STAN User Guide (Version 1.0)
Contents
1. Subsequently STAN derives in which direction the interaxial distance needs to be changed In this example the red arrow to the right indicates that the interaxial distance needs to be increased drastically If you increase the Depth Budget i e Total Parallax STAN will take this into consideration and suggest higher interaxial distances Me You can hide or show the interaxial distance advices and or the interaxial distance gauge To show the interaxial distance advices go to Options GUI and activate Interocular Show If you want to display the convergence plane gauge in the GUI activate Interocular Gauge in addition The interaxial distance gauge shows the current motor position if a connection to the rig motors has been established The colored ar rows left and right indicate in which direction the interaxial distance should be moved to in order to get an optimal result They can turn into red very bad yellow bad and green good or vanish very good The following table summarizes the different indications and resulting advices 4 3 DVS Depth Volume Adjustment Table 1 Description of the indications and advices given by STAN in order to find the best possible interaxial distance INTERAXIAL INTERAXIAL INTERAXIAL INTERASIAL INTERAXIAL INTERAXIAL Indication The Depth Volume considera bly exceeds the Depth Budget The Depth Volume exceeds the Depth Budget The Depth Volume slightly ex2. 2 5 Stereoscopic image pair The left image has been flipped vertically to compensate for flipping introduced by the mirror rig You can start using STAN now Some stereo rig configurations may require to flip both cameras verti cally and one camera horizontally S AN A Fraunhofer The Stereoscopic Analyzer re Settings GUI Fitting input Device input Raster 1920x1080_25P Flip Left Image Horizontally Vertically Flip Right Image Horizontally Vertically Swap Images Left Right R si i re ire aiiler Restart Version 1 54 1 1 Side by Side Overlay Interlaced Plot ROLL a KEYSTONE TILT spades ZOOM 0 00 0 00 0 00 0 00 100 00 EvA nys 0 0 0 0 0 0 RECTIFY CLR AUTO STATIC NEAR SCREEN PLANE FAR Figure 2 6 Vertically or horizontally flip the images when using mirror rigs Define the flipping with the settings Options Video Flip Left Image Flip Right Image As shown in Figure 2 6 you can also swap the left and right input channel If for instance the left camera is connected to the right STAN input channel and the right camera to the left STAN input channel you can use this feature to compensate for this erroneous setup 2 4 First Steps First Steps Swap Images Left Right Figure 2 7 Swap the left and right camera input on demand The changes are ap plied immediately When you change the flipping settings and or the swapping settings these are applied immediately No restar
3. ceeds the Depth Budget The Depth Volume perfectly matches the Depth Budget The Depth Volume is slightly lower than the Depth Budget The Depth Volume is lower than the Depth Budget The Depth Volume is much lower than the Depth Budget Objects might look flat or your scene contains only a single depth plane Advice Strongly reduce the interaxial distance and or increase the dis tance between stereo rig and the nearest object Reduce the interaxial distance or increase the distance between stereo rig and nearest object Slightly reduce the interaxial dis tance or increase the distance between stereo rig and nearest object Optimal interaxial distance has been found Keep shooting You might slightly increase the interaxial distance in order to take full advantage of your available Depth Budget or bring the stereo rig nearer to the scene s nearest object Increase the interaxial distance or reduce distance between the stereo rig and the nearest object in the scene Increase the Interaxial Distance or reduce the distance between stereo rig and the scene in order to bring depth into the scene e The colors of the interaxial distance arrows depend on the 3D Settings in the Options menu The Depth Volume is com pared to the Depth Budget and a corresponding suggestion is calculated 4 3 Adjusting the Convergence Angulation Beside the interaxial distance the convergence plane is the next im po
4. space The nearest object in the scene is slightly to close to the camera rig i e the dis tance of the near clipping plane falls slightly below the minimal negative parallax Slight frame breaking might occur The nearest object in the scene is to close to the cam era rig i e the distance of the near clipping plane falls slightly below the minimal negative parallax Frame breaking might occur Strongly reduce the amount of angulation i e bring the cam eras in a more parallel position Use the HIT to shift the con vergence plane in direction of the far clipping plane Reduce the amount of angula tion i e bring the cameras in a more parallel position Use the HIT to shift the convergence plane in direction of the far clipping plane Slightly reduce the amount of angulation i e bring the cam eras in a more parallel position Use the HIT to shift the con vergence plane in direction of the far clipping plane Optimal convergence distance has been found Keep shoot ing Slightly increase the amount of angulation i e bring the cam eras in a more convergent posi tion Use the HIT to shift the convergence plane in direction of the near clipping plane Increase the amount of angula tion i e bring the cameras in a more convergent position Use the HIT to shift the conver gence plane in direction of the near clipping plane 4 6 Depth Volume Adjustment _3 The nearest object
