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1. Event Showslide Hideslide Keyboard LMouseButton RMouseButton Description The timestamp in ms indicating when the event occurred from the start of the recording The type of event in text format This can be either of the following Showslide Hideslide Keyboard LmouseButton RMouseButton TCPData TCPKeyPress ShowAVI The command to show the next slide in a slide show has been received by the graphics board The command to remove the active slide in a slide show has been received by the graphics board A key has been pressed Left mouse button has been pressed Right mouse button has been pressed A trigger event has been received by ClearView A trigger keypress event has been received by ClearView The command to show the next AVI movie in a AVI stimuli has been received by the graphics board An unique identifier for each event type A data field for the event The contents of this field vary depending on what type of event this is See below table As above A description of the event The contents vary depending on what type of event this is See below table Event Key 4 Data 1 Slide number s Slide number 2 ASCII code Data 2 Description Slide label Slide label Key name for key pressed Y mouse z coordinate X mouse coordinate Y mouse coordinate X mouse coordinate 50 User Manual Tobii Eye Tracker and ClearView analysis software
2. GetLastError Get error details if any function call returned error When running a study in ClearView using trigger signals the work done in ClearView is identical to how it s run up to and including clicking the Record button in the Record view of ClearView At this point an external application can send a start signal to start recording and a stop signal to stop it During recording an external application can log events which are time stamped when they reach ClearView and are inserted into the ClearView event file Also a generic event can be sent to forward slide shows which are controlled by key stroke in ClearView Analyzing data The analysis and export tools in ClearView aim to provide powerful mechanisms for gaze visualization data abstraction and to combine data from multiple sources For actual quantitative analysis the intention is that you will export appropriate data from ClearView and use other off the shelf software for analysis Excel SPSS Matlab etc Biarri zs Wi 10 x Pe Shady Settings Dye Trether Mele Pas os 0G gt e a i Recordings a Amaye B ame Qq i E E AI AE Cirip ay TET Barein ii Pat LAPD a Figure 17 The Analysis view contains tools for analysis and different types of data exports AOI definition A very useful tool for quantifying gaze data on a higher level is to use area of interest AOT analysis When using AOI analysis you can define areas of inte
3. Timing aspects of the system There are several timing aspects which are important in an eye tracking system In real time applications such as gaze contingent applications and eye based interaction latency is one of the key aspects In post recording analysis for example slide show and web studies frame rate and precision in time stamps are important Frame rates The frame rate denotes the number of gaze data points collected by the system per second All new Tobii systems run at a constant frame rate of 50 Hz For older Tobit systems such as the ET 17 and early versions of Tobit 1750 frame rates are about 35 Hz but vary over time For these systems there are several situations in which the frame rate will drop in extreme cases as low as 10 Hz e If the subject moves the head rapidly so the system has difficulty finding the subjects eyes e Ifthe subject turns away completely from the system so the eyes are lost e If the system has difficulties finding the subject s eyes for other reasons i e under conditions when the track status meter is flickering or showing a red light e Ifother applications are running on the same computer as the eye tracker server and consume a lot of resources However as soon as stable tracking is once again resumed the frame rate goes up to full speed again For most analysis and interaction applications the varying frame rate will not be an issue it occurs mostly in conditions where t
4. Accuracy in gaze estimation Measured accuracy If your experiment runs for more than five minutes and if you don t want to use a bite bar the Tobii Eye Tracker is probably the highest accuracy eye tracker available today Over large head movements and long periods of time it boasts an effective accuracy of an amazing 1 degree approx across the entire screen The detailed measures of accuracy are described more below 14 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The accuracy of an eye tracker is measured in degrees One degree of accuracy corresponds to an average error of about 1 cm between the measured and intended gaze point at 50 cm distance from the user to the screen We define the term accuracy or bias error as all deviations between the measured and intended gaze point Accuracy of the Tobit Eye Tracker varies depending on conditions such as lighting and quality of calibrations and individuals Average accuracy over a set of individuals has been tested to 0 5 degrees using standard accuracy measurement principles for eye trackers This does not include drift effects or compensation errors from larger head motions which are the main factors affecting effective accuracy or the eye tracker Accuracy has been measured by having users perform a new 16 point calibration and thereafter having them look at 64 evenly distributed points on a computer screen The
5. lighting of the subject and reflection patterns in the eyes of the subject Optical filters Optical filters are used to block sun light and other sources of interfering light Control electronics Control electronics are built into the screen to control the monitor the camera and the NIR LEDs Gaze data recording with the Tobii Eye Tracker When an application commands the Tobit Eye Tracker Server TET Server to start recording via the eye tracker library collection of gaze data begins TET Server controls the hardware finds the relevant features of the user and calculates gaze position and other important variables This is all done fully automatic by the TET Servet The TET Server starts automatically when the eye tracker computer is booted and can be found on the System Tray as a blue t with a green play symbol or a red stop symbol Right clicking the icon reveals those few options the TET Server has Starting stopping and restarting choice of hard ware e g ET 17 1750 or x50 and the choice of using an Infant AddOn illumination This is an extra piece of hardware used for tracking infants If using an x50 there are also tools for configuring the setup read more in the document How to set up the Tobu x50 11 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Start Shop Restart Hardware Config f Infant Addn x50 Gonhig Tool Device Manager About Fi
6. Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The Tobii Eye Tracker Tobu eye tracking systems are solutions for detecting and collecting eye gaze data The key characteristics of Tobu Eye Trackers are e Plug and play eye tracking All tasks relating to finding the eyes of the subject and calculating gaze positions are done fully automatically by the system To accomplish this the Tobii Eye Trackers use sophisticated hardware in combination with advanced software algorithms e Very high tracking quality The Tobu Eye Tracker provides very robust accurate and reliable data It has excellent head motion compensation and very low drift effects All tracking is binocular e No restraints on the user The system does not impose any restrictions on the user such as helmets head rests or markers This allows a natural user environment and therefore natural user behavior is captured Calibration is also quick automatic and long lasting System overview The Tobit Eye Tracker consists of hardware and software for gaze point estimation and communication with various applications The Tobit Eye Tracker requires application software to make use of the eye tracking data either by using ClearView for eye gaze analysis by using an application for eye based computer interaction or together with custom software created by yourself or someone else using the Tobit Software Development Kit The architecture is bas
7. a gaze recording It replays the gaze path overlaid on top of the stimuli whether a still image a slide show or a movie There is also the option of showing a track status meter a UserCam picture and play the audio from the recording The tool bar at the bottom of the window contains controls for playing pausing and stepping through the Gaze Replay The blue time bar is clickable and can be dragged back and forth The menus in the Gaze Replay tool contains the following File Menu Export as AVI Launches the AVI Export for the current recording see the chapter on AVI export Save Static Representation For AVI External Video and Scene stimuli this option is enabled when the replay is paused The static representation is a copy of the current movie frame which is used as background image in Hot Spot and Gaze Plot analysis Exit Believe it or not but this exits the Gaze Replay tool View Menu Trackstatus UserCam and These options shows or hides the Tool bar respective tools The Gaze Replay itself is always visible Audio Mute This turns off the sound in the replay 41 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Settings Replay Color The color of the gaze trail displayed in the replay Trail length The length of the gaze trail in milli seconds Replay rate The speed of the Gaze Replay as a percentage of normal speed Flip User Cam By flipping the UserCam picture horizontally by ha
8. are instead a number of import and export options available Using these tools a test leader can obtain full control of the raw data generated by the system Data types saved by the system Even though the information can not be accessed directly from the outside it may be useful to understand what data is saved by the system The following information is saved and managed by ClearView e Study information This contains the name of the study as well as study specific settings e Stimulus information All the stimulus information associated with each study including settings bitmaps movies etc e Subject information Information about each test subject including name subject information and a set of calibrations associated with the subject e Recording information Information for each recording for each subject and stimuli The recording information is separated into the following data classes e General recording information Contains time and date of each recording e Gaze recording Contains all gaze data provided by the eye tracker including time stamps gaze positions eye positions pupil size and validity codes For more information on the gaze data provided by the system see the chapter on Properties of the Tobii Eye Tracker e Event recording Contains all events generated and collected by the system This includes events generated by the stimulis presentation such as the precise time stamps for showing and hiding
9. hardware acceleration greatly reduces the processor load when doing the screen recording but may also cause smooth graphics and animations to become slightly jittery 26 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Screen resolution When using screen recordings as the Web stimulus does trade offs there is a trade off between screen resolution and resource requirements For standard screen recordings we recommend using a 16 bit color depth and a 1024x768 resolution on the computer settings and a 10 fps frame rate for the screen recording This will put a reasonably low load on the computer and the video files produced become fairly small about 2MB minute If more colors higher resolution or faster frame rates are used this will require more computational resources during recording and more storage space If accurate timing in the eye tracking is required we recommend using a double computer configuration in such cases see chapter on Setting up the Tobii hardware Screen stimulus The Screen stimulus is not really a stimulus but rather a type of recording This stimulus is used to record a video of what happens on the user s screen during gaze recording This may be used to achieve a good qualitative understanding of gaze behavior while using different types of software on a computer The Screen Stimulus may also be used in combination with the web recording tool described in f
10. in full screen during the course of the recording 37 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Important notes Use a double computer setup Reducing the resolution and frame rate on UserCam screen capture and video capture Showing the Live Viewer in a small window only Do not show the UserCam picture live Reduce CPU load LiveViewer The LiveViewer only shows every other image when running with for the slideshow stimulus In order to see all images insert an empty Slideshow image between every slide and have it show for just a fraction of a second Controlling ClearView from other applications ClearView has capabilities for presenting a large range of stimuli and collecting data from numerous different sources However in some cases other applications are used for data collection in parallel with ClearView e g EEG recorders logging applications or psychology testing applications For this purpose ClearView is fitted with a mechanism to receive control signals over the TCP IP interface The Tobii Software Development Kit Tobi SDN which is purchased separate from ClearView includes details on how to build an application which sends such signals to ClearView Several applications including E Prime from Psychology Software Tools INTERACT from Mangold and The Observer from Noldus have implemented the interface and can control ClearView How to set up ClearView to receiv
11. of your Windows operating system Configure dual monitor setup This step is only required if you will use your system with double monitors In order to use double screens your computer must be equipped with a dual head graphics card see chapter on System Requirements and you must have two monitors connected to the dual head graphics card Once the graphics card is installed with the card specific drivers right click on the desktop select Properties gt Settings gt Advanced If you are using the recommended ASUS graphics card click on the tab named Dual head Select the option to Recommended placement of the two screens extend the desktop onto the secondary display In on the extended desktop Windows XP right click on the desktop choose Properties and go to the Settings tab Click the representation of monitor 2 and check the box Extend my Windows desktop onto this monitor Configure your displays so that the standard operator monitor is set as the primary display and the monitor on your Tobit Eye Tracker is secondary display Position the displays relative to each other on the extended desktop It is recommended to position the secondary display corner to corner with the primary display see figure This minimizes the risk that the mouse pointer accidentally moves between the screens Once you have installed ClearView under global settings gt monitor configuration the monitor mode must be changed to Du
12. properly handled with ClearView No If the Javascript somehow affects the visual layout for example by presenting dynamic menues these are simply ignored by the recording tool Therefore you can still make good recotdings on pages with limited amount of Javascript effects No Flash animations are simply ignored by the web recording tool The web recording tool automatically disables the ability to change size of the browser window This is done to ensure that the bitmap that is saved of each web page is consistent throughout the entire recording session Clear View identifies web fames based on the URL the width and the height This means that frames with the same content but different URLs will be treated as different frames in analysis Also frames with the same URL but different sizes will also be treated as separate pages in analysis During web stimulus presentation ClearView tries to disable hardware graphics acceleration automatically This is necessary in order to capture a video of the screen effectively On some computers mostly certain laptop models hardware acceleration can not be disabled by ClearView In these cases it may be necessary to turn off the hardware acceleration manually To do this in Windows XP right click on the Desktop and choose Properties Go to the Settings tab and click Advanced in the next window use the slider on the Troubleshoot tab to turn the hardware acceleration to none Disabling
