To remove points based on applied masks 1 OGC Switch to Dense Cloud view mode using 8e Dense Cloud toolbar button Choose Select Masked Points command from the Dense Cloud submenu of the Tools menu In the Select Masked Points dialog box indicate the photos whose masks to be taken into account Adjust the edge softness level using the slider Click OK button to run the selection procedure To remove selected points use Delete Selection command from the Edit menu or click X Delete Selection toolbar button or simply press Del button on the keyboard Tie point per photo limit Tie point
46. isplayed on the Adjusted tab of the Camera Calibration dialog box If very precise calibration data is available to protect it from recalculation one should check Fix calibration box In this case initial calibration data will not be changed during Align Photos process Adjusted camera calibration data can be saved to file using Save button on the Adjusted tab of the Camera Calibration dialog box Calibration parameters list fx fy Focal length in x and y dimensions measured in pixels CX CY Principal point coordinates 1 e coordinates of lens optical axis interception with sensor plane skew Skew transformation coefficient k1 k2 k3 k4 Radial distortion coefficients 22 Improving camera alignment results pl p2 Tangential distortion coefficients Optimization of camera alignment During photo alignment step PhotoScan automatically finds tie points and estimates intrinsic and extrinsic camera parameters However the accuracy of the estimates depends on many factors like overlap between the neighboring photos as well as on the shape of the object surface Thus it is recommended to inspect alignment results in order to delete tie points with too large reprojection error 1f any Please refer to Editing point cloud section for information on point cloud editing Once the set of tie points has been edited it is necessary to run optimization procedure to reestimate intrinsic and extrinsic camera parameters Optimization
47. iterion sparse cloud only e Automatic filtering based on applied masks dense cloud only e Reducing number of points in cloud by setting tie point per photo limit sparse cloud only e Manual points removal 4 Note e Point cloud editing operation can be undone redone using Undo Redo command from the Edit menu Filtering points based on specified criterion In some cases it may be useful to find out where the points with high reprojection error are located within the sparse cloud or remove points representing high amount of noise Point cloud filtering helps to select such points which usually are supposed to be removed PhotoScan supports the following criteria for point cloud filtering Reprojection error High reprojection error usually indicates poor localization accuracy of the corresponding point projections at the point matching step It is also typical for false matches Removing such points can improve accuracy of the subsequent optimization step Reconstruction uncertainty High reconstruction uncertainty is typical for points reconstructed from nearby photos with small baseline Such points can noticeably deviate from the object surface introducing noise in the point cloud While removal of such points should not affect the accuracy of optimization it may be useful to remove them before building geometry in Point Cloud mode or for better visual appearance of the point cloud Image count PhotoScan reconstruct all the po
48. ject file Undo the last editing operation Redo the previously undone editing operation Navigation tool Rectangle selection tool Circle selection tool Free form selection tool Volume selection tool Volume rotation tool Model rotation tool Removes selected faces points Crops selected faces points Displays sparse point cloud reconstructed during image alignment Displays dense point cloud model Displays 3D model in the shaded mode Displays 3D model in the solid mode Displays 3D model in the wireframe mode 44 Graphical user interface 3D view settings Textured D Show Cameras Show Aligned Chunks O Reset View Photo view commands J Undo qu Redo 3 Navigation yl Rectangle Selection oa Intelligent Scissors iN Intelligent Paint AR Magic Wand Add Selection ON CET Invert Selection e Rotate Right Je amp Rotate Left FE Zoom In Zoom Out Turn Shading On Off od oo View Points Hot keys General Create new project Save project Load project Full Screen 45 Displays 3D model in the textured mode Shows hides camera positions reconstructed during image alignment Shows hides aligned chunks Resets model view Undo the last mask editing operation Redo the previously undone mask editing operation Switches to the navigation mode Rectangle selection tool Intelligent scissors tool Intelligen
49. limit parameter could be adjusted before Align photos procedure The number indicates upper limit of matching points for every image Using zero value doesn t apply any tie point filtering The number of tie points can also be reduced after the alignment process with Tie Points Thin Point Cloud command available from Tools menu As a results sparse point cloud will be thinned yet the alignment will be kept unchanged Manual points removal Incorrect points can be also removed manually To remove points from a point cloud manually 1 oo Switch to Sparse Cloud view mode using 89 Point Cloud toolbar button or to Dense Cloud view mode gua using 04 Dense Cloud toolbar button Select points to be removed using 1 Rectangle Selection Circle Selection or Cs Free Form Selection tools To add new points to the current selection hold the Ctrl key during selection of additional points To remove some points from the current selection hold the Shift key during selection of points to be removed 29 Editing To delete selected points click the x Delete Selection toolbar button or select Delete Selection command from the Edit menu To crop selection to the selected points click the y Crop Selection toolbar button or select Crop Selection command from the Edit menu Editing model geometry The following mesh editing tools are available in PhotoScan e Decimation tool e Close Holes tool e Automatic filtering based on specified criterion