5. 4 4 Horizontal Image Translation HIT Sensor Shift 4 7 4 5 Visualization of the Depth Structure cceeeeeeeeeeeeeeeees 4 8 5 Contents Color Adjustment Assistance ccceeseeeeesseeeeeeeeeeeeees 5 1 5 1 Color Temperature Assistance ccccceeeeeeeeeeeeeeeeeeeeeeeaes 5 1 52 Bigntness FSSI5 a Ce sara acten aus aceon seencene den seen cauncaen ce sdereaeeess 5 2 Electronic Image Alignment cccceeeeeeeeeeeeeeeeeeeeees 6 1 PPD CNG N seson raresa E EE 7 1 PA PAOS OUPO rere e eee eee eee 7 1 Toe WORDE DIECON eieren eei ar EEN E 7 1 Aa Conis MESEN 2c seer 7 2 7 3 1 Width and Height of the GUI aasssssnnnnnnsseessnnnnneeeeeneenrrnnn 7 2 7 3 2 Side by Side HD SDI Input 00 0 cccceeeeeeeeeeeeeeeeeentteee 7 2 keno AUTORI e E oem sibetnnneamentetane tees 7 2 734 Motor Control ssnin ano nEn E 7 3 Taa AOE ea E 7 3 7 3 0 PUNO COMV CPCI CC cringe tees rs tases ee a 7 3 7 3 7 Depth Plane Parallax Range cceeeeeeeeeeeeeeeeeeetenees 7 4 7 3 8 STAN Processing Speed eeeceeeeeeeeeeeeeeeeeeeeeennenees 7 4 Introduction The STAN Stereoscopic Analyzer is an assistance system for stereo shootings and 3D productions An image based scene analysis esti mates in real time the stereo geometry of the two cameras in order to allow an optimal alignment of the cameras and lens settings directly on the set It automatically eliminates undesired vertica
6. 7 3 8 Appendix stan motor MinConvergenceNormalizedET stan motor MaxConvergenceNormalizedET The motor speed can be controlled with stan gt motor AutoConvergenceAdjustmentSpeed gt 0 01 0 1 Depth Plane Parallax Range In the GUI the Depth Bar shows the colored bar in a range between stan depthrange MinShownParallax stan depthrange MaxShownParallax The values are represented in percent of the image width STAN Processing Speed There are different settings to optimize the update rate of the GUI the feature detector and the calibration precision Resolution The resolution of the image in the GUI can be changed by stan gt dialog gt GuiSubsamplingFactor gt 1 2 1 high resolution slower visualization 2 lower resolution faster visualization Feature Detection Precision The precision of the feature detection can be steered by stan gt algo SubsamplingFactor gt 1 2 1 high precision slower processing 2 lower precision faster processing Feature Detection Precision Other Parameters Additionally you can change other precision parameters of the fea ture detector stan gt algo gt SamplingDistance gt 1 2 3 1 high precision slower processing Appendix 2 moderate precision faster processing 3 low precision very fast processing stan algo MaxFeatures 1000 10000 1000 low number of feature
7. For a robust meas urement of the Y error please make sure that STAN can find objects in different planes If in doubt you can check if STAN finds feature points in different depth planes by using the Side by Side view mode with activated Feature Points display We also recommend to minimize all other errors e g Roll Vertical Keystone Zoom etc before minimizing the Y Offset This will yield to more robust meas urements If you have an interaxial distance of 100 mm and STAN indi cates a Y error of 1 your cameras are 1 mm off in height You cannot perform a Y error measurement with zero in teraxial distance For a robust measurement you need an ob ject tracked by the feature point detector near the camera and also an object which is far away Zoom Level Adjustment 00 100 3 A Zoom Level other than 100 indicates a mismatch between the two cameras focal lengths i e the two magnification factors of the lenses are not identical STAN measures the ratio between the two focal lengths and displays it in percent To minimize the error change the magnification factor of one of the two lenses i e the zoom level In case of fixed focal length lenses you might try another pair of lenses which might have better matching focal lengths Alternatively you can move one camera along the optical axis However this intro duces a small perspective error which can be neglected in most cases Try to bring the Zoom Level in a regi