13. refresh rate there is thus a 15 ms uncertainty window For TFT monitors such as the one built into the Tobi ET 17 there is not a fixed refresh time but instead a fading in of each image which takes up to 25 ms to complete if going from black to white The timing characteristics of the Tobu eye tracking hardware itself are described in detail the chapter The Tobii Eye Tracker The time when each slide is presented is not always precisely the times specified in the definition of the slide show This is due to the fact that the command to the graphics board may be delayed based on computer load and the time slicing mechanisms of Windows The timestamp of showslide can differ up to 20 ms from the specified times in the slide show definition For highly accurate analysis we therefore recommend always looking carefully at the time stamps To ensure maximum precision in timing for subject responses we recommend using a game pad such as the Microsoft Sidewinder instead of relying on the standard computer keyboard The reason for this is that the standard keyboard usually has a delay of up to 20 ms whereas a game pad has considerably less delay Web stimulus The Web stimulus uses the contents of a web browser as stimuli The subject is presented with a standard Internet browser at a predefined start page and is free to browse the Internet in any way Web stimuli is typically used as a comprehensive tool for web usability and web ad
14. right eye by the system 1 The system has only recorded one eye and has made some assumptions and estimations regarding if the recorded eye is left or right However it is still highly probable that the estimations done are correct The validity code on the other eye is in this case always set to 3 2 The system has only recorded one eye and has no way of determining if this is the left or the right eye 3 The system is fairly confident that the actual gaze data is actually incorrect or corrupted The other eye will always have validity code 1 4 The actual gaze data is missing or definitely incorrect A couple of gaze data with validity code 4 on both eyes followed by a number of gaze data with validity code 0 on both eyes are usually a sure sign of a blink It is recommended that the validity codes are always used for data filtering to remove data points which are obviously in correct For most studies we recommend removing all data points with a validity code of 2 or higher 17 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Using the ClearView analysis software Introduction The ClearView analysis software is an application designed to provide easy to use yet flexible and powerful recording and analysis of eye tracking data The package facilitates efficient multi person and multi trial studies in the fields of experimental psychology commercial usability advertising low v
15. setups can be found For most applications double monitors are used For resource intensive applications like web studies external video or using the Live viewer a double computer setup is recommended Standard computer monitor Standard computer monitor Monitor cable Monitor cable Monitor cable USB cable and Firewire cable USB cable Monitor cable Firewire cable Crossover TCPIIP cable a AT Q Mf A q Combined eye tracker and application computer M Y Hill N Eye tracker Application computer computer Double computer double screen Single computer double screen configuration configuration USB cable Firewire cable Monitor cable Tobii 1750 MNN alll N USB cable and Firewire cable Monitor cable Combined eye Tobii tracker and 24 24 1750 application w zE computer S Crossover Yew gomputer iets Single computer single screen Double computer single screen configuration User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Setting up the Tobii 1750 Always power down your computer before connecting or disconnecting your Eye Tracker product Connect the Tobi 1750 your Tobit Eye Tracker server and application computer s Connect the four cables in the following order 1 Monitor connector 15 pins should be connected to graphics card of the application computer 2 U
16. to Internet Protocol TCP IP in the list of items used by the connection and click the Properties button click Use the following IP address and define a black address for that computer Firewalls will sometimes prevent ClearView from connecting to the eye tracker computer and the firewall needs to be instructed to allow the connection This is made by making an exception and opening up the port 4455 for TCP and port 4457 for UDP traffic on the eye tracker computer s firewall To do this for the built in firewall in Windows XP Service Pack 2 go into the Control Panel on the eye tracker computer an open the Windows Firewall On the Exceptions tab click Add Port fill in TET Server as name and 4455 as Port number choose TCP and click OK do the same for the name tTime and port 4457 for UDP traffic User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Single or double screen configuration The ClearView analysis software is designed to use single or double screens during testing Double screens are recommended as the standard configuration since it allows the test subject to be presented with only the stimulus while the test leader receives real time feedback of eye tracking quality during recording and set up Figure 1 Primary screen test leader display left and secondary screen eye tracker monitor right Different system setups Below schematics for four different system
17. useful as a tool to verify the quality of tracking and the quality of calibration for a certain test subject The tool displays an image as a background and the gaze point superimposed on this image In dual monitor mode the point of gaze is only displayed on the operator screen During real time gaze display a blue dot indicates that the system can track both eyes A red dot indicates that only the left eye is tracked and a green dot that only the right eye is tracked The real time gaze display tool is found under the Recording view After clicking on Real time gaze display select an image file to use as background during real time gaze display To quit real time gaze display press ESC to quit Pictures intended for testing the tracking accuracy can be found in the ClearView samples package in the folder Image Samples Accuracy test images Live Viewer The Live Viewer is a tool for monitoring an eye tracking session live It shows a live picture of what is being shown on the test subject s screen with the gaze point overlaid The Live Viewer can also take the picture from an external camera such as a web camera and show that live The UserCam picture is also saved to file and can be exported after a finished test along with a screen capture with gaze overlay All settings for the Live Viewer can be found in Global Settings under the Live Viewer tab and include what pictures to show and save to file and if the Live Viewer should be shown
18. users have tried to keep their head decently still but have not used a chin rest or a bite bar For each of the 64 points the average gaze data point was defined as the average of five gaze data points Accuracy was then defined as the average of the deviation between the 64 averaged gaze points and the intended gaze points over this test The average accuracy of the result from 10 different users was 0 5 degrees Drift effects The term drift indicates a deterioration of a calibration that occurs over time This is mainly due to changes in characteristics of the eyes that are caused by change of pupil size for example because of changes in surrounding light conditions or if the eyes become dry For the Tobi Eye Tracker drift over long time periods and great differences in light conditions range from 0 to 2 degrees for each eye individually However since the tracker allows binocular tracking it is possible to use a feature called binocular averaging Most drift effects are inversely symmetrical between the eyes and may therefore be averaged to remove a large portion of horizontal drift effects By doing so drift effects for most users are reduced to less than 0 5 degrees but may vary from individual to individual A few important things to keep in mind in order to minimize drift effects e Make sure to calibrate using a background color with the same light intensity as your intended stimuli e If re using an old calibr
19. 06 The validity and eye filter implemented in ClearView is based on the following algorithm Validity Filter Setting Normal Medium High Left Validity _ Right Validity _ 1 Validity Filter Eyes Found None Left Right Both Left Gaze Point Right Gaze Point ______ 2 Eye Filter Eye Filter Setting Leit RightAverage gt Gaze Point gt 3 Fixation Filter Figure 27 Chart describing how the validity and eye filters provide data to the fixation filter Fixation filter Fixation filters are used to group gaze data into meaningful fixations Many different algorithms for fixation definition have been proposed and are available among researchers and practitioners In part the purpose of the study influences which types of fixation filters are most suitable The fixation filter implemented into ClearView is based on the following algorithm Start a new potential fixation Take the next raw gaze point Run this gaze point through the validity and eye filter Did the validity and eye filter classify this as a valid filtered gaze point Is the filtered gaze point within X pixels from the previous potential fixation centre Add the filtered gaze point to the current potential fixation Reset the potential fixation centre to the last gaze point Are there further gaze p
20. Click a color box to change that color in the scale ot move the slider to change the transparency By changing the max value for the legend the Hot Spot uses as much as possible of the color range for the legend In order for different frames to be easily comparable the maximum values are the same for all Hot Spots By using fixation data for the Hot Spot calculations jitteryness and noise in the eye tracking data is filtered out before the Hot Spot mask is calculated This is suitable for studies with few recordings while raw data normally provides a more smeared out picture which is representative when there are many recordings and errors can be assumed to cancel 45 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Hot Spot Type AOI settings Color and Transparancy Time Segments Refence point There are four types of Hot Spot calculations 1 Fixation count Adds up all the fixations from all the recordings or gaze points for raw data 2 Fixation length Absolute Total fixated leneth on each spot of the image 3 Fixation length Relative The sum of the individual fixation lengths relative to the total fixation time on the image for each recording If in recording A the subject looked on the image for 10 seconds and on a specific object for 3 seconds In recording B the subject looked at the image for 10 minutes and on the specific object for 3 minutes
21. In this kind of hotspot the data from recording A and recording B will have the same weight 4 Subject percentage This hotspot shows how many percents of the subjects saw an atea of the image AOIs can be drawn on top of the Gaze Plot The color and transparency of the AOIs and their names can be changed This defines which points in time of different recordings start end or both should be treated as one When choosing Szart as reference point there will be only one green start marker on the Hot Spot time line and the blue time segments will zc ude all data from a certain time after Szart to another time after Szart If End is selected data from a time segment relative the End of recordings is included in calculations By choosing Bosh data from the first x seconds and from the last y seconds is excluded from the calculations For instance Exlude data from the first 1000 ms and the last 1000 ms this will exclude data from the first and last second of each recording in the analysis 46 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 E All will include all visits to the page in the Visits l analysis First only includes only the first visit of a frame in the analysis even if it was visited several times during a recording Scene tool Moving stimuli do not consist of separate images which can be made into Gaze Plots and Hot Spots like slideshows and web session
22. Load Subject button If they are a new subject use the New Subject button For detailed information on each stimulus type how to set it up and what is recorded see the chapter The different stimuli types below 19 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Record When the stimuli and subjects have been prepared recordings can be made In most cases a recording procedure will consist of four steps e Verifying tracking ability and the subject s position in front of the screen using the track status meter e Performing or selecting a calibration e Verifying calibration quality using the real time gaze display e Performing the stimulus presentation and doing the actual recording To access the recording tools click on the Record button on the toolbar or in the lower right corner of the ClearView main window For mote details see the chapter Recording Tools below Analyze Once recording is finished the data collected can be analyzed in the analysis section of ClearView There are several different tools available in ClearView for data visualization and analysis Depending on the type of study the work flow during analysis may vary quite a bit For many studies though the following steps would be performed e Using the different visualization tools gaze replay gaze plot and hotspot plot to get a qualitative view of the data and identify behavior of interest e Defin
23. SB connector should be connected to the USB port of the eye tracker computer 3 Firewire connector should be connected to any Firewire port on the eye tracker computer 4 Power connector should be connected to the supplied 12V Powerbox power supply which should in turn be connect to a normal power socket either 110 or 240V AC Make sure to connect the eye tracker to the same power socket as the computer which runs the TET Server Connecting the eye tracker and computer to separate power sockets may result in permanent damage to the eye tracker Turn on the computer last Figure 2 On the backside of the Tobii 1750 four cables are connected from left to right power USB Firewire and monitor cables Setting up the Tobii x50 Always power down your computer before connecting or disconnecting your Eye Tracker product Connect the Tobit x50 and your PC Connect the three cables in the following order 1 USB connector should be connected to the USB port of the eye tracker computer 2 Firewire connector should be connected to any Firewire port on the eye tracker computer 3 Power connector should be connected to the supplied 12V Powerbox power supply which should in turn be connect to a normal power socket either 110 or 240V AC Make sure to connect the eye tracker to the same power socket as the computer which runs the TET Server Connecting the eye tracker and computer to separate power sockets may result in permane
24. Tobii Technology AB 2006 TCPData 6 E A text string sent over TCP IP TCPKeyPress 7 ShowAVI 8 AVI movie file AOI data AOI This exports one data row per fixation The validity filter eye filter and fixation filter settings are first used to filter the data Thereafter the data is compared to the AOIs defined for the study The following columns are created Data column Description Time The timestamp in ms indicating start of the fixation Duration The duration in ms of the fixation AOI ID The unique identifier for the AOI that this fixation was in AOI Name The name of the AOI that this fixation was in Two special AOI idenfiers and AOI names exist e Blank ID 0 This denotes a fixation on a blank slide in a slideshow e Content ID 0 This denotes a fixation on the screen but outside any of the defined AOIs AOI List AOIL This export contains a list of all AOIs defined for the stimulus and the categories they belong to Combined data CMD This exports nearly all data from the system in one combined data file The purpose of this is to make parsing of the data easier for certain types of analysis tools The combined export contains all the information from the gaze data export the event data export the fixation export the moving bitmap export and the AOI export with the following changes e Change in validity code If the data in a certain row is an event instead of a gaze data the validity co
