EyeLink Video Overlay Option User's Manual (Tracker version: 2.0)
Contents
1. 6 3 Overlay Gaze Cursors 6 3 1 video _monoc_cursor_color video _monoc cursor color lt palette index gt Sets the color of the monocular overlay gaze cursor If this is not one of the preset options in the Video Setup screen it will replace the first entry light gray in the color choices This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments Palette index 6 3 2 video binoc_ cursor colors video binoc cursor colors lt 1 gt lt r gt lt c gt Sets the colors of the binocular gaze cursors The 3 colors are the left cursor right cursors and any overlap between them Arguments lt l gt palette index of left cursor typically 214 lt r gt palette index of right cursor typically 234 lt c gt palette index of overlap between left and right cursors typically 180 EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 18 6 3 3 video _cursor_type video cursor type lt shape number gt Sets gaze cursor shape Choices are O solid or 1 hollow This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments lt shape number gt 0 for filled 1 for hollow circle 6 3 4 video cursor limit video cursor limit lt pixels gt Sets how far the gaze cursor is allowed to move outside the standard gaze area set by screen_pixel_coords For the vide overlay we want part of the gaze curso2. e A VGA to video converter CORIOscan Select see Figure 1 for the Windows display that will produce the subject display This converter has both S Video also called Y C and Composite Video output This converter requires a DC 12V 800 mA power supply the TVOne AC Adaptor e A VGA overlay device for video AVT 3170 Scan Converter see Figure 2 This converter accepts both S Video and Composite Video input This converter requires a DC 6V 1000 mA power supply the Ever Glow AC Adaptor e Two VGA cables one for each of the display and host PCs video conversion e Several S Video or composite video cables buy longer cables for future flexibility For the purpose of demonstration the user should have a good monitor with S Video or composite video inputs ready for use in analysis and setup Small monitors may be obtained from professional video suppliers or a larger high end TV monitor may be used 2 1 Wiring Connect the CORIOscan Select converter box to the Display PC see Figure 1 1 Attach the supplied VGA cable between the PC In connection and the VGA card in the computer 2 Connect the PC Out to the monitor of the Display PC 3 Plugin the 12V TVOne power adapter EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 2 We CORIO CORIOscan Figure 1 The CORIOscan Select Converter for the Display PC Similarly connect the AVT 3170 Scan Converter to the Host PC
3. lt size gt Sets size of calibration targets in video overlay mode Legal values are 7 9 11 or 13 pixels 13 is the regular calibration target size Smaller sizes are useful when the calibration display is used as a video overlay to compensate for the magnification of the overlay Arguments lt size gt 7 9 11 or 13 pixels 9 default EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 20 6 4 4 video cal backor color video cal backgr color lt palette undex gt Color of calibration background when the calibration overlay option is enabled black in normal mode Default is 156 medium gray 6 4 5 video cal target_color video cal target color lt palette undex gt Color of calibration targets when the calibration overlay option is enabled black in normal mode Default is 127 bright white Arguments lt palette index gt typically 127 6 5 Timecode Settings 6 5 1 video_timecode_mode video timecode mode lt mode gt Sets the timecode mode This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments lt mode gt 0 is off 1 is absolute 2 is trial 6 5 2 video timecode position video timecode position lt x gt lt y gt Sets position of top left of timecode display This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments lt x gt lt y gt pixel coordianted of
4. menu Use Buttons 2 and 3 to center the image Press Button 1 to switch to the Out H Width menu then use Buttons 2 and 3 to set the display width Press Button 1 to switch to the Out V Centre menu Use Buttons 2 and 3 to center the image Press Button 1 to switch to the Out V Height menu then use Buttons 2 and 3 to set the display height Continue this process press the Button 1 to select an adjustment then use the Buttons 2 and 3 until the desktop is centered and has a blank border of the proper size on your display Press the Store button on the remote control Button E to save these settings You should hear two beeps when the settings are saved 3 2 Setting up the Host Video and Calibrating Overlay Display Calibrating the overlay graphics display to an external video source and overlay device are very simple to do once the overlay device has been configured to use part of the EyeLink display A video source with a visible region typically video of a Windows desktop corresponding to the gaze coordinate system defined with the configuration command screen_pixel_coords is displayed on a video monitor in combination with graphics from the EyeLink display A box consisting of a highly visible moving pattern is then adjusted in size and position to match this region After this is done the overlay is ready to use This setting needs to be done only once unless the source video sca