50. models 3ds COLLADA dae Stanford PLY ply STL models stl Autodesk DXF dxf Autodesk FBX fbx Universal 3D models u3d VRML models wrl Adobe PDF pdf Export texture JPG TIFF PNG BMP OpenEXR PGM PPM Appendix C Camera models Agisoft PhotoScan supports parametric lens distortion model that assumes a central projection camera Non linear distortions are modeled using Brown s distortion model A camera model specifies the transformation from point coordinates in the local camera coordinate system to the pixel coordinates in the image frame The local camera coordinate system has origin at the camera projection center The Z axis points towards the viewing direction X axis points to the right Y axis points down The image coordinate system has origin at the top left image pixel whith the center of the top left pixel having coordinates 0 5 0 5 The X axis in the image coordinate system points to the right Y axis points down Image coordinates are measured in pixels Equations used to project a points in the local camera coordinate system to the image plane are provided below for each supported camera model The following definitions are used in the equations X Y Z point coordinates in the local camera coorinate system u v projected point coordinates in the image coordinate system in pixels fx fy focal lengths Cx Cy principal point coordinates K Ko Ka Kg r
51. n of the camera for each picture and refines camera calibration parameters As a result a sparse point cloud and a set of camera positions are formed The sparse point cloud represents the results of photo alignment and will not be directly used in the further 3D model construction procedure except for the sparse point cloud based reconstruction method However it can be exported for further usage in external programs For instance the sparse point cloud model can be used in a 3D editor as a reference On the contrary the set of camera positions is required for further 3D model construction by PhotoScan 2 The next stage is building dense point cloud Based on the estimated camera positions and pictures themselves a dense point cloud is built by PhotoScan Dense point cloud may be edited prior to export or proceeding to 3D mesh model generation 3 Another stage is building mesh PhotoScan reconstructs a 3D polygonal mesh representing the object surface based on the dense point cloud Additionally there is a Point Cloud based method for fast geometry generation based on the sparse point cloud alone Generally there are two algorithmic methods available in PhotoScan that can be applied to 3D mesh generation Height Field for planar type surfaces Arbitrary for any kind of object Having built the mesh it may be necessary to edit it Some corrections such as mesh decimation removal of detached components closing of holes in the mesh etc
52. ncel processing click on the Cancel button Note e The slider allows to set the size of a hole in relation to the size of the whole model surface Polygon filtering on specified criterion In some cases reconstructed geometry may contain the cloud of small isolated mesh fragments surrounding the main model or big unwanted polygons Mesh filtering based on different criteria helps to select polygons which usually are supposed to be removed PhotoScan supports the following criteria for face filtering Connected component size This filtering criteria allows to select isolated fragments with a certain number of polygons The number of polygons in all isolated components to be selected is set with a slider and is indicated in relation to the number of polygons in the whole model The components are ranged in size so that the selection proceeds from the smallest component to the largest one Polygon size This filtering criteria allows to select polygons up to a certain size The size of the polygons to be selected is set with a slider and is indicated in relation to the size of the whole model This function can be useful for example in case the geometry was reconstructed in Smooth type and there is a need to remove extra polygons automatically added by PhotoScan to fill the gaps these polygons are often of a larger size that the rest To remove small isolated mesh fragments 1 Select Gradual Selection command from the Edit menu