25. acker Server host Paths ClearViewData folder Database import export folder Stimuli folder 59 The source to use as UserCam picture normally a camera connected to the ClearView computer Specifies the input on the video source to use as UserCam picture Most cameras have only one input and this choice will have no options The codec to compress the UserCam picture with Microsoft Video 1 works reasonably well These are the settings of the currently installed camera and typically includes settings for brightness contrast etc These are also hardware specific settings which typically include size and frame rate for the video captured The source to use as Audio input for recordings normally the microphone port on the computer ot the microphone on a camera If using a two computer setup this must be indicated by checking the Remote computer radio button and specifying the IP address to the computer hosting the TET Server The folder containing the ClearView data base The default folder where ClearView saves exported studies subjects and stimuli or looks for studies subjects and stimuli to impott The default folder where ClearView looks for files to create stimuli from This is a good place to save the ClearView samples package and This is also the folder in which the attention grabbing AVIs 1 9 avi for the infant calibration should be placed User Manual Tobii Eye Tracker and ClearVi
26. al head Verify Internet explorer version Your default Internet browser should be Internet Explorer version 6 0 or higher User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Getting started Start the ClearView software Make sure that the Tobi tracker and ClearView software are properly installed and then start the application by double clicking on the ClearView icon Prepare your first study Enter a name of your new study in the Start ClearView study window that appears at program startup Click OK Select New from the left hand Stimuli area of the Prepare dialog box Select the Image icon and write a name in the Save Stimulus as text box Click Next A Stimuli Wizard Image dialog box will open Click the Browse button Find an image file you wish to show and double click on the file name The image can be in BMP JPG or GIF formats Select the option Until Keypress Click on the OK button Select New from the right hand Subjects window Type your name in the Subject s name text box Click OK Make your first calibration Ensure that you are sitting comfortably in front of the Tobit at a distance of approximately 60 cm Adjust your chair so that you can see the tip of your nose in the circular filter at the bottom of the eye tracker Select Record from the left hand toolbar Select your name from the central Subject area Click on the Calibrate button The Track status meter appears incl
27. apture cards have the option of capturing at least S Video and Composite e Video Input Device This will define the input device of your video capture card Usually there will only be one choice available which refers to the Video capture card installed on your machine e Video Compressor This defines the compressor to use to create the video recording The choice of compressor will impact the video quality the video file size the CPU load during recording portability etc For most purposes the Microsoft Video 1 compressor is recommended e Camera Settings These are the settings of the currently installed camera and typically includes settings for brightness contrast etc e Video Settings These are also hardware specific settings which typically include size and frame rate for the video captured e Use video as stimulus When this option is checked ClearView will display the video input on the subject screen during recording Once the settings above have been defined the above settings a preview of the video capture quality will be shown by clicking the Start Preview button This will display the video from your video source Note that in some cases the quality of the preview will be lower than that of the video captured to file 31 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Data recorded During recording Clearview will record a complete video of the input from the video ca
28. are available AVI Screen Web Moving bitmap Video capture and Scene camera stimuli as well as Live Viewer functionality require additional licenses 18 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Basic workflow When doing studies with ClearView the basic workflow is divided into three main areas Prepare Record and Analyze Ei eari se ea 8 Pe Shady Seting Dye Tracker Mele Paes oseos vad E Prepare Akl erra or kegid Hirek one piecka be be urad in Huir Carpet TET Sarete diu bat LAPON F Figure 8 The ClearView main view Of these three general groups of actions the only time a Tobii Eye Tracker is required for the Record actions where actual eye tracking data is being collected You are free to Prepare or Analyze studies in your office or at home and thus leave your Tobii free in your lab for others to run studies Prepare During the prepare phase two main actions are completed e Creating stimuli e Selecting and or creating test subjects To start preparation click on the Prepare button on the toolbar or in the lower right hand corner of the ClearView main window Create a new stimulus by clicking on New stimulus and select the type of stimuli you wish to use For each type of stimulus a separate stimulus preparation wizard appears To select test subjects use the right hand window If these subjects have been used in previous studies then click the
29. ate with transition matrix less than 200 AOIs defined URL length max 255 URLs longer than 255 characters will be truncated and characters only the first 255 characters will be used in the AOI template Using the Empty template The Empty Excel template emptytemplate x s is the simplest template available After exporting data from ClearView to the Empty Excel Template there will be six sheets of data in Excel These include the five data sheets GazeData EventData AOIList FixationData and AOIData with data identical to what is exported by the text export from ClearView See the chapter on Text export above The last sheet StudyData includes information about what stimuli subjects and recordings are included in the data Data from the different recordings are placed after each other left to right on the sheets with an empty column at the beginning Since Excel only accepts 256 columns and the GazeData section includes 16 columns per recording the maximum number of recordings that can be exported to the empty template is 15 Creating your own Excel templates To create your own template create an Excel document with empty sheets with any of the following names GazeData EventData AOIList StudyData FixationData AOIData If the particular sheet exists in the Excel template ClearView will automatically detect it and save the relevant data into the sheet No column headers have to be created for the sheets as these are automatically ge
30. ation verify calibration quality before the test session and if this is not very good perform a new calibration e Use binocular averaging as this removes a large portion of the drift effects e Do not change light conditions too much during a study Head movement compensation The term head motion compensation error is the additional error that can occur if the subject moves or turns the head For the Tobit Eye Tracker head motion compensation is close to perfect with an error that is less than 1 degree across the entire field of view of the camera This includes not only head translations sideways and up or down but also movement back and forth as well as large head rotations 15 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Tracking ability General tracking ability Tracking ability is the eye tracker s capability to track as large a of the population as possible The Tobi Eye Tracker provides good tracking ability and handles well also with varying light conditions and people wearing glasses or contact lenses The Tobu 1750 system performs very well across all ethnic groups and age groups The Tobu ET 17 system has some difficulties tracking certain individuals for instance people with dark brown eyes It is easy to verify tracking ability of a particular subject by using the track status meter see description in the ClearView section of this manual In order t
31. aved image also includes statistical information to identify the data behinds the image Believe it or not but this exits the Gaze Plot tool Displays the Gaze Plot in full screen Hit any key or click the mouse to return to the Gaze Plot tool By choosing this option or pressing Ctrl C the Gaze Plot image is copied to the Windows Clipboard and is available for pasting in other programs like Word or Powerpoint The copied image also includes statistical information to identify the data behinds the image The color and the transparency of the gaze trail can be altered to be clearly visible against the background image By checking this box the numbers in the fixation circles will always start from one in an image even if the time segment plotted changes If this box is left unchecked all circles will have the number of the fixation counted from the start of the recording This is also the number which is shown in the fixation info when the mouse cursor is moved over a fixation circle AOIs can be drawn on top of the Gaze Plot The color and transparency of the AOIs and their names can be changed 43 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Hot Spot plot The Hot Spot plot is a powerful way to visualize the gaze behavior of an entire eroup of recordings To use this select the recordings you want to include in the plot and thereafter click on the hotspot plot button
32. base Edit Clearview Database Choose item to edit Study eo Export and import for subjects is not implemented Export Import Delete Export Study Choose studies to export from Clearview C Drifttest 5 MB C Kirks test 32 MB C moppestudie 5MB O test 2 KB C web test 163 MB Export studies to folder CAT emp Browse Export J Exit Figure 29 The ClearView data base editor To import an exported study into ClearView select the Study button and the Import tab Use the browse button toe choose the folder containing the expst folder 1 e no the expst folder itself select the studies to import and click the Import button To delete studies or subjects use the Delete tab in the database view choose the subjects or studies to delete and click the Delete button 66 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2005 Literature References Stanford Poynter Project http www poynterextra org eyetrack2004 index htm http www poynterextra org et i btm Eye Tracking Methodology Theory and Practice Duchowski A T 2003 Springer Verlag London UK ISBN 1 85233 666 8 67
33. ce from the camera to the eye in mm measured from surface of eye to centre of the filter in front of the camera Pupil left eye Code left eye Screen X right eye Screen Y right eye The size of the pupil in mm The validity of the gaze data please refer to chapter on Tracking Ability for interpretation of this The horizontal position of the gaze point on a normalized scale 0 is left side of screen 1 1s right side of screen The vertical position of the gaze point 0 is top 1 is bottom 12 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Cam X right eye The horizontal location of the pupil in the camera image 0 is left edge 1 is right edge Cam Y right eye The vertical location of the pupil in the camera image 0 is top 1 is bottom Distance right eye The distance from the camera to the eye in mm measured from surface of eye to centre of the filter in front of the camera Pupil right eye The size of the pupil in mm Code right eye The validity of the gaze data please refer to chapter on Tracking Ability for interpretation of this The distance and pupil size measures are calculated to be as close to real values as possible However individual differences in the eyes of subjects and the strength of glasses contact lenses will cause errors in these values However the measures still reflects changes in head position and pupil size accurately
34. connect through USB Note As the eye tracking software and ClearView develops these requirements may change without notice Please contact Tobii for up to date recommendations Setting up the Tobii hardware The Tobu Eye Tracker unit may be operated in the same light conditions where one would normally use a conventional computer display As the eye tracking mechanisms are somewhat sensitive to near infrared NIR light we recommend avoiding potentially disturbing sources high levels of NIR light Such sources include direct sunlight or extreme levels of in direct sunlight could cause problems while ordinary office light conditions with limited amount of sun light are not a problem User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Single or double computer configuration The Tobu Eye Tracker is designed to work well in both a single computer and a double computer configuration If the studies involve resource intensive applications in parallel with the eye tracker we recommend using a double computer configuration Examples of such applications are when using high frame rate video capturing when conducting web studies or very high demands on timing accuracy Use of the ClearView Live Viewer is also very resource demanding and double computer setups are advisable In double computer configuration one computer is dedicated to running the eye tracking software the eye tracking compute
35. considered equal URL Pages with identical URLs are considered equal disregarding their actual content URL and Size Pages with identical URLs and sizes are considered equal disregarding their actual content Page content Pages with identical graphical content are considered equal disregarding their URLs Data filters ClearView always records and stores unfiltered data However in the analysis steps you have the option to use different types of filters to perform data abstraction or to remove bad data Settings for the data filters are available under the Settings gt Study Settings menu option The settings made here are applied both to the different gaze visualization tools such as the gaze replay and the gaze plot as well as to the data export features available 62 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The basic filters in ClearView are the validity filter the eye filter and the fixation filter Validity and eye filter The validity and eye filter is used to combine or sort binocular data as well as to filter out bad data The validity filter is primarily used to remove bad data For each gaze data that is recorded a certain validity code is assigned to right and left eye respectively Basically this is a good indication of how certain the system is that it has recorded the correct data See the chapter on Tracking Ability for more informa
36. d be placed in the ClearView Stimuli folder and be named 1 avi 2 avi 9 avi With ClearView default movies suitable for infant calibration are provided A bouncing ball to be used for calibration and a number of small attention grabbing AVIs can be found in the Clear View Samples package compliments of Scott Johnson at NYU In some very specialized applications it might be of use to calibrate part of the screen only In the advanced settings the region of the screen to calibrate can be changed User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Analysis filter Settings for post recording processing of the eye tracking data see also the section Data filters below Validity filter Higher validity filter exclude data which is not perfect Eye filter Specifies which eye s to use data from Fixation filter Defines the maximum distance between two points for them to be considered belonging to the same fixation and the minimum time for which gaze needs to be within the radius to be considered a fixation Analysis Replay Trail Specifies if a trail should be displayed behind the fixation dot in Gaze Replay and how long this trail should be in milliseconds Color To change the color of the fixation dot and trail click the colored square and choose a new color Web Group web pages based on Defines what ClearView looks after to determine whether two visited web pages are to be