5. see Figure 2 1 Attach the supplied VGA cable between the VGA In connection and the VGA card in the computer 2 Connect the VGA Out to the monitor of the Host PC 3 Plugin the 6V Ever Glow power adapter Make the connection between the display CORIOscan Select converter and the host overlay box AVT 3170 Scan 1 Have the Composite Video Out 1 of the display converter connected to the V IN of the host overlay box with a composite video cable illustrated in Figures 1 and 2 If however a S Video cable is used make the connection between S Video Out 1 of the display converter and S IN of the host overlay box 2 Set the Video Input as V IN if a composite video cable is used in the above step illustrated in Figure 2 or S IN if a S Video cable is used 3 For best overlay quality set the Overlay Key switch to BLACK Set TV System to NTSC in North America and PAL in Europe EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 3 Figure 2 The AVT 3170 Scan Converter for the Host PC Finally connect the S Out of the overlay box to an S Video input on your monitor or TV illustrated in Figure 2 If a composite video cable is used connect the V OUT to Composite input If a VCR is used it would be connected between the overlay box and the monitor 2 2 Software Installation Copy the existing EyeLink2 directory on the host
6. PC to a new folder as a backup Then copy the supplied files into the eyeLink2 exe directory These should overwrite the eyelink2 ini and the eyelink2 exe files and add a number of extra files vidovl ini and final ini The vidovl ini file contains all of the settings for using the video overlay option You may also need to check for the settings in the physical ini file to make sure that the display monitor physical dimensions and display PC gaze coordinates are properly set If changes to these default settings are required please cut and paste the commands to the final ini and make the modification in that file for the ease of future maintenance Please also make sure that you have either track exe or cal_popup exe installed on your display PC to perform calibration validation and drift correction EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 4 3 Setting up the EyeLink Video Overlay Performing the following steps are important for getting a precise alignment of the source video from the display PC and the gaze position from the Host PC If the settings have been properly saved this needs to be done only once However it is a good practice to check the settings again at the beginning of each recording session to make sure that alignment of video sources is still ok 3 1 Setting up the Video Source Display PC Performing this setup is essential to create a blank usually black border around the Windows desktop
7. image This prevents overscan clipping of edges of the image when displaying recorded sessions on TVs and also allows a blank area for the gaze cursor to be visible when outside the desktop and for the timecode display IMPORTANT NOTE Be sure to do the setup with the same monitor you will be viewing the video with as monitors and TVs vary in how much of the edges of the video can be displayed If you plan to show the recorded video on ordinary TVs at conferences for example then use this type of display for setup or you may not be able to see the edges of the Windows desktop Otherwise use a professional monitor to maximize use of the video image 1 Turn on the display PC Configure the Windows display for the resolution and refresh rate you will be using 1024x768 or lower 2 The next step is to display the source video on the TV monitor Click on the MODE button of the Host AVT 3170 Scan converter to set the mode to Video Check the green light indication on the front of the converter box This will only show the source video from the Display PC on the TV monitor 3 The AutoSet function of the CORIOscan Converter needs to be run to correctly display the image from the computer Press Autoset Button A Figure 3 on the CORIOscan remote control to preset the video parameters The image on the TV will now begin to move around the screen Once this has stopped the AutoSet function is complete 4 Press t