53. nd Appends existing PhotoScan project file to the m o current one Save Saves PhotoScan project file Save Ags Saves PhotoScan project file with a new name Export Model Saves 3D model Export Points Saves sparse dense point cloud 40 Graphical user interface File Menu Upload Model Exit Edit Menu e Undo qu Redo Delete Selection Crop Selection Invert Selection Grow Selection Shrink Selection Gradual selection View Menu oo oo Point Cloud TE Dense Cloud d Shaded db solid lt gt Wireframe Textured Full Screen 16 Show Cameras El Show Region Show Trackball O Show Info Predefined views Perspective Orthographic Stereo Mode 41 Uploads reconstructed model to one of the supported web sites Quits the application Prompts to save any unsave changes applied to the current project Undo the last editing operation Redo the previously undone editing operation Removes selected faces from the mesh or selected points from the point cloud Crops selected faces points Inverts current selection Grows current selection Shrinks current selection Selects faces points based on the specified criterion Displays sparse point cloud reconstructed during photo alignment Displays dense point cloud Displays 3D model in the shaded mode Displays 3D model in the solid mode Displays 3D model in the wireframe mode Displays 3D model in the textured mode Switches to
54. of chunks in the project and their content You can save the project at the end of any processing stage and return to it later To restart work simply load the corresponding file into PhotoScan Project files can also serve as backup files or be used to save different versions of the same model Note that since PhotoScan tends to generate extra dense point clouds and highly detailed polygonal models project saving procedure can take up quite a long time You can decrease compression level to speed up the saving process However please note that it will result in a larger project file Compression level setting can be found on the Advanced tab of the Preferences dialog available from Tools menu Project files use relative paths to reference original photos Thus when moving or copying the project file to another location do not forget to move or copy photographs with all the folder structure involved as well Otherwise PhotoScan will fail to run any operation requiring source images although the project file including the reconstructed model will be loaded up correctly Alternatively you can enable Store absolute image paths option on the Advanced tab of the Preferences dialog available from Tools menu Exporting results PhotoScan supports export of processing results in various representations sparse and dense point clouds camera calibration and camera orientation data mesh etc Point clouds and camera calibration data can be exported rig
55. os will appear on the Workspace pane General workflow i Note e PhotoScan accepts the following image formats JPEG TIFF PNG BMP PPM OpenEXR and JPEG Multi Picture Format MPO Photos in any other format will not be shown in the Add Photos dialog box To work with such photos you will need to convert them in one of the supported formats If you have loaded some unwanted photos you can easily remove them at any moment To remove unwanted photos 1 On the Workspace pane select the photos to be removed 2 Right click on the selected photos and choose Remove Items command from the opened context menu or click Men Items toolbar button on the Workspace pane The selected photos will be removed from the working set Camera groups If all the photos or a subset of photos were captured from one camera position camera station for PhotoScan to process them correctly it is obligatory to move those photos to a camera group and mark the group as Camera Station It is important that for all the photos in a Camera Station group distances between camera centers were negligibly small compared to the camera object minimal distance 3D model reconstruction will require at least two camera stations with overlapping photos to be present in a chunk However it is possible to export panoramic picture for the data captured from only one camera station Refer to Exporting results section for guidance on panorama export Alternatively camera grou
56. p structure can be used to manipulate the image data in a chunk easily like applying Disable Enable functions to the whole cameras in a group at once To move photos to a camera group 1 On the Workspace pane or Photos pane select the photos to be moved 2 Right click on the selected photos and choose Move Cameras New Camera Group command from the opened context menu 3 A new group will be added to the active chunk structure and selected photos will be moved to that group 4 Alternatively selected photos can be moved to a camera group created earlier using Move Cameras Camera Group Group_name command from the context menu To mark group as camera station right click on the camera group name and select Set Group Type command from the context menu Inspecting loaded photos Loaded photos are displayed on the Workspace pane along with flags reflecting their status The following flags can appear next to the photo name NC Not calibrated Notifies that the EXIF data available is not sufficient to estimate the camera focal length In this case PhotoScan assumes that the corresponding photo was taken using 50mm lens 35mm film equivalent General workflow If the actual focal length differs significantly from this value manual calibration may be required More details on manual camera calibration can be found in the Camera calibration section NA Not aligned Notifies that external camera orientation parameters were not es