37. d one or more red markers indicate the end of the different recordings By dragging the ends of the blue bar the time segment to include in the Hot Spot can be changed Note that by making the time segment smaller some recordings might be excluded from the calculations all together 44 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Hot Spot settings Most settings and controls in the Hot Spot can be accessed by right clicking the HotSpot image These same settings can also be found under the different menus in the Hot Spot tool File Menu Save image Exit View Menu Full screen Edit Menu Copy image Settings menu Legend Settings Colors and Transparency Legend Scale Data Settings Raw Fixation Data Saves the Hot Spot image to file The saved image also includes statistical information to identify the data behinds the image Believe it or not but this exits the Hot Spot tool Displays the Gaze Plot in full screen Hit any key or click the mouse to return to the Gaze Plot tool By choosing this option or pressing Ctrl C the Gaze Plot image is copied to the Windows Clipboard and is available for pasting in other programs like Word or Powerpoint The copied image also includes statistical information to identify the data behinds the image The colors and the transparency of the Hot Spot mask can be altered to be clearly visible against the background image
38. des for both eyes are set to 5 This is done to facilitate easy parsing of the data file e Fixation number The fixation number is given in the column fixation If the particular gaze data does not belong to a fixation the value is set to blank AVI export AVI export is used to create an AVI movie of the gaze replay see above chapter Any rendering codecs installed on the computer can be used For screen capture data the Techsmith Screen Capture Codec TSCC is recommended To view a movie made in TSCC this codec needs to be installed on the computer where the movie is played as well TSCC can be downloaded free from www techsmith com Other common codecs include MS Video 1 However this codec does not support AVI export in higher resolutions 51 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Merging stimuli from separate studies If data collected with different copies of ClearView but based on the same stimulus is to be analyzed together individual recordings can be exported from the respective stimulus and into a stimulus of the same type but without any other recordings To export or import recordings open the study to export from import to go to File menu Export Import and choose Recordings On the Export tab the stimulus and recordings to export can be chosen On the Import tab the location to import data from is defined available recordings defined and the stimulus to impor
39. e calibration routine displays a series of calibration points on the screen During calibration the subject should concentrate on focusing the eyes on these points The subject does not have to keep the head 35 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 still during calibration in fact relaxed movement tends to improve calibration quality The Tobu tracker has unique long lasting calibrations as described in the chapter Properties of the Tobii Eye Tracker This allows individual calibrations to be re used for later test sessions However for maximum accuracy it is recommended to verify calibration quality using the real time gaze display and if required perform a new calibration before each separate test session There are several options to customize the calibration routines to suit a particular subject or study These options can be found under Study settings and include number size speed and color of calibration points Also there are two special calibration routines intended for subjects with poor eye site or short attention spans called ow vision calibration and infant calibration Low vision calibration The low vision calibration is a operator paced calibration procedure with special graphics during the calibration procedure The number of calibration points and their locations are the same for the low vision calibration as for normal calibration but instead of a pu
40. e top left pixel of the bitmap is used as transparent color e Start x Start y Stop x and Stop y coordinates four columns Defines the picture s start and stop positions on the screen measured in pixels from the top left corner of the screen x left to right y top down The coordinates define the centre position of the bitmap e View time The view time or period for the particular action e Type of movement The type of movement that should take place This can be any of the following types e Static The picture is simply shown at the start coordinate for the view time defined e Linear The picture moves with a linear motion from start to stop position in the view time defined e Sinus The picture moves in a sinusoidal motion from start to stop position in the view time defined e Jump The picture jumps in a single step from start to stop position and then stays there for the view time defined e Number of repetitions The number of times that the particular motion takes place E g having two repetitions for a static movement simply doubles the view time while for linear sinusoidal and jump movements it makes the picture move jump from the start position to the stop position and back again 28 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 e Label A text label for each action in the script This can later be found in exported data files for reference To crea
41. e trigger signals The ClearView trigger mechanism is a way of passing information and control sionals to ClearView from outside applications When using trigger signals ClearView listens for communication over TCP IP Ethernet connection on port 4456 which needs to be open for communication through any firewalls or similar To open this port find the settings for the firewall on the ClearView computer and specify that port 4456 is safe for TCP communication There are different types of signals that can be sent by an external application Function call Description Initialize Connect to ClearView and performs internal initializations Initialization needs to be performed before the start of a recording can be triggered Close Disconnect from ClearView and perform internal cleanups Start Start a recording This function call replaces the pressing of the button Start in ClearView StartWithName Start a named recording By using this method the name of the recording is specified when it starts Stop Stop an ongoing recording LogEvent Add a text data record to an ongoing 38 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 recording The text data entered shows up time stamped in the ClearView Event log file SendGenericEvent Sends a generic event which forwards an image or AVI slideshow to the next image movie the same way a key stroke would do on the ClearView computer
42. ection Recording tools below 20 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 e Infant Calibration AVIs A set of AVIs that have been developed by Scott Johnson at New York University for calibration of infants Place these AVIs directly in the Clear View Stimuli folder Read mote about calibrating infants in the section Study Settings below e Moving bitmap examples Examples of scripts for Moving Bitmap stimuli e Slideshow examples Examples of scripts for creating Sideshow stimuli The different stimuli types When first opening a study in ClearView the Prepare view is presented This view contains all necessary tools to prepare a study including what stimuli to show and what subjects to show them to E Prepare dinem o bad kima and subjects bo be used in study Y b Figure 9 The prepare view includes controls for creating eye tracking tests In the left part of the Prepare view a list of all studies in the study is shown These can be viewed by clicking Preview button to see how they will be presented to subjects they can be edited by clicking the Edit button as long as no recordings have been made on them and they can be deleted from the study by clicking the Delete button To create a new Stimulus click the New Stimulus button which will bring out the Stimulus wizard where the stimulus type and name is selected The different stimuli types are discussed be
43. ed on a client server model where one or several applications act as clients and the eye tracker engine as server See the below image for an overview of the system TCP IP Serial USB cable Firewire cable P Monitor cable Tobii eye Tobii eye Application tracker server tracker software eg Tobi library ClearView eye tracking a hardware The software can be placed on a single or on two separate machines Figure 5 Overview of the Tobii system 10 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The Tobii eye tracking hardware Different hardware platforms are available from Tobu including the Tobu 1750 the Tobi x50 and the Tobi ET 17 The different hardware versions consist of similar components TFT Display not in the x50 The TFT display is based on a high quality TFT display unit The display has excellent contrast and brightness and provides a maximum resolution of 1280x1024 pixels It also provides very fast response time of 25 ms which allows for good image quality with low smearing for moving images For studies that place high requirements on the smoothness of moving images on the screen we recommend the Tobii x50 together with a standard CRT monitor Camera A high resolution camera with a large field of view is used to capture images of the subject s eyes NIR LEDs Near infra red light emitting diodes NIR LEDs are used to generate even
44. ed together Combine consecutive fixations treat fixations occurring right after each other all within the same AOI as one Information to show in charts Median Data I Handle AOb based on nare m Combine cons e cutie e fis ations Figure 25 Special options in the AOI template main view 54 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Limitations in the AOI template There are limits in the amount of data analyzable in the AOI template These limitations are due to limitation in data size in Excel or are imposed to ensure that calculations do not take excessively long times 20 minutes of gaze data If gaze data is exported the maximum length of a recording is roughly 20 minutes corresponding to the Excel maximum of 65000 rows 150 minutes of fixation If fixation data with an average of 7 fixations per data second is exported the maximum recording length is roughly 150 minutes corresponding to the Excel maximum of 65000 rows 40 recordings A maximum of 40 recordings can be exported to the AOI template 1500 AOIs A maximum of 1500 areas of interest can be defined in the data exported to can be exported to the AOI template 2000 slides URLs A maximum of 2000 URLs or slides can be included in the data exported to the AOI template 40 recordings A maximum of 40 recordings can be exported to the AOI template 200 AOIs in the A transition matrix is only possible to calcul
45. es precision animated movie files from motions the scripts to provide smooth animations However jitteryness still occurs if the stimuli presentation process in the computer does not get enough time slots to generate smooth graphics motion This can be the case if the TET Server itself is running on the same machine as ClearView which does the stimuli presentation Therefore when smoothly animated moving bitmap stimuli shall be used we strongly recommend a two computer configuration see chapter on Setting up the Tobii hardware Screen Since CPU load needs to be minimized in moving bitmap stimuli resolution the stimulus AVI is rendered in 600x800 and will be displayed in this resolution regardless of screen resolution 29 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 AVI stimulus The AVI stimulus can show one or a sequence of AVIs as stimulus This is useful for a variety of studies ranging from psychology studies and infant studies to advertising studies Preparing the AVI stimuli The following parameters can be edited for the stimulus e Background color Sets the color used for the background if your AVI movie is smaller than the entire screen e AVI path Sets the AVI file to play be used as your stimuli e Show AVI until Defines what event will stop the playing of one AVI and progress to the next in the list The alternatives are to play the AVI until it is finished to l
46. ew analysis software Tobii Technology AB 2006 License Key Existing License Keys New License Key Study settings Calibration No of calibration points 2 5 9 or 16 Type of calibration Normal Infant ot Low vision 60 A list of all ClearView license keys installed on the computer Each key shows if it is valid for the current eye tracker its expiry date and which Add Ons it is valid for New license keys are entered in this field and added to the list of keys available for recording The default calibration routine is set to five points which takes roughly 10 seconds and is recommended for most studies If shorter of calibration is required two point calibrations can be made with a trade off on tracking accuracy Using nine or sixteen calibration points will increase accuracy some but not extensively Three different calibration routines are available as follows Normal This calibration is recommended for most subjects A pulsating dot is displayed at each calibration point The calibration is automatically forwarded between points Infant This calibration is recommended for infants and other subjects with attention difficulties Instead of a dot AVI movies are displayed for each calibration point The following AVI movies are used by the infant calibration procedure Low vision This calibration 1s recommended for subjects with poor vision who have difficulties seeing the standard ca
47. for smooth pursuit studies preferential looking paradigms reaction type studies and more The stimulus wizard imports one or mote scripts and renders an AVI based on these For each moving bitmap stimuli the following parameters are editable e Background color Defines the color of the background screen e Background image Allows you to define an image to use as background for the stimuli e Quality The frame rate of the AVI rendered by ClearView Low 20 fps Medium 35 fps or High 50 fps Preparing the moving bitmap stimuli To import a Moving Bitmap script click the Add script button in the Moving bitmap Stimuli wizard window and click Import to find your particular script file The scripts are imported from tab delimited text files according to a specific format A Microsoft Excel template provided in the ClearView sample package can be used to create such script files To do this create a new Excel document using the Moving Bitmap Generator template provided in the ClearView Sample pack enter yout script information and save as a text file Each row in the script contains a particular action The actions are carried out in sequence The script file must be a tab delimited text file where each row except the header row in the text file contains the following information from left to right e Bitmap file Defines the picture to use for this particular action in the script Any BMP JPG or GIF file will work The color of th
48. gure 6 The TET Server icon on the System Tray includes those few settings the TET Server needs As opposed to most other remote eye trackers on the market the Tobii Eye Tracker uses binocular eye tracking For each gaze data item data is collected simultaneously for both eye There are several advantages to this binocular tracking can yield higher accuracy through binocular averaging less drift better robustness through redundancy of data and also provides a value in itself e g to measure vergence in vision studies Gaze data is sent in real time to the application where it may be used in any way appropriate saved to file for later analysis or used in real time with a gaze contingent or eye interaction applications The following data is provided to the application by the eye tracker through the TET Server Data column Description Time The timestamp in microseconds for when the gaze data was recorded The time is based on the high resolution Tobii timer Screen X left eye The horizontal position of the gaze point on a normalized scale 0 is left side of screen 1 is right side of screen Screen Y left eye The vertical position of the gaze point 0 is top 1 is bottom Cam X left eye The horizontal location of the pupil in the camera image 0 is left edge 1 is right edge Cam Y left eye The vertical location of the pupil in the camera image 0 is top 1 is bottom Distance left eye The distan