8. To reduce the Vertical offset you can adjust the tilt of one or both cameras Ifyou have a vertical disparity of 1 and an image height of 1080 pixel you would have around 10 pixel of vertical offset 3 1 3 Keystone Error Adjustment KEYSTONE 0 07 The Keystone error is induced by a convergent camera geometry During rig calibration one aims to bring both cameras in a parallel geometry The cameras are parallel when the Keystone error van ishes When the Keystone error vanishes the two cameras are in parallel position 3 1 4 Tilt Keystone Error Adjustment TILT KETSTONE 0 08 A Tilt Keystone error indicates the presence of a strong tilt error Similar to a convergence angle a camera tilt also yields to a keystone This effect can be observed for instance when a projector displays an 39 3 1 5 3 1 6 Calibrating your Stereo Rig image onto a wall and the optical axis is not perpendicular to that wall However the Tilt Keystone error is usually very small and van ishes automatically when adjusting the Vertical offset Y Offset Adjustment TOF F SET 2 2 The Y Offset indicates a height difference between the two cameras The result is measured in percent and refers to the ratio of height er ror and interaxial distance If you have an interaxial distance of 100 mm and STAN indicates a Y error of 1 your cameras are 1 mm off in height STAN performs an image based measurement
9. VvV A Rohde amp Schwarz Company Accessory STAN The Stereoscopic Analyzer Version 2 10 User Guide Document Version 1 0 Copyright 2011 by DVS Digital Video Systems GmbH a Rohde amp Schwarz company Hanover All rights reserved The manuals as well as the soft and or hardware described here and all their constituent parts are protected by copyright Without the express permission of DVS Digital Video Systems GmbH any form of use which goes beyond the narrow bounds prescribed by copyright legislation is prohib ited and liable to prosecution This particularly applies to duplication copying translation processing evaluation publishing and storing and or processing in an electronic system Specifications and data may change without notice We offer no guarantee that this documenta tion is correct and or complete In no event shall DVS Digital Video Systems GmbH be liable for any damages whatsoever including without limitation any special indirect or consequential dam ages and damages resulting from loss of use data or profits or business interruption arising out of the use of or inability to use the hardware software and or manual materials Those parts of this documentation that describe optional software or hardware features usually contain a corresponding note Anyway a lack of this note does not mean any commitment from DVS Digital Video Systems GmbH Any product names mentioned in this documentation m
10. an be found in chapter Appen dix Please note that some video equipment cannot distinguish be tween a psF raster progressive scan mode using two fields as done in interlaced mode and an interlaced raster psF rasters are widely used by Sony cameras but are not specified in SMPTE 292M 2 3 Adjust Vertical and Horizontal Flip When using a mirror rig you will need to flip one or both cameras vertically or horizontally before you can start working with STAN Figure 2 3 shows an example of a stereo pair which needs a vertical flip to be applied on the left image The left camera image was flipped by using a mirror rig Figure 2 3 Unmodified camera signals The left image is flipped due to the use of a mirror rig while shooting the content Using the Side by Side view mode one can easily see the flipping option that is required Choose the appropriate flipping in the Options menu as shown in Figure 2 4 and Figure 2 6 In our example we need to flip the left im age vertically Flip Left Image Horizontally Vertically Flip Right Image Horizontally Vertically Figure 2 4 Select the appropriate flipping in the Options menu In our example the left image needs to be flipped vertically Changes are applied immediately After applying the flip we switch back to the Side by Side view mode to check the result of the flipping settings as illustrated in Figure 2 5 Apparently we do now have a valid stereo pair 2 3 Figure
11. ay interlaced Plot Options SCREEN PLAME FAR CONVERGENC T INTERAXIAL Figure 4 6 Sensor Shift Horizontal Image Translation HIT You can change the current HIT using a drag and drop mouse operation or by clicking on the and buttons The HIT gauge can be activated by selecting Options GUI Sensor Shift Show 4 5 Visualization of the Depth Structure A key feature of STAN is the ability to visualize the depth of the scene elements directly in the GUI This allows the stereographer to identify objects in the scene which are within or outside the desired depth volume To activate the visualization of the depth select Options Side by Side Feature Points as shown in Figure 4 7 4 8 Depth Volume Adjustment Left Right Roth Side by Side Overlay Interlaced Plot Options Figure 4 7 Feature Points are used to visualize the depth structure of the scene Green points lie within the Depth Budget as specified in Options 3D Settings menu Red points have exceeding negative parallax while violet colored points have exceeding positive parallax The color code is the same as the one that is used in the Depth Bar The feature points are colored Their color depends on their depth in the 3D scene and the chosen depth range parameters Points marked in violet have an exceeding positive parallax behind the screen plane while points marked in red indicate an exceeding negative parallax in front of the screen