57. polygons to the current selection hold the Ctrl key during selection of additional polygons To remove some polygons from the current selection hold the Shift key during selection of polygons to be excluded To delete selected polygons click the A Delete Selection toolbar button or use Delete Selection command from the Edit menu To crop selection to the selected polygons click the F Crop Selection toolbar button or use Crop Selection command from the Edit menu To grow or shrink current selection 1 To grow current selection press PageUp key in the selection mode To grow selection by even a larger amount press PageUp while holding Shift key pressed To shrink current selection press PageDown key in the selection mode To shrink selection by even a larger amount press PageDown while holding Shift key pressed Fixing mesh topology PhotoScan is capable of basic mesh topology fixing 32 Editing To fix mesh topology 1 Select View Mesh Statistics command from the Tools menu 2 In the Mesh Statistics dialog box you can inspect mesh parameters If there are any topological problems Fix Topology button will be active and can be clicked to solve the problems 3 The progress dialog box will appear displaying the current processing status To cancel processing click on the Cancel button Editing mesh in the external program To export mesh for editing in the external program 1 Select Export Model command from the File m
58. r any image Export Depth command available from photo context menu 19 General workflow PhotoScan supports direct uploading of the models to the Sketchfab and Verold resources To publish your model online use Upload Model command from the File menu 20 Chapter 4 Improving camera alignment results Camera calibration Calibration groups While carrying out photo alignment PhotoScan estimates both internal and external camera orientation parameters including nonlinear radial distortions For the estimation to be successful it is crucial to apply the estimation procedure separately to photos taken with different cameras Once photos have been loaded in the program PhotoScan automatically divides them into calibration groups according to the image resolution and or EXIF metadata like camera type and focal length All the actions described below could and should be applied or not applied to each calibration group individually Calibration groups can be rearranged manually To create a new calibration group 1 Select Camera Calibration command from the Tools menu 2 Inthe Camera Calibration dialog box select photos to be arranged in a new group 3 In the right click context menu choose Create Group command 4 Anew group will be created and depicted on the left hand part of the Camera Calibration dialog box To move photos from one group to another 1 Select Camera Calibration command from the Tools menu 2 Inth
59. r each OpenCL device used one physical CPU core should be disabled for optimal performance e Using OpenCL acceleration with mobile or integrated graphics video chips is not recommended because of the low performance of such GPUs Installation procedure Installing PhotoScan on Microsoft Windows To install PhotoScan on Microsoft Windows simply run the downloaded msi file and follow the Instructions Installing PhotoScan on Mac OS X Open the downloaded dmg image and drag PhotoScan application to the desired location on your hard drive Installing PhotoScan on Debian Ubuntu Unpack the downloaded archive with a program distribution kit to the desired location on your hard drive Start PhotoScan by running photoscan sh script from the program folder Restrictions of the Demo mode Once PhotoScan is downloaded and installed on your computer you can run it either in the Demo mode or in the full function mode On every start until you enter a serial number 1t will show a registration box offering two options 1 use PhotoScan in the Demo mode or 2 enter a serial number to confirm the purchase The first choice is set by default so if you are still exploring PhotoScan click the Continue button and PhotoScan will start in the Demo mode The employment of PhotoScan in the Demo mode 1s not time limited Several functions however are not available in the Demo mode These functions are the following e saving the project Installation
60. r of polygons 1s likely to result in too rough mesh too huge custom number over 10 million polygons is likely to cause model visualization problems in external software Additionally the following advanced parameters can be adjusted Interpolation El If interpolation mode is Disabled it leads to accurate reconstruction results since only areas corresponding to dense point cloud points are reconstructed Manual hole filling 1s usually required at the post processing step With Enabled default interpolation mode PhotoScan will interpolate some surface areas within a circle of a certain radius around every dense cloud point As a result some holes can be automatically covered Yet some holes can still be present on the model and are to be filled at the post processing step Enabled default setting is recommended for orthophoto generation In Extrapolated mode the program generates holeless model with extrapolated geometry Large areas of extra geometry might be generated with this method but they could be easily removed later using selection and cropping tools Note e PhotoScan tends to produce 3D models with excessive geometry resolution so it is recommended to perform mesh decimation after geometry computation More information on mesh decimation and other 3D model geometry editing tools is given in the Editing model geometry section Building model texture To generate 3D model texture Le Select Build Texture command f