49. he camera image Top head motion speed is approximately 10 cm s which is enough for most head movements taking place while looking at objects on a computer screen especially since recovery time from total loss of tracking to full tracking quality is 100 ms once the subject stops moving Gaze angles A measure related to freedom of head movement is the extent to which the system allows for large gaze angles i e that the user looks far away from the camera which is placed just below the display The Tobii Eye Tracker allows for gaze angles up to 40 degrees in the semi circle above the camera measured from the camera mounted below the screen Below the camera the allowed gaze angles are up to 10 degrees Tobii monitor 7 Z 7 4 The eye tracker provides good accuracy throughout the entire range of tolerated Max gaze angle Le 40 degrees on semi circle above camera gaze angles SS i ld 10 degrees directly below camera The meaning of validity codes The TET Server provides validity codes for each eye with every gaze data point The validity code is a measure of the systems certainty that it has recorded the correct data The validity code ranges from 0 to 4 with the following interpretations for each value Q The system is certain that it has recorded all relevant data for the particular eye and that the data recorded belongs to the particular eye no risk of confusing left eye with
50. he subject is not looking properly at the screen anyways However if timing is absolutely critical it is recommended to compare the timestamp of the recorded data to verify a constant frame rate Since other applications running on the eye tracking computer may cause highly varying frame rates for older eye trackers a double computer configuration is recommended for time critical studies in particular if these are combined with other recoutce demanding software 13 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Latency Latency is defined as the time taken from when the actual eye position is recorded until data reaches the application Thus the latency of gaze data is the sum of the time taken for camera exposure transfer calculation and delays in the system For post analysis applications such as slide show studies and more the measure of latency is irrelevant However for real time applications such as gaze contingent applications and eye based interaction latency can play an important role For the Tobu 1750 typical latency is between 25 and 35 ms when used in normal conditions and limited head motion on a 2 4 Ghz Pentium 4 PC For the Tobi ET 17 typical latency is between 30 and 50 ms As described in the Frame rates section the frame rate may drop under certain conditions for example during rapid head motion Under such conditions latency also increases up to a worst case
51. i with subjects created added in the Prepare view Ed arvin 252 Fie Shady nye Dye Trokar Hag FED DO an0a A ameer lia Record Sekvi glide pubject ond calibration bo be ued in regie Stima 5 cc Cab aton A Cipi TET Saree cru beet LETO a Figure 14 The ClearView recording view 34 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The Recording view contains a list of stimuli prepared a list of subjects added to the study a calibration area and function buttons for calibration and recording To start a recording simply choose a subject and calibrate if no accurate calibration already is available choose a stimulus and click the Record button Track status meter The track status meter is shown before each calibration real time gaze display and recording It can also be activated directly by clicking the track status icon in the ClearView toolbar In double monitor mode the track status meter can be shown on both the subject screen and the operator panel See also the chapter Global Settings The purpose of the track status meter is to verify that the test subject is in the correct position in front of the eye tracker and that system is able to robustly track the subject The track status meter shows a black box with two white circles and a text bar at the bottom The black box represents the field of view of the eye tracking camera and the white dots represents
52. ight eye Cam Y right eye Distance right eye Pupil right eye Code right eye Fixation data FXD The horizontal position of the gaze point measured in pixels from the left The vertical position of the gaze point measured in pixels from the top The horizontal location of the pupil in the camera image on a scale from 0 to 1 The vertical location of the pupil in the camera image on a scale from 0 to 1 The distance from the camera to the right eye in mm The size of the pupil in mm The validity of the gaze data This exports one data row per fixation The validity filter eye filter and fixation filter settings are used to filter the data Gaze data that do not belong to any fixation are omitted The following columns are created Data column Number Time Duration Screen X Screen Y Description A sequential serial number given to the gaze point The timestamp in ms for start of this fixation from the start of the recording The duration in ms of the fixation The horizontal position of the fixation centre measured in pixels from the left The vertical position of the fixation centre measured in pixels from the top 49 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Event data EVD This exports the event data for each recording The following columns are created Data column Time Event Event key Data 1 Data2 Description
53. immediately to the right of the Browse button or next to the Blank slide button e View time Sets the time the image will be displayed This is disabled when Until key press is selected e Until key press Displays the image until the subject presses a key This is disabled when View time is selected When the configuration of the slide is finished click the Add button to add the slide to the slideshow You can Edit Remove or change the Slide position using the arrow buttons and the buttons below the list of slides in slideshow window To import an entire slide show from text file click the Import button use the browse button to find a slide show script e g one of the example scripts in the Sample package Using scripts to simplifies creation of large slide shows for example with pre randomized slide orders The import file must contain tab delimited text where each row contains columns with the following information in the following order e Image file name eg C femp imagel jpg If the file name is blank or the file cannot be found it is set to be a blank slide Using the word b ank as image file name also sets the slide to blank e Color of background eg red or 110 55 255 The color may even be set using standard Windows names for colors or using the RGB color code with a comma as delimiter e Time Keyptess eg 0 34 The unit is seconds If the time field is blank or has the text Rey press the slide will advance on a
54. imulus presented in the physical world This can for example be a collection of objects that are moved around on a table For proper gaze recording the stimuli should to the greatest extent possible be positioned in a 2 dimensional plane Any deviations from the plane for example caused by the height of objects placed in the plane will cause parallax errors in the gaze estimation e A calibration grid which is placed on the surface that is being tracked is used for individual calibrations and to align the point of view calibration e A scene camera which is used to generate a video of the scene presented to the test subject The camera needs to be connected to a functioning video source on the computer where ClearView is running Please refer to the System Requirements chapter for information on recommended video capture cards e A Tobi x50 eye tracker e One or two computers with TET Server and ClearView software 32 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Preparing the external video capture In the prepare view for Scene Camera there are a number of settings describing video source and intended capture results These settings are identical to those used for External Video Capture Please refer to the chapter on External Video Capture for a description of these settings EaScene Camera Wizard Scene board x LA Scene Camera Define Scene Camera Stimulus Video Set
55. in the Analyze view Tise Segment Inchde data from O ma to 40600 ms A SA E SSeS e Figure 21 The Hot Spot shows areas of interest as brightly The Hot Spot plot consists of the stimuli as background image and a hotspot mask superimposed on top of this The Hot Spot mask consists of a black background with high lighted areas where test persons have been looking Merging images into one Hot Spot The left pane of the Hot Spot tool includes a list of all images shown during recording In some cases there is a need for merging the data from several images into one Hot Spot e g if a web page has some dynamic content or unique session URLs By creating Hot Spot groups and dragging frames which are to be merges into the same group such Hot Spots can be created For these Hot Spots the Hot Spot mask consists of data from all images in the group while the background image can be chosen among the members of the group In the image above one group has been defined containing two images the first of which is currently shown as the background of the Hot Spot Time segmenting hotspots In some cases it is if interest to create a Hot Spot based on only a smaller time segment than the image was shown during recording At the bottom of the Hot Spot window a time scale shows a representation of the different recordings and the time segment chosen for the Hot Spot One or more green markers indicate the starting point of the different recordings an
56. ing areas of interest to facilitate meaningful data quantification e Making raw text exports or use DirectExcel templates for quantitative analysis and conclusions To access the analysis tools click on the Analyze button on the toolbar or in the lower right corner of the ClearView main window For more details see the chapter on Analysis and export tools below The ClearView Sample package On the ClearView installation CD there is a folder with Sample files including a Sample package These folders contain a number of useful files including pictures movies analysis tools and templates for easy creation of different stimuli Place the Sample package in the ClearView Stimuli folder defined in Global Settings The default location of this folder is C Program Files Tobii ClearView Stimuli The Sample package includes the following folders e AVI Samples AVI movies that can be used to test the AVI stimuli e Direct Excel Templates Analysis templates used with the Direct Excel export from ClearView See also the section DirectExcel export in this manual e Generators Excel templates that can be used to create script files for Moving Bitmap and Slide show stimuli e Image Samples A collection of pictures in different formats that can be used to test the Image and Slide show stimuli In this folder there are also specially designed accuracy test images to test calibration quality with the Real time gaze view tool See the s
57. ings bo inpia 5 x Columns tr i barren let I dehe 1 LELI Hiir rs A r pidt bip td Fet l TT A a birar betas 3 a nd a e Tri fr Tc i a we a bsb orr J a Mancs bo ealeuiala Soca ele e a 1 10 y 4i t 1z n 1 15bit CE E ae pr Shoe cht i E a E OL zl haves transition matrik Secu a repeat a Update te ere ai et iil a x Liri bra Ririntile p diia af Beier Troner A AG kt i BGlfiebs Jf Drena f jal lf 4 aphan h a O a wl a Che a en E Figure 23 The main view in the AOI template The main view of the AOI template includes three lists which are used to select the data to base statistical analysis on The first list shows the slides web pages shown ot visited by during the recordings in the second list In the third column a list of the defined AOIs can be found To select what AOIs to analyze choose the appropriate slides web pages recordings and AOIs by clicking their names or using the Un Select all buttons below the lists Use the Update AOIs button under the slide list to hide all AOIs not present in the slides pages selected Based on the set of AOIs and recordings selected a number of different statistical measures can be calculated These statistics can be displayed either in a table by clicking the button Show Statistics in the bottom right section of the main view or as a chart by clicking the button Show Chart The Transition matrix in the AOI template shows how focus
58. ision studies and more To facilitate meaningful studies the software combines the collection and analysis of eye gaze data with numerous other data sources including key strokes external devices video recordings web browser activity and more ClearView also provides mechanisms to interface with other software Licenses The ClearView software may be installed on any number of computers in order to prepare studies and analyze results However recording of data can only be done when connected to a Tobu Eye Tracker and with a valid license key installed Any time ClearView is launched without a valid license key a dialogue is launched where a license key can be added License keys are distributed together with the hardware delivery To order a new license key contact sales tobii com For technical assistance contact support tobii com Providing the current serial number shown when an eye tracker is connected to the ClearView computer speeds up the process of making a new licens key x No valid license key found To make recordings with the Clearview software you need at least one valid license key To purchase a license please contact sales bobii com For technical assistance please contact supporti tobii com Existing License Keys Expiry Date AddOns New License Key Po Add key JK Figure 7 The serial number is needed to create a new license key With the basic ClearView license Image Slide show stimuli
59. key press instead e Label eg FirstSlide This is a label associated with each slide Data recorded During the presentation of the slide show eye gaze data is recorded For each slide transition a showslide event is saved to the event file This data contains a precise time stamp for when the event occurs the slide order number name and label Key strokes mouse clicks and responses from external game pads are also recorded into the event file allowing reaction times and subject responses to be measured 23 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Advanced issues Precision in slide timing Fast subject responses One common use of slide shows in eye tracking is reaction time studies Because of this the timing issues involved in stimulus presentation and data collection are very important Tobu have taken great care to provide timing precision for image presentation and use DirectX and pre loaded images to RAM to improve the speed of image presentation The time stamps of image presentations are accurate to approximately 2 ms However it should also be noted that the accuracy of the timing 1s only relevant to a certain point as the eye tracker itself has certain delays and the screen refresh rates may delay the showing of the images For a CRT monitor typical refresh times are in the order of 15 ms Since the slide presentation is not synchronized with the
60. libration dot A cross hair is displayed for each calibraiton point and space bar is used to forward between calibration points User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Background color Object color Normal Calibration settings Infant calibration settings Advanced 61 For maximum accuracy we strongly recommend setting the background of the calibration screen to a color which is close in light intensity to that of the stimuli used during recording If the calibration screen is very dark and the stimuli very bright a large degree of drift may occur which decreases the accuracy The default calibration background is suitable for most web site studies since they are generally rather bright Always set the object color to a shade which provides good contrast to the selected background Speed The speed for the normal calibration routine can be selected Dot size The size of the calibration dot for the normal calibration routine can be selected Big attention grabbing AVI A full screen AVI to redirect subject attention to the screen specified in Study settings as Attention grabbing AVIs Calibration AVI A small AVI displayed at the calibration point for calibration specified in Study settings as Calibration AVI Small attention grabbing AVIs small AVIs positioned at the calibration point but not used for calibration these AVIs shoul