8. EyeLink Video Overlay Option User s Manual Tracker version 2 0 Copyright 2002 2004 SR Research Ltd EyeLink is a registered trademark of SR Research Ltd Toronto Canada EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd Table of Contents 1s WERT URL E RL AN 1 2 SYSTEM REQUIREMENTS AND CONFIGURATION 0 0 csccssssssssssssssssesssscsssesesssessssssenessesserees 2 Se Ce 2 JI SOFTWARE INSTALLATION ncn iaee e E EE AERA E AE E ea EE EEI ARA a aE 4 3 SETTING UP THE EYELINK VIDEO OVERLAY eseseseseseereroeseserceeeroroesesesoeeerosoesesecoseororseseeeeoseeee 5 3 1 SETTING UP THE VIDEO SOURCE DISPLAY PC 5 3 2 SETTING UP THE HOST VIDEO AND CALIBRATING OVERLAY DISPLAY cccccceseescsseseeeeseeseeecseeseeecseees 7 23 CONFIGURING THE EYELINK VIDEO OVERLAY ccsccsscscssesscsensesecsenseseceeneesecsenseseceeneeseceeneeneceeneeseseenees 9 3 3 1 Selecting the Gaze Cursor Jpnegranee 10 3 3 2 Setting the Timecode Depienne 10 3 3 3 Graphics OPTIONS seien cccee ts cova e Cutter ea e a aa aeea danane 11 4 USING THE EYELINK VIDEO OVERLAY seseseeeseereroesesescseeroroeseseccseerosoesesesoseerosoesesecoseesoreeseeeeee 12 Aly CAMERA SETUP ctia EE E REE EEA E RE E EEE R tad E E E aE 12 42 PRE RECORDING PREPARATIONS eege A ENESA E aSa IEE a AEE ASE aE 12 43 RECORDING AND DRIFT CORRECTION ENEE E EASE AEE AETA EEAS A E EES 13 4 4 STOPPING RECORDING AND DATA TRANSFER ssseseseserererererererererererererererererererere
9. articipant fixates stably The drift correction may fail if there is no stable fixation data or if there is a large error between the current fixation and the target item By default the maximum acceptable error value set by the online dcorr maxangle command is 5 0 Record No C Cyc lopean Drift Corr Duration sec 25 Te ma Tracking Binocular 500 Hz Pupil Like Data to No outputs enabled Title Manual recording session Figure 11 Performing an online drift correction with mouse click If the popup calibration utility is still connected to the tracker a drift correction can also be performed outside of a recording trial First set the tracker to the Camera Setup screen and press D to start drift correction you may also need to click on the blue eye icon on the Windows task bar on the display PC to maximize the popup calibration application again so that the drift correction target is visible to the participant If the data quality is not improved following the drift correction the experimenter should check the camera setup and redo calibration and validation EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 14 4 4 Stopping Recording and Data Transfer After the experiment ends the user can stop recording of eye data The EDF file can be closed by pressing the Close File button in the Output Screen see Figure 12 The EDF file can be transferred to the displa
10. eesecaeeecaseescedecseesecaeeecaeeeessecnaseeeeaenseeaeeaeees 21 6 5 2 VidEO_tiMECOAE position 21 6 5 3 yideo TMECOd DECOlOM inerse ere aeee ee EE ene ae eae deas eeaeee Snae ESETE 22 6 5 4 Video timecode ECOLOM ogis eee i e e eea E ote aE Res 22 6 6 VIDEO OVERLAY WINDOW mee nee a E E E E E EA 22 6 6 1 video window defdult amiserit ei ie E A EE E Ea A Ea 22 6 6 2 Ee 22 List of Figures Figure 1 The CORIOscan Select Converter for the Display DC 3 Figure 2 The AVT 3170 Scan Converter for the Host PC 0 eecessesssecseesecsesesceseeeceaecaeesecneeeeenaeeeeeaeeaeeneens 4 Figure 3 Some Important Buttons on the CORTOscan Remote Control 6 Figure 4 Buttons on the CORTOscan Select Converter BOX ceesssssesseecsseeeceseceeeseeseceeesecaeeeeeneseeeeaeeeeens 7 Figure 5 The Video Setup Screen eet EENEG EENEG doses 8 Figure 6 Calibrating the Overlay Display Size 9 Figure 7 Selecting the Gaze Cursor Appearance 0 ccesessescsseeeceseeseesecaeeecnecseesecnesseceaeeeesaecateseeneeneenteaes 10 Figure 8 Setting the Timecode Display 0 00 0 ccc ceesseesseseceeeeeceeeecseeeeesecaeesecnecscceaeeeeesecaessecnesseseeseeeaeeataes 10 Figure 9 Graphics Options eier AO OA A Ha A S 11 Figure 10 Opening an EDF file for Data Recording 0 eee ceeeceseeseeecseeeceeeeeceaeeeeeaecaessecnesseeeaeeeeeaeeateaes 13 Figure 11 Performing an online drift correction with mouse CLICK ee ceeeeeeeecseeeeeseceeeecereecaeeeeeneeaenes 14 Figu
11. file in the Create EDF File dialog Note This utility was programmed such that you can easily switch to your own experiment tasks it is likely that when you entered your file name the application will be minimized Click on the blue eye icon on the Windows task bar to maximize the application again Go the Camera setup screen and press the ENTER key on the host PC keyboard to transfer the camera image to the display PC Set up an experiment volunteer and perform camera setup calibration and validation as usual read the EyeLink II User Manual version 2 0 if you need more information 4 2 Pre recording Preparations Now you can switch to your own experiment task and start recording by pressing the key on the host PC If the popup calibration utility is still connected to the tracker an EDF file is already opened for data recording otherwise you will need to open a recording file on the Output Screen by clicking on the Open File button entering the file name and then pressing the ENTER key see Figure 10 In either case the user can add custom messages to the EDF file by clicking on the Add Message not shown in the example Press the Record button to start recording EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 12 Kamera Ste Set options omar all EE Les P EDF File ss Tracking Binocular 508 Hz Pupil File Data Samples a