12. ay be trademarks or registered trademarks of their respective owners and as such are subject to the usual statutory provisions Contents l l 1 Introduction s cccsscsessceessseesseeessseesseeeesseeesseeesseeesaees 1 1 2 First Steps csccsscsesseesseeeseeesseeeseeeeseeeeseeesseeeseeseseesstenses 2 1 2a DEVE CE IDUE DEVE rE 2 1 22 Sele MOU RASTET irine ei ee eaei 2 2 2 3 Adjust Vertical and Horizontal Flip 0 cceeseeeeeeeeeee tee 2 3 3 Calibrating your Stereo Rig scsssssssessesseeeseeeseersees 3 1 3 1 Mechanical AligNMent 0 ccccceececeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeaes 3 1 3 1 1 ROW Error Adjustment osccczsssdanssatndcncionsnassicsdatanetanraseaeaetecdies 3 5 3 1 2 Vertical Offset Adjustment 0 ccccececeeeesteeeeeeeeeeeeeeeeees 3 5 3 1 3 Keystone Error Adjustment c ceeeeeeeeeeeeeeteeeeeeees 3 5 3 1 4 Tilt Keystone Error Adjustment ccccceeeeeeeeeeeeeeeeeeees 3 5 3 1 5 Y Offset Adjustment ccccccccesseeeeeeeeeeeeseeaeeeeseeeeeeeeaaees 3 6 3 1 6 Zoom Level Adjustment ccccceseeeeeeeeeeeeeesaesseeeeeeeeeees 3 6 32 CUDAN OPUN aceiren e ar nR EES 3 7 4 Depth Volume Adjustment csssccsssessseeessreeesseeees 4 1 4 1 Measuring the Depth Volume cceeeeeeeeeeeeeeeeeeeeeeees 4 1 4 2 Adjusting the Interaxial Distance Stereo Baseline 4 2 4 3 Adjusting the Convergence Angulation 0e 4 4
13. ay mode can be used to get a visual feedback of the quality of the mechanical alignment Red or cyan lines around horizontal ob ject borders in the image are clear indicators for the presence of vertical disparities and thus for a poor mechanical alignment The Anaglyph Overlay mode is widely used to assist the calibration of the stereo rig Red and cyan borders indicate differences between the left and the right image This can be used to identify vertical dis parities indicating a missing calibration of the stereo rig Moreover one can easily detect horizontal disparity and especially the conver gence plane This assists the stereographer to choose the right con vergence angle or Horizontal Image Translation HIT One can choose between three sub options Input Program Preview These options define if the uncorrected image pair should be shown in the anaglyph overlay Input or if electronically corrected images should be shown Program and Preview Program refers to the cor 5 2 Calibrating your Stereo Rig rection parameters which are active on the output while Preview ap plies correction matrices which become active when hitting the but ton Rectify These sub options are also available for the visualization modes Dif ference and Opacity Overlay f aul y Side Overlay terlaced Plot Figure 3 3 Difference Overlay Mode The Difference Overlay Mode shows the luminance difference between the tw
14. can observe any delay be tween the two cameras as the stripes would then move with a cer tain delay je by Side Overlay intenlaced Plot Options Figure 5 3 The Stripes visualization mode can be activated in the Interlaced tab Color and aperture differences are easy to recognize in this view mode Addition ally you can find horizontal disparities in this view mode easily 5 3 Electronic Image Alignment Even after a careful calibration residual alignment errors might occur When using fixed focal length lenses it is not possible to equalize the focal length mechanically In addition some stereo rigs do not offer the degrees of freedom to calibrate the roll or other important align ment angles STAN can perform an electronic image alignment for the Overlay modes i e Anaglyph Difference Opacity overlay and the output To control the electronic image alignment STAN has four buttons in the lower right part of the GUI as shown in Figure 6 1 eft Right Both RGB Parade Cut Off Zebra OFF Feature Points Side by Side Overlay Interlaced Plot Options OLL KEYSTONE TILT KEYSTONE 0 08 0 07 100 4 0 7 1 7 4 2 25 RECTIFY CLR AUTO STATIC NEAR SCREEN PLANE SENSOR SHIF INTEROCULAR Figure 6 1 Electronic Image Alignment Rectification The buttons and their usage are described in the following 6 1 Electronic Image Alignment RECTIFY When pressing this buttons STAN calculates the best g
15. eometric cor rections parameters once This correction applies to the output The settings will be used unless CLR clear is pressed or RECTIFY is hit again CLR Clear This button deletes the current correction parameters The original unmodified images are displayed at the output AUTO STAN constantly updates the geometrical correction parameters This is useful when using poorly calibrated zoom lenses which induce dif ferent vertical disparities depending on the zoom level STATIC Once you have calibrated your rig hit RECTIFY and then STATIC From now on STAN displays only the remaining geometrical errors af ter the electronic image alignment Use this button to check if your calibration is still valid or if you have to recalibrate your rig 6 2 Appendix This chapter details some specifications and technical details of STAN 7 1 HD SDI Input Formats 1280x720 24P 1920x1080 231 1920x1080 29 P 1280x720 59P 1920x1080 251 1920x1080 30I 1280x720 60P 1920x1080 25sF 1920x1080 30sF 7 2 Working Directory The STAN software is located in a working directory containing the executables and the data files Linux Path opt HHI STANapp Executables opt HHI STANapp bin STANapp Config file opt HHI STANapp conf stanapp config xml Windows Path C Program Files Fraunhofer HHI STANapp 7 1 Dvs Appendix Executables C Program Files Fraunhofer HHI STANapp bin Config file C Program Files Fraun