61. location Coordinates for top left corner of the browser window x going left to right and y top down from the upper left corner of the screen e Browser size Defines the height and width of the browser window Note This is the origin and size of the whole browser window not the origin and size of the internal window showing the web page Design tip When performing usability studies a study is usually set up of a number of tasks that the subject should solve for example Find the contact information for the European sales office Splitting tasks into different stimuli will greatly improve the ease of managing and analyzing the data after the tests It is suitable to prepare one stimuli each for each of these tasks to enable later analysis to separate between them It is also possible to use different start pages for the different tasks Data recorded While the subject is browsing web pages eye tracking data is recorded If screen recording is enabled a video of the information presented on the subject s screen is also created based on the same principles as the Screen recording stimuli In addition to this a bitmap of each HTML frame on each web page is recorded each time any new frame is shown in the browser This bitmap can later be used for area of interest definitions gaze plots and hotspot plots Also information relating to web page transitions browser window positions HTML frame positions and scrolling is constantly rec
62. low Note When creating a new stimulus ClearView copies the AVIs or images used to define the stimulus to its data base The original files do not need to be available after this 21 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Choose stimulus template Slideshow ae O AY Video External Video Scene Camera Empty Stimulus p web Moving Bitmaps Image template Save stimulus as Next Cancel Figure 10 The Stimulus Wizard displays the different types of stimuli available Image stimulus Image stimuli are used to present a single image to the test subject This can be used for very quick and simple studies of gaze behavior for example in simple advertising studies or vision testing Preparing the image The following parameters are available for the stimuli e Show mouse pointer Specifies whether the test person will see the mouse pointer on the eye tracker screen during presentation of the stimulus e Back color Sets the color used for the background if your image is smaller than the screen This is set by clicking on the colored box immediately to the right of the Browse button e Image file Sets the image file to be used as your stimulus Use the Browse button to find your file Any GIF BMP or JPG file may be used e View time Sets the time the image will be displayed This feature is disabled when Until key press is selected e U
63. lsating dot two lines intersecting in the calibration point are displayed When the space bar is pressed the lines change color while calibration is performed and the lines move to the next calibration point Important note The calibration is performed after space bar is pressed Make sure the test subject doesn t move his her gaze at the sound of the key press Infant calibration The infant calibration uses small AVIs to capture the user s attention and then calibrates on the point where the AVI was shown These AVIs are defined in the ClearView Study settings Several AVIs that can be used for calibration are provided in the ClearView Sample pack available on the installation CD compliments of Scott Johnson at New York University ClearView can also display multiple attention grabbing AVIs if test subjects respond poorly or grow tired of a particular AVI These attention grabbing AVIs should be named 1 avi 2 avi and so on up to 9 avi and be placed in the Stimuli folder as defined in Global settings default is C Program Files Tobii ClearView Stimuli To control the calibration process the following keys are used Right arrow Displays the calibration AVI at the next calibration point If the calibration AVI is already visible a calibration is made on that point before proceeding to the next one Left arrow Pause Hides the calibration AVI or the full screen attention grabbing AVI Up arrow Displays the full screen atte
64. mation we instead recommend looking into some of the literature references found in the back of this document For details on how to create your own applications that communicate directly with the Tobu Eye Tracker or with ClearView please refer to the Tobii Software Development Kit manual For any uncertainties or questions always feel welcome to contact Tobii support at support tobii com or call us on number 46 8 663 60 03 The user manual is valid for the following product versions e Tobu 1750 Tobi x50 and Tobi ET 17 eye tracking systems e 6ClearView 2 6 0 analysis software System requirements The Tobit Eye Tracker runs on a PC with the Windows Operating system Windows 2000 service pack 3 or 4 or Windows XP service pack 1 or 2 The system can either be used in a single or double computer setup see more under the chapter Single or Double computer configuration If used in a double computer configuration one computer will host the eye tracker server and the other computer the application software for example ClearView The eye tracker computer needs Firewire and USB connections In order to work with a double monitor setup the ClearView computer needs a dual head graphics card A second keyboard and a second mouse may also be connected to the computer to facilitate simultaneous operator and subject control for instance in web studies At least one of the keyboards and one of the mice must in such cases be possible to
65. more about this in the document How to set up the Tobit x50 Calibrating a Scene Stimulus setup When calibrating a test subject for a real world setting with physical objects it is advisable to use the low vision calibration type see also the section Study Settings Data recorded During recording ClearView will record a complete video of the input from the scene camera Gaze data as well as key strokes mouse clicks and external trigger sionals will also be recorded Gaze coordinates are in the calibration grid and range from 0 0 to the resolution of the scene camera movie Important notes Minimizing The perspective calibration is intended to compensate for the parallax difference in angle from the calibration grid and the scene camera errors I However this only compensates for angles as seen in the stimulus plane If three dimensional physical objects are used as stimulus and these have a certain height that take them far away from the stimulus plane this will cause a parallax error The size of this error is related to the difference in point of view from the scene camera and the test subject Therefore to minimize parallax errors it is recommended to place the scene camera in an angle fairly close to that of the test subject for example slightly behind and to the side of the subject or immediately over the subject s head Recording The film clap icon brings up the Record view used to make recordings on stimul
66. moved between different AOIs for the recordings The bottom table shows the transitions in absolute numbers and the top table in percent A transition from one AOI to another is registered if a test subject has a fixation within the first AOI and then moves to the second AOI with out fixating on any other AOIs in between However fixations on general content blank part of slide picture are allowed between the AOIs There are several different statistical measures calculated in the AOI template These measures are Fixation count Gage time Average fixation duration Time to first fixation and Fixation order e Fixation count Unit 1 Number of fixations in the respective AOIs This measure is based on fixations as defined in the fixation filter in ClearView at the time of the Direct Excel export Combining consecutive fixations also effects this measure e Gaze time Unit ms The total time of all fixations in the respective AOIs e Average fixation duration Unit ms The average length of all fixations during all recordings on the respective AOIs e Time to first fixation Unit ms Time from the beginning of the recording until the respective AOIs were first fixated upon 53 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Fixation order Unit 1 The order in which the respective AOIs were fixated upon If an AOI turns up several times in the fixation path of the recording it i
67. ne group can also be dragged onto an empty segment of the time bar in which case a scene belonging to that group is created When a new scene group is created by clicking the button New Scene Group the movie frame currently visible is set as the static representation for this scene To change the static representation right click the name of the scene group choose Edit Scene Group and drag the time slider to the proper frame in the movie before clicking OK 47 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Important notes Exporting Scene definitions are not exported along with the recording data If scenes recordings from different computers are merged into one stimulus for analysis scenes can only be defined after the import has been completed The LiveViewer can be very resource intensive Reduce load by AOIs on AOIs can be defined on scene groups defined with the scene tool scenes but if the name of a scene group is changed the AOIs defined are lost Exporting data from ClearView Text export ClearView can export data from a number of sources in a variety of formats in order to use other software for quantitative data analysis To make a text export select the recordings that you wish to export you can export multiple recordings concutrently Then click on Text Export and select the data types you wish to export All data is exported as tab delimited text files The files
68. nerated by ClearView The data for each recording is pasted into each Excel sheet according to the same format and with the same information as the text exports described above If several recordings are exported these are placed in separate columns After the data has been pasted into Excel ClearView looks for a macro called init and if this is found calls this macro This macro can be used to start a Visual Basic script or similar 55 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 To get acquainted with creating DirectExcel templates look into the Visual Basic code for one of the samples provided by Tobii press Alt F11 in Excel The Observer 5 0 Export ClearView offers functionality for exporting recorded data to a format usable by The Observer 5 0 by Noldus By selecting which recordings to export and click the button Observer Export in the Analyze view The Observer Export dialogue is displayed In step one of the export browse and select The Observer s project file ocp format and media folder to export the data and media to In step two select codecs for AVI export and choose what to export in the movie file background image gaze data overlay or both Data exported from ClearView to The Observer is interpreted as follows Mouse and keyboard events are described by the CV User Action behavior class Keyboard events are further specified by the CV Keys modifier clas
69. nt damage to the eye tracker Turn on the computer last The Tobu x50 also requires careful setup of the eye tracker in relation to the monitor projector screen or physical objects serving as stimulus Read more about this procedure in the document How fo set up the Tobi x50 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Figure 3 The cable connections on the Tobii x50 From left to right Firewire USB and power Setting up the Tobii ET 17 Always power down your computer before connecting or disconnecting your Eye Tracker product Connect the Tobit ET 17 and the computer s Connect the four cables in the following order 1 Monitor connector 15 pins should be connected to graphics card of the application computer 2 Serial connector 9 pins should be connected to the serial port of the eye tracker computer It is vital that you use the serial port which is named COM1 for this cable this is usually the first serial port of the computer 3 Firewire connector should be connected to any Firewire port on the eye tracker computer 4 Power connector should be connected to the supplied 12V Powerbox power supply which should in turn be connect to a normal power socket cither 110 or 240V AC Make sure to connect the eye tracker to the same power socket as the computer which runs the TET Server Connecting the eye tracker and computer to separate power sockets may result in
70. ntil key press Displays the image unit the user presses a key This feature is disabled when View time is selected Data recorded During the presentation of the image eye gaze data is recorded Also key strokes mouse clicks and external trigger signals are recorded to the event file Slide show stimulus Slide show stimuli are used to present a sequence of images to the test subject and record information about eye gaze slide transitions and subject responses key strokes mouse clicks etc Typically slide shows are used in experimental psychology advertising studies and low vision studies to measure gaze behavior response times search patterns and more 22 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Preparing the slide show manually To create the slide show in ClearView the following parameters are defined e Show mouse pointer If selected the mouse pointer will be shown during stimulus presentation e Image file Sets the image file to be used as your stimulus Any BMP JPG WMF or GIF file may be used Use the Browse button to find your file This feature is disabled when Blank slide is selected e Blank Slide Used to display a blank slide This feature is disabled when Image file is selected e Color of background Sets the color used for the background if your image is smaller than the screen or if you use a blank slide This is set by clicking on the colored box
71. ntion grabbing AVI Keys 1 to 9 Displays the small attention grabbing AVIs 1 9 avi respectively Interpreting the calibration plot When the process is complete a calibration plot is displayed The plot is used to indicate the quality of the calibration Each of the calibration points that were shown on the screen during calibration is now displayed as a blue circle and each 36 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 calculated gaze data in relation to this is shown as a red or green line One plot is shown for each eye red for left green for right The calibration is of high quality if e There are red and green lines for each of the blue circles across the screen indicating that calibration data was collected for every calibration point e The red and green lines are very short indicating that the calibration data collected is accurate Right Eye Right Eye Figure 16 Two calibration plots One perfect to the left and one poor to the right If calibration data is poor or missing for certain calibration points ClearView will automatically suggest recalibration of these points by marking them with red squares To choose additional points to recalibrate simply click on these with the mouse Clicking the button Recalibrate starts a recalibration of the selected points Clicking the Accept button saves the calibration Real time gaze display The real time gaze display is
72. o maximize tracking ability follow the recommendations below e Avoid very strong sources of near infrared light e g direct outdoor sun light or strong halogen lights which may disturb the tracking engine e Avoid test subjects with bifocal or progressive glasses or narrow glasses with thick reflective rims One way to test if the glasses are too narrow is to test if the subject can see the eye tracker camera below the monitor without the rims being in the way e Some people have features obstructing a very large portion of the eyes for instance very low eye lids or thick mascara Such subjects should be avoided since this can cause difficulties in tracking One clear evidence of this is if you get a calibration only for the top or the bottom half of the screen e Ensure that subjects are sitting at the correct distance from the system when starting the study 60 cm especially when calibrating Tolerance to head motion The camera is fixed relative to the TFT screen and uses a very wide field of view This enables the system to tolerate fairly large head motions and record the relevant information about the subject even if he or she rotates or moves their head As long as the system is able to detect at least one eye of the user robust tracking of the gaze point is possible The field of view of the camera is about 20 x 15 x 20 cm width x height x depth at 60 cm from the screen Since it is enough that one of the eyes is within