12. he O Scan Button D Figure 3 on the remote or the middle button of the converter box Button 2 Figure 4 to make the image smaller EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 5 00 OO Figure 3 Some Important Buttons on the CORIOscan Remote Control 5 Take a look at the image of the source video on the TV monitor Ifthe image does not have a substantial black border all around it on your display including some black at the corners you will need to adjust the size of the image a You can use the remote control to set the image size Press the Pos button Button C Figure 3 then use the arrow buttons to center the image if the arrow keys don t work press the Pos button again Press the Size button Button B Figure 3 then use the arrow buttons to adjust the size of the image if the arrow keys don t work press the Size button again Press the Store button Button E Figure 3 to save these settings You should hear two beeps when the settings are saved a You can also use the manual menu buttons on the CORIOscan converter to do this adjustment To manually set the source video size with the CORIOscan menu EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 6 Figure 4 Buttons on the CORIOscan Select Converter Box Press Button 1 MENU until Screen Size appears then press Button 3 to select the Out H Centre
13. ing Figure 9 Graphics Options User drawn graphics can be displayed behind the gaze cursor during recording These graphics are also useful in video overlays and may aid analysis or serve illustrative purposes However some experiments may create bright or distracting graphics that will block the source video The Recording button can be selected to block the display of these graphics and to preserve a clean overlay EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 11 4 Using the EyeLink Video Overlay The current section outlines data recording with the EyeLink Video Overlay option assuming that you have completed the wiring and configuration discussed in the previous sections If the EyeLink software is not yet running on the host PC start it by typing CD C EYELINK2 EXE J EYELINK2 H Once the program starts up press button 5 of the overlay remote control to set the overlay box to 2X zoom Go to the Video Setup Screen to check that the Display PC source video and the EyeLink Host overlay graphics stay properly aligned Now start the popup calibration utility on the Display PC by selecting Start gt Programs gt SR Research EyeLink gt Utilities gt Popup Calibration 4 1 Camera Setup The popup calibration utility can be used to perform camera setup calibration validation and drift correction When the program starts first enter the name of the EDF
14. lack border If that Cyclopean Gaze Cursor button is disabled gaze cursors are drawn separately for each eye blue and yellow for the left eye and right eye respectively see the settings in the vidovl ini configuration file coir Mm ie O ol lel eames Figure 7 Selecting the Gaze Cursor Appearance 3 3 2 Setting the Timecode Display The timecode display is enabled by selecting a timecode mode option see Figure 8 using the buttons at the bottom of the screen use the T key to step through options The timecode display may then be positioned by dragging it with the mouse cursor to its new position It may be possible to place the timecode display above or below the video if a blank area has been left as recommended Timecode Absolute Figure 8 Setting the Timecode Display The timecode may be set to Absolute which displays the actual tracker time in milliseconds that is used for the timestamps of samples events and messages recorded in the EDF file or as real time link data This may be used to match times to a raw ASC file for example If the Trial mode is selected the timecode displays the milliseconds elapsed since the start of the trial This is defined either as the start of recording or as the time of the last SYNCTIME message EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 10 placed in the EDF file This message may also include a time offset placed before o