16. he Input Device click Restart 2 2 Select Input Raster In a first step the proper Input Raster needs to be chosen The Input Raster is a combination of the resolution the frame rate and the scan mode progressive or interlaced Select the Options tab and use the drop down menu to choose the Input Raster as shown in Figure 2 2 The Input Raster has to match the configuration of the Monitor Output or the Recording Output of your cameras S AN 7 Fraunhofer The Stereoscopic Analyzer i Settings GUI Fitting Input Device 1920x1080_25P Flin Left mage 1280x720_50P Stee 1280x720_59P 1280x720_60P Flip Right Image 4920x1080 23P 1920x1080_ 23 Swap Images 1920x1080_23sF 1920x1080_24P Restart required 4990 x4 080_24sF 1920x1080_ 25 Restart 1920x1080_25sF Version 1 54 1 1 Side by Side Overlay Interlaced Plot ROLL VERTICAL KEYSTONE TILT KEYSTONE ZOOM oons 6 0 3 0 08 0 04 100 2 v 3 1 0 9 RECTIFY CLR AUTO STATIC SCREEN PLANE Figure 2 2 Input Raster selection Options Video Input Raster The Options menu is automatically opened after the start of the application when no camera signal matching the current Input Raster could be detected After changing the raster click Restart After the first start STAN shows the video settings in the Options tab It is necessary to select the proper Input Raster from the cam 2 2 First Steps eras All supported Input Rasters c
17. he image width Use the slider to move the grid lines left and right The sensor shift or HIT can be used to bring the near clipping plane or the far clipping plane to convergence The grid lines can be used to countercheck the automated depth vol ume measurement However the fastest and more precise way to check the current Depth Volume is to read it right from the colored Depth Bar as shown in Figure 4 1 4 2 Adjusting the Interaxial Distance Stereo Baseline Once the current Depth Volume has been calculated you may want to adjust the interaxial distance in order to meet your Depth Budget requirements The Depth Volume is constantly measured by STAN and displayed as shown in Figure 4 1 If this number exceeds the Depth Budget STAN will give a feedback to increase or shorten the interaxial distance This illustrated in Figure 4 3 4 2 Depth Volume Adjustment S f AN Fraunhofer HHI The Stereoscopic Analyzer Video 3D Settings GUI Fitting Total Parallax in of Screen Width Minimum Negative Parallax Maximum Positive Parallax Settings apply immediately Restart Version 1 54 1 1 Side by Side Overlay Interlaced Plot Options agree TERTE PERSEE TES ISEV STON V OFFSET ZOOM l io 0 04 07 0 07 1 0 100 4 1T 0 RECTIFY CLR AUTO STATIC f 3 EEN PLANE Figure 4 3 The Depth Volume 1 7 in this example is compared to the Depth Budget Total Parallax to be defined in the Options menu
18. hofer HHI STANapp conf stanapp config xml 7 3 Config File Settings 7 3 1 7 3 2 7 3 3 Some advanced settings can only be changed in the config file You can edit the config file using a text editor Make sure that the editor saves the file as an ASCII file and not in any binary format The key words are case sensitive The config file has an XML tree structure which makes it easy to un derstand The uppermost tree element is lt stan gt The parameters are organized in sub nodes As an example the parameter for the width of the GUI windows is lt Stan gt lt gui gt lt dialog gt lt Width gt 1024 lt Width gt In the following we discuss some advanced parameters Quit STAN using Options Quit before changing config file settings The new settings will apply after the next start of the application Width and Height of the GUI stan GUI dialog Width stan GUI dialog Height Side by Side HD SDI Input stan gt grabber SideBySideInput gt true false Auto HIT stan depthrange DoAutoSensorShift gt true false STAN can automatically keep your scene within the desired Depth Budget and apply an Auto HIT To enable the Auto HIT set this set ting to true STAN will drive the settings between stan depthrange MinSensorShift stan depthrange MaxSensorShift 7 2 7 3 4 7 3 5 7 3 6 Appendix The values are represented in percent of the i