73. of 120 ms Precision in time stamps Each gaze data is marked with a time stamp The time stamp is generated by a trigger signal sent from the eye tracker hardware and collected on the eye tracker computer using a special Tobit high resolution timer based on the Windows multimedia timer Since the basis for estimating the eye position is an image taken from a camera there is always a certain exposure time used to generate this image The time stamp is set to indicate the center of the exposure time which is the best theoretical estimation of when the image was taken Under normal computer load when the system is working at full speed this time stamp is accurate to 3 ms for the Tobii 1750 and 5 ms for the Tobii ET 17 Synchronization If the TET Server and the application run on the same computer no synchronization between them is required If they run on separate computers the server needs to synchronize with the application This is done automatically by the server and the application during the setup phase Once a connection has been established the application issues a synchronize command which starts an exchange of messages between the eye tracker server and the application This measures delays and clock deviations between the two machines During operation the TET Server knows how to re calculate time stamps so that they match the internal system time of the application This is accurate to less than 1 ms
74. oints Take the next potential fixation None of points in the potential fixation are actually part of a fixation the valid filtered gaze Is the duration of the potential fixation at least Y ms NO This is a fixation with the fixation centre as the average of the gaze points in the fixation and the fixation duration being the time from the first gaze point in the fixation to the last Continue with next algoritm Are there further potentia fixations Finished Figure 28 The fixation filter algorithm 64 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The ClearView Database All of the information in the ClearView system including stimuli subjects recordings AOI definitions and more is collected managed and saved into a database After the creation of a stimulus ClearView does no longer need access to the original files since copies are stored in the database The database is structured into a set of files on the computer which are not intended and in most cases not possible to read directly This ensures that the data is intact and well structured To alter rename move or delete files in the database structure may corrupt data recorded beyond repair To access the information obtained with the ClearView system using other applications and customized software there
75. ollowing chapters The screen recording is intended for recording low intensity graphics such as when the subject is browsing a web site or using a word processor For highly graphics intensive applications such as replaying a full quality movie or playing a computer game the AVI stimulus or the External video stimulus are recommended instead Preparing the screen recording There are no editable options when creating the Screen stimulus but the frame rate of the screen recording can be altered under the Recording tab in Global Settings Data recorded At the start of recording the ClearView screen is hidden and whatever is present on the computer desktop is shown The subject is free to use any type of application on the computer Eye gaze data is recorded as well as a movie of the screen contents Key strokes and mouse clicks are also recorded and saved in the event data file The screen recording video is recorded at full screen resolution Advanced issues Hardware The Screen Stimulus puts the same restrictions on acceleration and hardware acceleration and screen resolution as the Web Screen resolution stimulus trade offs 2a User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Moving bitmaps stimulus Moving bitmap stimuli is used to present one or several small pictures that move around the screen in various patterns defined in a script Typically moving bitmap stimuli can be used
76. oop it until a key is pressed or to progress either when the AVI is finished or a key is pressed Data recorded During the presentation of the AVI movie eye gaze data is recorded Times for the changes of played AVIs key strokes and mouse clicks are also recorded and saved in the event data file Important notes The AVI format is a standard format for movies including video and audio AVI files can contain compressed or raw data uncompressed but normally the files are compressed in order to get a reasonable size on the AVI file Compressed AVI files typically have sizes of 10 50 Mb per minute while uncompressed files normally have sizes of some 600 Mb per minute The AVI stimulus in ClearView is not intended for showing uncompressed AVI files Also the AVI stimulus only shows movie files in the AVI format and other types of movies have to be converted to AVI files There are several good video editing programs available that can be used to convert movies to the AVI format and to compress AVIs to a proper size Many of these can be downloaded for free from the Internet If you would like specific recommendations please contact Tobi support External video capture stimulus External video capture stimulus is intended to use when video data from a different source than ClearView is used as stimuli ClearView records a video input from most video sources as a movie which can later be used for gaze analysis Examples of common video sou
77. orded so that the gaze information in the analysis phase can be accurately correlated with the contents on each web page Key strokes and mouse clicks are also recorded and saved to the event file Important notes The Internet is a pretty messy place with a lot of different types of data being presented and a lot of dynamic behavior The recording mechanisms provided by the ClearView web recording tool have been designed to facilitate recording of a number of different events and information However there are exceptions where the tool does not record information correctly The below table shows details on which types of web content are correctly recorded in ClearView Type of Handled Comment content today Standard Yes All basic HTML content including text HTML pages tables bitmaps etc HTML frames Yes Infinite sub frames with or without scrolling for each frame I Frames No Will be handled in future versions of Clear View 23 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Pop up windows ASP generated pages Javascript and other script tools Flash animations Browser window size Page identifier Hardware acceleration No If your study allows it we recommend disabling pop up windows This can be done by downloading and installing a so called pop up stopper Yes If web pages are created using ASP and if they generete clean HTML they can be
78. permanent damage to the eye tracker Turn on the computer last Figure 4 On the back side of the Tobii ET 17 four cables are connected from left to right power serial Fire wire and monitor cables Note Always power down your computer before connecting or disconnecting your Eye Tracker product Make sure to connect the eye tracker to the same power socket as the computer which runs the TET Server Connecting the eye tracker and computer to separate power sockets may result in permanent damage to the eye tracker User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Installing the software See the Installation Manual found on the Tobii CD Make sure to re start your computer once installation is complete Adjusting your computer settings The first thing to do after installing the software and hardware is to ensure that the computer settings are appropriate for running eye tracking tests Screen resolution and colours In order to household computer resources it is important to optimize graphics settings Tobu s recommendation is to always use the same resolution and colour depth on both the subject eye tracker monitor and the operator monitor Also since using high resolution and large colour depth is very resource intensive it is recommended to limit these to a resolution of 1024x768 and a 16 bit color depth Changes to resolution and colour depth is done under control panel display
79. port The INTERACT export exports event data fixation data gaze data and data on which areas of interest have been fixated on to a format readable by INTERACT by Mangold along with gaze videos and user camera videos inreracr enpor ne Select data Files to export W AOI Data A01 W Fixation Data FO W Event Data EYO W Gaze Data GZD Select video Files to export Jv Gaze Video LAYI Jw User Camera Video LAVT Select Video Codec Microsoft video 1 Select Audio Codec MPEG Layer 3 Select Export Option Frame Rate Background and overlay data fis Export destination Browse Cancel Figure 26 ClearView can export data to INTERACT by Mangold 57 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Settings and data filters Settings in ClearView are divided into two logical parts G obal settings which include settings for physical setup of the hardware and data collection and Study settings which include settings for the conducting of a test including calibration and analysis The Study settings also include settings for the filtering of eye tracking data Global settings Global settings contain all settings associated with the hardware setup of ClearView or settings which are the same for all studies made The settings can be reached either by clicking the global settings icon in the toolbar or from the Settings menu Recording Stop recording ke
80. pture card Gaze data as well as key strokes mouse clicks and external trigger signals will also be recorded Important notes CPU load When performing video capture the video signal needs to be and timing converted from an analog to a digital signal Thereafter it needs to of the be captured and compressed into a movie Because of this delays captured are induced that affect the precision in timing of the video Also at video high CPU loads some video capture devices loose video frames occasionally This means that although gaze data and trigger data is timed with the same precision as for all other ClearView stimuli she synchronization of gaze data in relation to the captured video can be degraded This issue is partly related to CPU load Video capture consumes a lot of CPU resources as does the eye tracking itself Therefore the use of a two computer setup for the video capture stimulus is recommended Scene Camera stimulus The scene camera stimulus is intended to be used in combination with the x50 hardware when video data is collected from a physical scene using a stand alone camera This stimulus is very similar to the external video stimulus with the addition that it also performs a point of view compensation to compensate for the fact that the scene camera is placed at a certain angle relative to the stimuli and the user A typical scene camera setup will typically contain the following key items e Some sort of st
81. r and one machine is dedicated to the analysis or interaction application the application computer The two machines are connected via TCP IP For minimum latency in communication between the computers we recommend connecting the computers on a dedicated network i e not part of a larger office network The easiest way to do this is to use a cross over network cable to connect the two computers directly If the eye tracker is used for applications which are not very resource demanding the system works equally well and is easier to maintain on a single computer An example of such application is to use ClearView for basic slideshow studies In this case the eye tracking computer and the application computer are one and the same Once ClearView has been installed in Global settings on the Network tab Remote computer must be chosen ant the IP address to the eye tracker computer must be supplied If a crossover network cable is connecting the eye tracking computer and the application computer these need to be assigned fixed IP addresses manually using so called black addresses This is done by manually setting IP addresses beginning with 192 168 For example give one computer the IP address 192 168 0 1 and the other 192 168 0 2 To assign the IP address manually for a computer go into the Control Panel and open up Network Connections right click the proper connection typically a Local area connection and choose Properties Scroll down
82. rces are e Web cameras e Video capture cards for e g VCRs input e VGA capture cards This stimulus type is recommended when presenting stimuli with another software than ClearView e g E Prime or when doing eye tracking on other dynamical stimuli generated outside ClearView such as console games interactive television or resoutce intensive computer games played on another computer 30 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Preparing the external video capture To prepare the external video capture you first need to ensure that you have the proper hardware setup Your video source needs to be connected to a video capture card of the computer where ClearView is running Please refer to the System Requirements chapter or contact Tobi support for information on recommended video capture cards Egexternal Yideo Wizard Outside x TEE he External Video Define External video Stimulus Video Settings ideo Source ideo Image Logitech QuickCam PTZ Inputs x ideo Codec Microsoft Video 1 Camera Settings Use video as stimulus a OK Cancel Figure 11 The Stimulus wizard for External Video includes settings for Video source and quality In the prepare view for External video capture a number of settings defining the video to be captures can be defined e Video Source This needs to match the type of video source used Most video c
83. rest within your stimuli Instead of intepreting your data based on the direct gaze coordinates of the test subjects you base the analysis on the frequency time etc that the subject s have been looking within the areas of interest This is applicable to a 39 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 range of different analysis applications for instance psychology studies and web usability studies Defining can be done before but in most cases it is best done after you make your recordings Click on the Define AOIs button in the analysis view to enter the AOI definition tool You can create any number of AOIs in any frame of your stimuli A frame can either be a single image for image stimuli one of the slides in a slideshow for slide show stimuli an image of each frame visited during web browsing for web stimuli or a static image representing a whole AVI To define a new AOI select which slide to define AOIs select a frame in the top left list Add a new AOI either by right clicking the image and choose to create a new rectangular or polygon AOI or by clicking the rectangle or the polygon on the toolbar and then drag n drop the desired shape on the picture All AOIs can be moved around or resized by moving its corner points Figure 18 The AOI tool allows for definition of AOIs of any shape AOIs can also be grouped in categories This can be useful if several AOIs repre
84. s given the lowest order number of those instances E g if the fixations fall on AOIs in the following order A B A C A gets order 1 B order 2 and C order 4 There are different ways of grouping the data in the AOI template Grouping data in different ways can be useful in some cases when analyzing statistics Normally all data is grouped by slide showing e g how much time was spent on the different AOIs in the different recordings However grouping the statistics by AOI instead shows statistics on how much time was spent on any AOI in the different slides pages during the different recordings tobii technology Columns b Recording AQI ADI Measure to calculate Fixation count sare time Figure 24 The AOI template main view showing options for grouping data Next to the option of grouping the data in different ways in the AOI Template main view is an list showing what will be placed in the columns in the statistics sheet hence as different series of data in the chart sheet There are other options available in the AOI template Choosing information to show in charts defines what data to present as series in the data charts This option does not effect what data is shown in the statistics view Handle AOIs based on name groups together AOIs with identical names and treats them as one This can be useful in cases where identical or similar objects appear on different slides or web pages and should be analyz