15. ling or overlay device settings are changed EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 7 1 Start the host PC if you haven t done that With the Overlay Box remote press the MODE button until the green light indication on the front of the converter box is at OVERLAY 2 Start the EyeLink program eyelink2 exe The EyeLink video overlay option is enabled and disabled from the Set Options screen Two buttons have been added an Enable Overlay toggle button press the O key as a shortcut and a Video Setup button press the W key as a shortcut that switches to the Video Setup screen These buttons are only available on EyeLink systems configured for video overlay support 3 Go to the Video Setup screen Press button 5 of the overlay remote control to set the overlay box to 2X zoom On the Host display note the drawing of a box with arrows see Figure 5 located just inside the top left or bottom right corner of the calibration box This corner of the box may be moved with the arrow keys of the host keyboard the mouse is not used because of the high precision required Video Setup No Connection calibration Recording ore LST roi Video Ref Pattern Binary Timecode D H HEH Digg e NE Glen Se cursor Figure 5 The Video Setup Screen While viewing the video display on the TV monitor adjust the box so that the out
16. nd Events Enter File Name Figure 10 Opening an EDF file for Data Recording 4 3 Recording and Drift Correction During recording the TV monitor will show the gaze cursor overlaid on the source video shown to the subject If the experimenter notices excessive drifts in the gaze cursor drawing a runtime drift correction can be performed if your paradigm permits There are two ways of performing an online drift correction during recording 1 If it is very likely that the subject will look at a particular point across trials a reference position for drift correction could be defined at that position This can be done by editing the value of online dcorr_refposn in the calibr ini or final ini file under c eyelink2 exe directory of the host PC When the subject is looking at the reference position pressing F9 key on the host PC will perform the drift correction 2 Alternative an online drift correction can be performed with the aid ofa mouse click Before recording add the following line to the final ini file video_click_dcorr ON EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 13 This will bring up an additional clickable drift correction button in the record screen Click on the Drift Corr button which will flash periodically if enabled Move the mouse cursor over the intended drift correction target and instruct the participant to fixate the target precisely Press the button only once when the p
17. nk tracker or included in the vidovl ini file Some are overridden by the lastrun ini file which is written after each session 6 1 Video Overlay Enable 6 1 1 video overlay available video overlay available lt YES or NO gt Sets whether EyeLink is configured for video overlay in particular NO hides the Video Overlay buttons in the Set Options screen If not set this defaults to NO so the vidovl ini file can be excluded from the distribution Arguments YES to enable video overlay in the Set Options screen NO to disable video overlay 6 1 2 video overlay on video overlay On lt OFF or ON gt Sets the state of the video overlay mode This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments OFF if video overlay mode is off ON if video overlay mode is active 6 2 Video Overlay Colors 6 2 1 video background_color video background color lt palette index gt Sets the background color for overlay this is always black 128 Arguments Palette index always black 128 EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 17 6 2 2 video border_color video border color lt palette index gt Sets the dark gray used for the area of the gaze window outside the active overlay area and for the gray box on the Video Setup screen This color should be visibly different from black but below the default keying level A palette index of 136 is standard
18. r after the SYNCTIME keyword indicating the delay in milliseconds from the start of trial to when the message was actually sent A symbol at the left side of the timecode display indicates the timecode mode A small T at the top indicated Trial mode with time elapsed since the start of recording If a SYNCTIME message has been received a U at the bottom indicates that a user defined start time is being used No symbol indicates that Absolute timecode mode is active illustrated in Figures 5 and 6 The timecode is displayed as up to 9 digits 8 digits in Trial mode with a decimal point indicating the transition between seconds and milliseconds It is unlikely that the last digit of the milliseconds will be useful however because of the timing of video displays and the nature of most overlay devices 3 3 3 Graphics Options In some cases calibration graphics need to be presented on the video display These graphics can be generated by the EyeLink overlay when the Calibration button is selected see Figure 9 For this purpose the overlay background on the Calibration Validation and Drift Correction displays is set to gray or any other color specified in the vidovl ini file to hide source video In addition all feedback graphics are suppressed within the calibration display until the end of calibration to eliminate distractions Hide Graphics Clean overlay Calibration Record