61. r to the Using masks section i Note e Tie point limit parameter allows to optimize performance for the task and does not generally effect the quality of the further model Recommended value is 1000 Too high tie point limit value may cause some parts of the dense point cloud model to be missed The reason is that PhotoScan generates depth maps only for pairs of photos for which number of matching points is above certain limit This limit equals to 100 matching points unless moved up by the figure 10 10 General workflow of the maximum number of matching points between the photo in question and other photos only matching points corresponding to the area within the bounding box being considered e The number of tie points can be reduced after the alignment process with Tie Points Thin Point Cloud command available from Tools menu As a results sparse point cloud will be thinned yet the alignment will be kept unchanged Point cloud generation based on imported camera data PhotoScan supports import of external and internal camera orientation parameters Thus 1f for the project precise camera data is available it is possible to load them into PhotoScan along with the photos to be used as initial information for 3D reconstruction job To import external and internal camera parameters l Select Import Cameras command from the Tools menu 2 Select the format of the file to be imported 3 Browse to the file and click Open button
62. re atlas During texture atlas generation masked areas on the photos are not used for texturing Masking areas on the photos that are occluded by outliers or obstacles helps to prevent the ghosting effect on the resulting texture atlas Loading masks Masks can be loaded from external sources as well as generated automatically from background images if such data is available PhotoScan supports loading masks from the following sources e From alpha channel of the source photos e From separate images e Generated from background photos based on background differencing technique e Based on reconstructed 3D model To import masks Le Za Select Import Masks command from the Tools menu In the Import Mask dialog select suitable parameters Click OK button when done When generating masks from separate or background images the folder selection dialog will appear Browse to the folder containing corresponding images and select it The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button The following parameters can be specified during mask import Import masks for Specifies whether masks should be imported for the currently opened photo active chunk or entire Workspace Current photo load mask for the currently opened photo if any Active chunk load masks for active chunk Entire workspace load masks for all chunks in the project Method
63. reconstructions for a given data set 12 General workflow Surface type Arbitrary surface type can be used for modeling of any kind of object It should be selected for closed objects such as statues buildings etc It doesn t make any assumptions on the type of the object modeled which comes at a cost of higher memory consumption Height field surface type 1s optimized for modeling of planar surfaces such as terrains or bas reliefs It should be selected for aerial photography processing as it requires lower amount of memory and allows for larger data sets processing Source data Specifies the source for the mesh generation procedure Sparse cloud can be used for fast 3D model generation based solely on the sparse point cloud Dense cloud setting will result in longer processing time but will generate high quality output based on the previously reconstructed dense point cloud Polygon count Specifies the maximum number of polygons in the final mesh Suggested values High Medium Low are calculated based on the number of points in the previously generated dense point cloud the ration 1s 1 5 1 15 and 1 45 respectively They present optimal number of polygons for a mesh of a corresponding level of detail It 1s still possible for a user to indicate the target number of polygons in the final mesh according to his choice It could be done through the Custom value of the Polygon count parameter Please note that while too small numbe
64. rom the Workflow menu 13 General workflow 2 Select the desired texture generation parameters in the Build Texture dialog box Click OK button when done 3 The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button Texture mapping modes The texture mapping mode determines how the object texture will be packed in the texture atlas Proper texture mapping mode selection helps to obtain optimal texture packing and consequently better visual quality of the final model Generic The default mode is the Generic mapping mode it allows to parametrize texture atlas for arbitrary geometry No assumptions regarding the type of the scene to be processed are made program tries to create as uniform texture as possible Adaptive orthophoto In the Adaptive orthophoto mapping mode the object surface 1s split into the flat part and vertical regions The flat part of the surface 1s textured using the orthographic projection while vertical regions are textured separately to maintain accurate texture representation in such regions When in the Adaptive orthophoto mapping mode program tends to produce more compact texture representation for nearly planar scenes while maintaining good texture quality for vertical surfaces such as walls of the buildings Orthophoto In the Orthophoto mapping mode the whole object surface is textured in the orthographic projection The Orthophoto mapping mod