19. in the Strongly increase the amount scene is slightly to close to of angulation i e bring the the camera rig i e the dis cameras in a more convergent tance of the near clipping position Use the HIT to shift plane falls slightly below the the convergence plane in direc minimal negative parallax tion of the near clipping plane Strong frame breaking might occur An accommodation convergence conflict might occur CONVERGENCE You can hide or show the convergence plane advices and or the convergence plane gauge To show the convergence plane advices go to Options GUI and activate Angula tion Show If you want to display the convergence plane gauge in the GUI activate Angulation Gauge in addition 4 4 Horizontal Image Translation HIT Sensor Shift An alternative way to change the convergence plane is to shift the two images electronically using a Horizontal Image Translation HIT or Sensor Shift The HIT is an active GUI element you can change the current HIT using a drag and drop mouse operation or by clicking the and buttons To display the Sensor Shift in the GUI activate the button Options GUI Sensor Shift Show Figure 4 6 shows the HIT gauge in the GUI 4 7 Depth Volume Adjustment ie E iW h I Left Right Both RGA Parade Tebra OFF Feature Points TILT KEYSTONE VERTICAL ZOOM 0 04 0 07 100 4 js 1B i RECTIFY CLR AUTO STATIC cial a 2 i i l z Side by Side Overl
20. in the lowermost histogram e To get familiar with the RGB Parade select Side by Side Both and then click the RGB Parade button You can now pan the cameras and or change the iris settings and observe the reaction of the histogram 5 2 Brightness Assistance In order to shoot good 3D content it is necessary to keep the Iris set tings of the two lenses synchronized Moreover for later color grading it is necessary to avoid over saturated regions STAN offers the Zebra visualization tool which colors nearly saturated regions Zebra 70 or oversaturated regions Zebra 100 in violet Figure 5 2 illustrates this feature Zebra 70 Side by Side Figure 5 2 Brightness Assistance The Zebra button in the Side by Side menu has three states Off no visualization Zebra 70 regions are colored which achieve 70 of the maximum brightness and 100 over saturated regions are colored i e clipping occurs in these regions 5 2 L L L L L i L L L L L Color Adjustment Assistance Additional visualization modes are the Interlaced Stripes mode and the Interlaced Checkerboard mode The Stripes mode is shown in Figure 5 3 Color and aperture differences are easy to rec ognize in this view mode Additionally you can find easily horizontal disparities in this view mode Moreover the Interlaced mode is use ful when you want to check the synchrony of the two cameras When you pan the rig back and forth you
21. l disparities be tween the two views through an electronic image rectification proc ess In addition it detects the position of near and far objects in the scene derives the optimal interaxial distance and gives alerts if syn chronization problems occur The figure below shows the Graphical User Interface of the Stereo scopic Analyzer The GUI allows an easy overview about all important stereoscopic parameters The input images can be monitored in a va riety of visualization modes RGB Parade Sida by Side Overlay Interlaced Plot Optio 0 5 Figure 1 1 STAN s Graphical User Interface GUI 1 1 First Steps This chapter describes the first steps that are required to work with STAN 2 1 Select Input Device If the VENICE server has more than one HD SDI input device choose the appropriate capture board from the drop down menu Input De vice Figure 2 1 illustrates this process sS AN Fraunhofer The Stereoscopic Analyzer Video Settings GUI Fitting input Device SD Input Device Input Raster 1920x1080_25P Flip Left Image Flip Right Image Swap Images Restart required after changing one of these settings Restart d Plc Options Figure 2 1 Input Device selection Options Video Input Device 2 7 First Steps The Options menu is automatically opened after the start of the application when no camera signal matching the current Input Raster could be detected After changing t
22. mage width The update rate can be controlled with stan motor AutoSensorShiftAdjustmentSpeed 0 01 0 1 Motor Control To enable communication between STAN and the receiver box for Element Technica motors activate this feature in the config file stan modules SimulateCamMotor false stan motor ETRigControllerPresent true stan warping ETRigControllerComPort COM 1 2 3 The COM port has different naming under Linux When the connection has been established STAN can read the cur rent motor positions and display them in the INTERAXIAL gauge and the CONVERGENCE gauge Auto Interaxial stan depthrange DoAutoInterocular true Make sure to enable Motor Control first STAN will drive the motor for the interaxial distance according to the settings made in Op tions 3D Settings STAN drives the motors in a range between stan motor MinInterocularNormalizedET stan motor MaxInterocularNormalizedET The motor speed can be controlled with stan motor AutoInterocularAdjustmentSpeed 0 01 0 1 Auto Convergence stan depthrange DoAutoConvergence true Make sure to enable Motor Control first STAN will drive the motor for the convergence angle angulation according to the settings made in Options 3D Settings Make sure to enable only Auto HIT OR Auto Convergence STAN drives the motors in a range between 7 3 7 3 7