19. r to stay in this area and thus be visible so this value should be 2 the cursor diameter or 8 pixels Arguments lt pixels gt limit on motion 6 3 5 video dim mouse_fgcolor video dim_mouse fgcolor lt palette index gt Sets the color for the dimmed mouse pointer allowed inside the active overlay area Typically 140 or slightly brighter that the borfer gray Arguments lt palette index gt 140 6 3 6 video dim mouse _ bgcolor video dim mouse bgcolor lt palette index gt Sets the color for the dimmed mouse pointer allowed inside the active overlay area Typically 128 or black Arguments lt palette index gt 128 EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 19 6 4 Special Display Modes 6 4 1 video_no record graphics video no record graphics lt ON or OFF gt Whether the display of user background graphics is suppressed in Record mode This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments lt ON or OFF gt 6 4 2 video _ cal hide cursors video cal hide cursors lt ON or OFF gt Whether the special video calibration generation option is enabled This will hide cursors and feedback graphics and use a lighter background This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments lt ON or OFF gt 6 4 3 video _ cal target size video cal target Size
20. re 12 Closing ati EDF Tile 1 0 scetescoisele ace ste sig t e E A AEN 15 EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd iii 1 Introduction The EyeLink II video overlay system uses the EyeLink II tracker to generate real time overlay graphics which are superimposed on a video source and the composite output is typically recorded by a VCR or DVD recorder The video source is typically a Windows computer display using a VGA to video converter tested or a stationary scene camera A video overlay for calibration of other sources camera or VCR displayed to the subject on a video monitor can also be generated requires manual video switching at present This option is often used to provide a gaze overlay onto a dynamic stimulus display like a web browser AVI file or DVD movie The EyeLink II Video Overlay is an additional option for the EyeLink II which can be purchased with the base EyeLink II system or ata later date EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 1 2 System Requirements and Configuration This is a Hardware Installation guide section and should only be followed if you have not changed any of the scan converters memory settings The following notes assume that a Windows PC is being used as a video source and that Composite Video is used throughout A VCR is not mentioned Before you start please check that the following items are included in the EyeLink overlay option package
21. serereresererererererereres 15 5 TECHNICAL ISSUES nonsense oresoao eo re i es asise ieste 16 6 EYELINK COMMANDS FOR OVERLAY CONFIGURATION sssesessseesoersesesercceeroroeseseccseesoeoesee 17 D VIDEO OVERLAY ENABLE 522s sccacscnsssedsotssesenssesipoven suepnesest sen aedigase tasentdensoabaconsnennesbaskqessisasnesesdetqentas 17 6 1 1 video overlay available ysin eenn eaea e e Eeee i haps eN Eae 17 6 1 2 video overlay Oe EES 17 6 2 VIDEO OVERLAY COLORS P areae e EEN E A E pE E ERNE EN EA 17 6 2 1 video_background color 17 6 2 2 VIGGO borde COLOP sik Ne EE ee 18 6 3 gt OVERLAY RER ERR ee Eet 18 6 3 1 vid MONOC CUSO COLON 23 eiert ege Eileen AE ise egen AS 18 6 3 2 ideo DINOC GER COLOPS ee ee NEESS SEENEN 18 6 3 3 Vide CUPS OF UE hee Ee Dy eis og ered athena 19 6 3 4 EN 19 6 3 5 video dm mouse J color nerasta dinine aaaea alenat i aai sesia dots ionli risainia atian 19 6 3 6 yide dim mo s e hees n e e e ee ee e a EE e 19 6 4 SPECIAL DISPLAY MODES iaeoe tae aaae E E S E aE A EEEE A E A RS 20 6 4 1 video n record graphi s sorea raii a aE T Ea EaR EER S 20 6 4 2 Video cak hide Cursors adesset iian aeie i oiae E e eege deeg 20 6 4 3 Video Cal FAV SCL SIZES een isindi dees ele E lbs R ai i 20 6 4 4 video cal backet EEN siz ee deed reg ere AEN 21 6 4 5 Kleer Cl target EE 21 639 LIMECODE SETTINGS airna E E och stetassutivat sas cosa E haa Een 21 6 5 1 VideO_tiMeCOdE_MOE esse ceceseceseeseeserseesecsesecseescsecs