65. t of image pairs to be matched 35 Automation Constrain features by mask Point based alignment only When this option is enabled features detected in the masked image regions are discarded For additional information on the usage of masks refer to the Using masks section i Note e Chunk alignment can be performed only for chunks containing aligned photos Merging chunks After alignment is complete the separate chunks can be merged into a single chunk To merge chunks 1 Select Merge Chunks command from the Workflow menu 2 Inthe Merge Chunks dialog box select chunks to be merged and the desired merging options Click OK button when done 3 PhotoScan will merge the separate chunks into one The merged chunk will be displayed in the project content list on Workspace pane The following parameters control the chunks merging procedure and can be modified in the Merge Chunks dialog box Merge dense clouds Defines if dense clouds from the selected chunks are combined Merge models Defines if models from the selected chunks are combined Chunks merging result i e photos point clouds and geometry will be stored in the new chunk and it may be treated as an ordinary chunk e g the model can be textured and or exported Batch processing PhotoScan allows to perform general workflow operations with multiple chunks automatically It is useful when dealing with a large number of chunks to be processed Batch processing
66. t paint tool Magic wand tool Adds current selection to the mask Subtracts current selection from the mask Inverts current selection Rotates the photo clockwise Rotates the photo counterclockwise Increases magnification Decreases magnification Turns mask shading on or off Shows hides feature points used for alignment of the photo Ctrl N Ctrl S Ctrl O F11 Graphical user interface Model View Undo only for Delete Masking and Close Holes operations Redo only for Delete Masking and Close Holes operations Switch between navigation and any other previously selected mode Switch to stereoview mode Switch between orthographic and perspective view modes Change the angle for perspective view Predefined Views Top Bottom Right Left Front Back Rotate View Rotate Up Rotate Down Rotate Left Rotate Right Photo View Next photo according to Photos pane order Previous photo according to Photos pane order Navigation mode Selection Tools Rectangle selection Intelligent scissors Intelligent paint Magic wand Add selection Subtract selection Invert selection 46 Ctrl Z Ctrl Y Space Ctrl mouse wheel 7 Ctrl 7 3 Ctrl 3 1 Ctrl 1 ON E N 00 Page Up Page Down y UNS Ctrl Shift A Ctrl Shift S Ctrl Shift I Appendix B Supported formats Images Input formats JPG TIFF PNG BMP OpenEXR PGM PPM MPO SEQ Camer
67. timated for the current photo yet Images loaded to PhotoScan will not be aligned until you perform the next step photos alignment Ea Notifies that Camera Station type was assigned to the group Aligning photos Once photos are loaded into PhotoScan they need to be aligned At this stage PhotoScan finds the camera position and orientation for each photo and builds a sparse point cloud model To align a set of photos 1 Select Align Photos command from the Workflow menu 2 Inthe Align Photos dialog box select the desired alignment options Click OK button when done 3 The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button Alignment having been completed computed camera positions and a sparse point cloud will be displayed You can inspect alignment results and remove incorrectly positioned photos 1f any To see the matches between any two photos use View Matches command from a photo context menu in the Photos pane Incorrectly positioned photos can be realigned To realign a subset of photos 1 Reset alignment for incorrectly positioned cameras using Reset Camera Alignment command from the photo context menu 2 Select photos to be realigned and use Align Selected Cameras command from the photo context menu 3 The progress dialog box will appear displaying the current processing status To cancel processing click Cancel button When the alignment step
68. to to be masked by double clicking on its name on the Workspace Photo pane The photo will be opened in the main window The existing mask will be displayed as a shaded region on the photo 2 Select the desired selection tool and generate a selection Click on Add Selection toolbar button to add current selection to the mask or Subtract Selection to subtract the selection from the mask Invert Selection button allows to invert current selection prior to adding or subtracting it from the mask The following tools can be used for creating selections r a 4 Rectangle selection tool Rectangle selection tool is used to select large areas or to clean up the mask after other selection tools were applied q Intelligent scissors tool Intelligent scissors 1s used to generate a selection by specifying 1ts boundary The boundary is formed by selecting a sequence of vertices with a mouse which are automatically connected with segments The segments can be formed either by straight lines or by curved contours snapped to the object boundaries To enable snapping hold Ctrl key while selecting the next vertex To complete the selection the boundary should be closed by clicking on the first boundary vertex A Intelligent paint tool Intelligent paint tool is used to paint a selection by the mouse continuously adding small image regions bounded by object boundaries A Magic wand tool Magic Wand tool is used to select uniform

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