23. nefit of STAN is the intuitive and precise measurement of the current Depth Volume The value is shown in the center of the col ored Depth Bar in the lower left region of the GUI Moreover the width of the Depth Bar is proportional to the depth volume Figure 4 1 illustrates this relationship 1 7 SCREEN PLANE Figure 4 1 The Depth Bar used for measurement of the current Depth Volume The Depth Volume in this example is 1 7 of the screen width Beside the Depth Volume STAN is measuring the amount of depth before the convergence plane i e Screen Plane and behind the screen plane These numbers are shown in Figure 4 1 above the cap tions Near and Far Another way to measure the Depth Volume is to use grid lines You can overlay grid lines by pushing the Grid button on the Overlay tab The position of the grid can be moved left and right using the slider as shown in Figure 4 2 Use the sensor shift or HIT to bring an object of interest e g the nearest object to convergence Subse quently you can measure the disparity for instance of the far clipping plane A horizontal disparity of 2 corresponds to the spacing be tween two grid lines 4 7 Depth Volume Adjustment nus zi Feunhofa Anaglyph Difference Opacity trop Side by see Opty mera ed Plot Options E 0 1 ear HEAR SCREEN PLANE Figure 4 2 Grid lines applied to an Anaglyph Overlay image Each grid line corre sponds to a disparity of 2 of t
24. o images The Difference Overlay mode is also widely used to perform the mechanical calibration of the rig and to choose a proper convergence plane In the Difference Overlay mode all objects in the conver gence plane disappear These regions are displayed in grey Vertical or horizontal disparities yield to black and white edges around objects 3 3 Calibrating your Stereo Rig Figure 3 4 Opacity Overlay mode Figure 3 5 The Cut Off Area mode combined with the Side by Side view mode allows for an optical feedback of possible calibration errors In this example the right camera suffers from a 1 1 roll error The white and orange rectangles in the two images coincide with the current camera geometry 3 4 Calibrating your Stereo Rig 3 1 1 Roll Error Adjustment The Roll error refers to a roll of the right camera with respect to the left camera To reduce the roll error you can turn the appropriate knob on your stereo rig e g Quasar A good calibration yields to values within a range of 0 1 roll error e If you have a roll error of 1 and an image height of 1080 pixel you would have around 16 pixel of vertical offset at the left and right image borders In comparison a roll error does induce vertical disparities near the image center 3 1 2 Vertical Offset Adjustment The Vertical offset is the mean disparity between the left and right image It is measured in percent of the image height
25. ociated extreme values for the positive and negative parallax The maximum parallax needs to be adapted to the projected screen size in order to avoid divergent eyes while watching The mini mum parallax should take care of possible frame breaking effect and this possible use of floating windows 4 5 Depth Volume Adjustment If you have for instance a screen of 10 m width and allow 6 5 cm positive parallax you can easily calculate the maxi mum positive parallax in percent of the screen width 6 5 1000 0 65 The settings chosen in Figure 4 5 will directly affect STAN s calcula tion of the best convergence plane The respective advices are dis played as colored arrows next to the Convergence Distance gauge The following table explains the different advices Table 2 Description of the indications and advices given by STAN in order to find the best possible convergence distance Symbol CONVERGENCE CONVERGENCE CONVERGENCE CONVERGENCE CONVERGENCE CONVERGENCE The far clipping plane consid erably exceeds the allowed positive parallax Strong risk of eye divergence when shooting for a big screen The far clipping plane the allowed positive parallax Moderate risk of eye diver gence when shooting for a big screen The far clipping plane slightly exceeds the allowed positive parallax Small risk of eye divergence when shooting for a big screen The Depth Bracket is at the right position in 3D
26. on around 99 9 and 100 1 3 6 Calibrating your Stereo Rig e When STAN measures 101 0 percent Zoom Level the fo cal length of the right lens is by 1 longer than the focal length of the left lens This will induce vertical disparities of ca 5 pixels near the top and the bottom of the stereo images when using full HD resolution 3 2 Calibration Options On the Fitting tab in the Options menu you can choose which geo metric parameters are important four your calibration process In many cases Roll Vertical and Zoom are sufficient to monitor to de termine if the rig is still well calibrated or if it requires mechanical cali bration again Figure 3 6 shows the corresponding dialog in the Op tions menu which is used to enable or disable the tracking of the dif ferent geometrical parameters All parameters which are tracked will also be shown in the bottom area of the GUI S f AN Z Fraunhofer The Stereoscopic Analyzer Video 3D Settings GUI Roll Show Vertical Show Keystone Show Zoom TiltKeystone Show Y Offset Settings apply immediately Restart Version 1 54 1 1 ZOOM 100 05 RECTIFY CLR AUTO STATIC Figure 3 6 Select the geometrical parameters to track Options Fitting Roll Vertical Keystone Tilt Keystone Zoom Y Offset 3 7 Depth Volume Adjustment This chapter describes how to adjust the stereoscopic output with STAN 4 1 Measuring the Depth Volume A key be