22. side of the moving pattern of the calibration box is on or just inside the desired area of the video see Figure 6 EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 8 Figure 6 Calibrating the Overlay Display Size Once one corner is adjusted switch to adjusting the other corner by pressing the Tab key You can return to the top left by pressing Tab again if needed The box can quickly be reset to the size of the dark gray default area by pressing the F9 key Note The overlay display adjustment needs to be done only once as long as the overlay settings haven t been changed However at the beginning of each recording session the user needs to press button 5 of the overlay remote control to set the overlay box to 2X zoom This ensures the video source of the Display PC and EyeLink display stay properly aligned 3 3 Configuring the EyeLink Video Overlay When video overlay is enabled the gaze display window of the Offline Calibration Validation Drift Correction Output and Recording screens have a black central window in the area where the video overlay is generated with the remainder of the window filled with dark gray The overlay background can also be set to gray or any other color on the Calibration Validation and Drift Correction displays to hide source video this enables the EyeLink to produce calibration targets for display on a video monitor Gaze cursors are reduced in size and ha
23. top left EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 21 6 5 3 video timecode bgcolor video timecode bgcolor lt palette index gt Color of timecode background Default is 150 gray just brighter than overlay key 6 5 4 video timecode fgcolor video timecode fgcolor lt palette index gt Color of timecode numbers Default is 127 bright white 6 6 Video Overlay Window 6 6 1 video window default video window default lt 1 gt lt t gt lt r gt lt b gt Sets the large dark gray box on the Video Setup display ised for overlay setup Also is the ocerlay window size set by pressing the F9 key Typically 205 23 586 351 for smaller 2x zoom overlay area Typically 116 35 560 360 for large overlay area Arguments 6 6 2 video window video window lt l gt lt t gt lt r gt lt b gt Sets the overlay window size and position This is updated at the end of each session to the lastrun ini file which overrides the vidovl ini file Arguments lt l gt lt t gt lt r gt lt b gt box coords EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 22
24. ve a selectable shape and color when only one eye is being tracked User drawn graphics behind the gaze cursor may be suppressed if desired to preserve a clean overlay or added to the video overlay EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 9 as desired Finally a timecode may be placed anywhere in the overlay area displaying the time from the start of the trial either from start of recording or from the last SYNCTIME message placed in the EDF file or the tracker timestamps that are being placed in the EDF file and sent with real time link data The following sections details the functions that may be performed and options set with the Video Setup screen 3 3 1 Selecting the Gaze Cursor Appearance Gaze cursors for use in the video overlay have a selectable shape and color to improve visibility see Figure 7 Gaze cursors may either be a solid circle a hollow circle or a hollow circle with a central cross Select a cursor shape by clicking on the appropriate button at the bottom of the Video Setup screen In a binocular recording if the Cyclopean Gaze Cursor button is enabled the tracker will draw a single cyclopean gaze cursor representing the average of the two eyes Several colors can be selected for a cyclopean or a monocular gaze cursor the most useful of which are yellow and white This color can be selected in the same way as cursor shape the currently selected color is indicated by a solid b
25. y PC by using the GetFile utility Start gt Programs gt SR Research EyeLink gt Utilities gt GetFile Output No Connection Screens EDF File Tracking Binocular 566 Hz Pupil File Data Samples and Events Figure 12 Closing an EDF file EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 15 5 Technical Issues Although the EyeLink display continually updates the latest gaze cursor position and time the graphics are only transferred to the overlay device at the refresh rate of the video card typically 60 or 72 Hz or every 16 7 or 13 9 milliseconds Most commercially available overlay devices use anti flicker techniques that occasionally average 2 overlay images together before applying the collected image to the video This means that some digits of the timecode may be seen as a superposition of one or more digits The first and usually the second digits of the timecode can be read which is sufficient to match to times in a recorded data file In addition this averaging of multiple overlay images means that a moving gaze cursor may be seen as multiple darker images This is never a problem during fixations and video records of eye movements are never analyzed for saccadic parameters in any case EyeLink Overlay Option User Manual 2002 2004 SR Research Ltd 16 6 EyeLink Commands For Overlay Configuration These commands may be sent by the eyecmd_printf function to the EyeLi
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