27. plane Points marked in green lie within the Depth Budget as defined in Figure 4 5 Objects in this zone will be comfortable to watch It is rec ommended to keep all parts of the screen in the green zone i e within the Depth Budget The colors of the feature points depend on the Depth Budget defined in the menu Options 3D Settings 4 9 Color Adjustment Assistance This chapter describes how to perform a color adjustment using STAN 5 1 Color Temperature Assistance When using a mirror rig the color temperatures will slightly differ be tween the two cameras To visualize the color temperatures you can enable the RGB Parade in the Side by Side view mode as shown in Figure 5 1 O erlay interlaced Plot Options TILT KEYSTONE VERTICAL KEYSTONE ZOM 0 04 0 09 0 1 100 3 Right Both RGE Parade ut Off Pebra OFF Feature Points RECTIFY CLA AUTO STATIC INTEROCULAR Figure 5 1 RGB Parade This visualization option is useful to match the color tem peratures and or the iris settings of the two cameras 5 1 Color Adjustment Assistance The RGB Parade helps to see how the colors differ The RGB Parade consists of three histograms one for Red Green and Blue The histo gram counts the number of dark and bright pixels column by col umn For instance bright areas in the image will yield to a histogram where many pixels will be colored in the uppermost quadrant Low light regions will cause pixels
28. points fast processing 5000 high number feature points normal processing speed 10000 high number of feature points slow processing stan algo RansacIterations 100 1000 100 moderate outlier rate very fast processing 400 low outlier rate fast processing 1000 very low outlier rate moderate processing speed 7 5
29. rtant stereoscopic parameter which needs to be set with care STAN automatically calculates the position of the Depth Bracket i e the relative position of the Depth Volume to the convergence plane 4 4 DVS Depth Volume Adjustment The amount of depth in front of and behind the convergence plane are displayed as shown in Figure 4 4 0 7 4 7 NEAR SCREEN PLANE Figure 4 4 Positions of the near and far clipping planes are shown in the GUI The values are used to derive a suitable convergence plane In the Options 3D Settings menu you can specify the amount of depth you allow as positive and negative parallax Negative values in dicate a position in front of the screen plane while positive values in dicate a position behind the screen When you set the Maximum Positive Parallax as shown in Figure 4 5 to 1 0 STAN gives the re spective advice to the stereographer to make sure that the far clipping plane does not exceed that value The same goes for Minimum Negative Parallax S AN Z Fraunhofer HHI The Stereoscopic Analyzer Video 3D Settings GUI Fitting Total Parallax in of Screen Width Minimum Negative Parallax Maximum Positive Parallax Settings apply immediately Restart Version 1 54 1 1 Side by Side Overlay Interlaced Plot RONE VESICAE TILT KEYSTONE VOFFSET ZOOM is 0 05 0 07 1 0 100 4 gt RECTIFY CLR AUTO STATIC Figure 4 5 Control of the convergence plane and ass
30. t is required 2 5 Calibrating your Stereo Rig This chapter describes how to calibrate the stereo rig with STAN 3 1 Mechanical Alignment One of the main features of STAN is to provide assistance for the me chanical alignment of the rig In Figure 3 1 the results of the geomet rical analysis are illustrated In this example Roll Vertical Keystone Tilt Keystone Y Offset and Zoom settings are evaluated and dis played KEYSTONE TILT KEYSTONE 07 0 08 Figure 3 1 Displaying the parameters for the mechanical alignment To achieve an optimal mechanical alignment the red marked values in Figure 3 1 need to be calibrated to Roll 0 Vertical Offset 0 Keystone 0 Tilt Keystone 0 Y Offset 0 Zoom Level 100 In general during the setup and calibration phase you should try to get as near as possible to the above mentioned values Depending on the stereo rig that you use you may have to calibrate some values it eratively To perform the adjustment use the appropriate calibration knobs and or screws on your stereo rigs and turn them until all values are near the optimum 3 1 Calibrating your Stereo Rig In addition you might want to get a visual feedback To do so choose one of the overlay modes in the Overlay menu as shown in Figure 3 2 to Figure 3 4 Opacity terraced Plot Options L a E T ay SCREEN FLAP LAME Figure 3 2 The Anaglyph Overl
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