85. s where each modifier corresponds to a unique key CV User Action Behavior Modifier Class CV Left Click CV Right Click CV Key Press CV Keys Image slide shows and AVI slide shows ate described by the CV Stimuli State behavior class Image slides are further specified by the CV Slide modifier class where each modifier corresponds to a certain image AVI slides are specified by the CV AVI modifier class where each modifier corresponds to an AVI file The behaviours in the CV Stimuli State class are mutually exclusive and exhaustive Web events ate described by the CV Browser Event behavior class The events are further specified by the CV URL modifier class where each modifier corresponds to a unique URL Fixation data is described by the CV Fixation behavior class The behaviours in the class are mutually excluswe and exhaustive Modifier Class 56 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 CV Fixation CV Non Fixation OO o oo AOI Data is described by the CV AOP behavior class The AOI names in ClearView are converted to new names formatted like CV AOI X where X is an index The real names can be found in the behavior descriptions The behaviours in the CV AOP class are mutually exclusive and exhaustive CV AOI Modifier Class CV No AOI is CV AO pe CV AOI 2 Pe CV AOIn pe INTERACT ex
86. s can The scene tool makes it possible to split recordings made with the AVI Scene External Video and Screen stimuli into scenes effectively making them into slide shows To make a movie into a slide show the movie is first divided into scenes and after that these scenes are grouped into scene groups This way scenes appearing in different order in different recordings or several times during one recording can be analyzed together in Hot Spots BJ Smi aiar ni i ar i TH Be pe s p r e e ie e 7 igus d4 7 Oo e87 4 sO geRore ETE ee ee E eee eee es er mee a Ds CER Peer EEN e tee ig i i Fri bri Flog Pim pi tak baja Hiph rme mailma em b gii op mir bme t pcs As i ad dii daa Hie ral t LAS mi daja pl bataar mda a Byrial aporte to TER RCT md Tha Qbasrsar Erien Yale a Daana Camara m i apara bedded ona aprit nee i Ct phi b a i ei ka i ie le ey ap ihe device i aie See of oe Te SOE lie a aa aed bel hedi Toe tee 0 air Al amaA an j Apel a m EE ap am i Figure 22 With the scene tool movies can be analyzed as slide shows To split a movie into scenes the movie is played and scene change markers are inserted by pressing Ctrl M on the keyboard Uncoloured time segments not belonging to any scene group appear on the time bar To attribute a scene group to a scene the scene group is simply dragged to the time segment on the time bar Drag either the name of the scene group or its colour to the time bar A sce
87. s that fit into a single cell The most important implications this has on data exported with the DirectExcel functionality are listed below 20 minutes of gaze data If gaze data is exported the maximum length of a recording is roughly 20 minutes which corresponds to the Excel maximum of 65000 rows 16 recordings of gaze Each recording takes up 16 columns for gaze data data Since Excel only has 256 columns a maximum of 16 recordings of gaze data can be exported 150 minutes of fixation If fixation data with an average of 7 fixations per data second is exported the maximum recording length is roughly 150 minutes corresponding to the Excel maximum of 65000 rows 51 recordings of fixation Each recording takes up 5 columns for fixation data data Since Excel only has 256 columns a maximum of 51 recordings of fixation data can be exported 52 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Using the AOI template The AOI template AOL _Template_1_x x s is a sample template provided by Tobit This template can be used to quickly and accurately calculate a number of basic fixation measures on afea of interest data from stimuli with Areas of interest AOIs defined The AOI Template can be found in the ClearView Sample pack available on the ClearView installation CD z i l P H Tobii Area of Interest Statistics Template tobii Maoile technology Salect slides to inckada Select recon
88. sent the same type of objects in the stimulus and need to be treated together in statistical calculations Create new categories by choosing New Category on the Category menu and chose which AOIs belong to what categories by choosing Edit Categories on the same menu and checking the appropriate checkboxes alo ADI Categories a ADI Mame ACT ID Dunes Pyramids Pyramid one Pyramid two a Pyramid three z F Iw cd Close dunes Mew Category Delete Category OK Cancel Figure 19 By grouping AOIs into categories statistical analysis is made even easier 40 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 If the same set of AOIs is to be used on several images they can be exported and imported using the Export Import AOIs options on the File menu in the AOI Definition tool For more information on how to use the results from area of interest analysis please refer to the Text export and Direct Excel export chapters below Important issues AOI buffer zones Errors in gaze estimation might be as large as one degree corresponds to about 30 pixels for 1024x768 screen resolution in normal conditions Therefore we recommend defining AOIs with a buffer zone of roughly 30 pixels around the intended object when this is possible Also avoid defining AOIs that are too small Gaze replay The gaze replay is a way to dynamically visualize
89. slides as well as collected events like key stroke and mouse click events external trigger events and more e Moving bitmap information Contains information about the screen position of the different bitmaps when the moving bitmap stimulus is used e Video and audio recordings Different files containing video and audio recotdings from screen recordings video capture etc e Web recording information Contains information about scroll events frame positions etc of web pages and more required for web studies e Analysis information and settings such as defined AOIs color and length of gaze trail and so on 65 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Editing studies and subjects To access the database functions of ClearView select Edit Database under the File menu To move an entire study between computers which is useful for doing prepration ot analysis on a different machine from the recording PC select the Study button and the Export tab Select the study or studies you wish to export and click the Export button This feature can also be used to backup your studies An exported study is placed in the specified folder and gets the file extension expst To export subjects together with their calibrations select the Subjects button and the Export tab Select the subject or subjects you wish to export and hit the Export button Clear View Database 0f x 9 Data
90. t to chosen Note Scene definitions are not exported along with the recording data If recordings from different computers are merged into one stimulus for analysis scenes can only be defined after the import has been completed Special Exports ClearView also offers export options to other programs which can be used for analysis of eye tracking data These special exports include export to Microsoft Excel The Observer by Noldus and INTERACT by Mangold The special export is found in the Analyze view of ClearView Direct Excel Export A powerful yet flexible analysis tool in ClearView is the DirectExcel export This enables quick export of data into a pre defined template in Excel This template may include formulas graphs and visual basic code to post process the data to generate a wide range of different statistics A set of pre defined templates are shipped together with ClearView The templates can be found in the folder DirectE xcel Templates in the Samples folder on the installation CD and on the Tobu web site To use a DirectExcel template select the recordings to analyze Click the Special Export button and choose Excel export Find the Excel template to use and click OK The data from the selected recordings are now inserted into the selected excel document and a macro in Excel is executed Excel limitations Excel has a number of built in limitations relating to the size of spreadsheets and the number of character
91. te stimuli with multiple bitmaps that move around according to individual patterns any number of scripts can be added to a single stimulus The script to appear on top of other scripts can be changed by using the arrow buttons in the Moving Bitmaps stimuli wizard Data recorded During the presentation of the moving bitmap stimuli eye gaze data is constantly recorded For each gaze data point the position on the screen of each bitmap is also recorded This will allow easy and powerful analysis of eye gaze position relative to the stimuli Also keystrokes mouse clicks and responses from external game pads are recorded into the event file which can be used to measure reaction times and subject responses Advanced issues Smearing For certain types of moving bitmap studies such as smooth pursuit effects on studies the smoothness of movement of the stimuli can be very TFT important monitors When using the Tobi 1750 or the Tobit ET 17 eye tracker the tests are always confined to a TFT monitor This has certain limitations in screen refresh rates In particular TFT monitors fade in and fade out the screen which cause a certain smearing of fast moving images When such issues ate crucial we instead recommend using the Tobit x50 hardware which allows stimuli presentation on a CRT monitor instead Avoiding Another issue related to screen behavior is jitteryness of motions jittery of the bitmap Tobi generat
92. that are created are given the name of the recording plus a short three letter word in capital letters indicating the type of file For example a gaze data recording with the name myfirstrecording is given the filename myfirstrecordineGZD txt All export files start with a header containing information about the recording date and time study name test subject name recording name screen resolution and coordinate unit used for gaze data The following text exports are available Gaze data GZD This exports the raw gaze data from each recording with the columns below Data column Description Number A sequential serial number given to the gaze point Time The timestamp in ms for this gaze point from the start of the recording Screen X left eye The horizontal position of the gaze point measured in pixels from the left Screen Y left eye The vertical position of the gaze point measured in pixels from the top Cam X left eye The horizontal location of the pupil in the camera image on a scale from 0 to 1 Cam Y left eye The vertical location of the pupil in the camera image on a scale from 0 to 1 Distance left eye The distance from the camera to the left eye in mm Pupil left eye The size of the pupil in mm Code left eye The validity of the gaze data 48 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Screen X right eye Screen Y right eye Cam X r
93. the eyes of the text subject As long as at least one of the subject s eyes are within the box the system can track eye movements For best results both eyes should be within the box It is also recommended to start each recording session by having the subject s eyes placed in the middle of the track status meter at about 60 cm distance This enables the subject to move as much as possible during the test without moving outside the box The text bar indicates the tracking ability If the bar is colored dark green with the text both and is not flickering the system is tracking the test subject well If the text bar is red or flickering between red yellow and green the system has difficulties tracking the particular subject for some reason In most cases this means that tracking will not be successful even though it is possible to try by continuing with calibration and recording Figure 15 The track status meter to the left shows perfect tracking while the one to the right indicates that only the left eye of the user can be found Calibration The calibration teaches the eye tracker the characteristics of a particular subject s eyes This is necessary for accurate estimation of a subject s gaze point Perform a calibration To calibrate a subject already added to the study go to the Record view choose the subject to calibrate from the subject list and click the Calibrate button After showing the track status meter th
94. the field of view this gives an effective tolerance to head motion of about 30 x 15 x 20 cm This is enough to compensate for any head positions which are comfortable when sitting in a normal posture in front of a computer screen When using ClearView for most gaze analysis purposes it is recommended to use a double screen configuration This allows the test leader to see the track status of the subject during a recording session By doing this the test leader obtains information as to where in the camera s field of view the subject s eyes currently are If the subject has moved too far the test leader can discretely instruct the subject to move into the field of view again To maximize the subject s comfort and ability to move during a test follow these recommendations e Use a steady chair with no wheels and a fixed back for the subject This will allow the subject to relax but automatically avoid large body movements If the chair can be easily raised and lowered this makes it easier to adjust for different subjects 16 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 e Start each session with the subject s eyes somewhat above centre of the track status meter and at a distance of 60 cm This since subjects tend to sink down in their seat during testing The tracker is unable to track eye movement if the head of the user moves too fast This is mainly due to smearing effects in t
95. tings Perspective Calibration ideo Source ideo Image Calibration Image Logitech QuickCam PTZ 7 ideo Codec f Microsoft video 1 7 Camera Settings Figure 12 The Scene stimulus is very similar to that of External Video After specifying the video capture settings a perspective calibration has to be made in order to correlate the captured vide to the physical world In order to define how this grid is positioned relative to the scene camera a perspective calibration is required This allows ClearView to re calculate all gaze data to accurately indicate where on the presented scene the subject has been looking To perform the perspective calibration first place the calibration grid on the surface to be tracked Then adjust the settings for your video characteristics as described above Use the preview pane to adjust the scene camera so that it captures the area on which eye tracking is to be conducted Fix the camera so that it cannot be accidentally moved and click the New button in the Calibration image section of the Stimulus wizard Calibration Image Figure 13 Perspective calibration is a crucial part of the Scene stimulus setup 33 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The scene camera now shows an image of the scene with a polygon drawn on top Adjust the polygon by dragging its corners so that these are precisely on the corner calibration points see
96. tion on the interpretation of the validity code The validity filter translates these validity codes to which eyes were reliably found The available settings for the validity filter are normal medium and high and they translate validity codes as described in the table below Left Right Result Result Validity Validity Normal Medium 0 0 The eye filter may be used to base gaze analysis on either of the eyes both eyes separately or on the average of the two eyes The choice here has important implications for many types of studies For most purposes we recommend using the average of the two eyes This is generally more accurate and more stable over long time and across changes in head position and light conditions For studies of where a person is looking this setting yields the most accurate results For studies of more physiological characteristics it is often interesting to study each eye individually or possibly to study them simultaneously to see difference in behavior between the two eyes For such purposes we of course recommend setting the eye filter to either left or right eye Another case where either eye may be a suitable setting is if the test subject has high gaze accutacy on one eye and low gaze accuracy with the other In such cases analysis should be performed only on the dominant and stable eye 63 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 20
97. tobii technology Web www tobii com E mail support tobii com Phone 46 0 8 663 6003 User Manual Tobii Eye Tracker and ClearView analysis software Contents User Manual Tobii Eye Tracker ClearView analysis software Contents Setting up the Tobii hardware and ClearView software Introduction System requirements Setting up the Tobii hardware Single or double computer configuration Single or double screen configuration Different system setups Setting up the Tobi 1750 Setting up the Tobii x50 Setting up the Tobi ET 17 Installing the software Adjusting your computer settings Screen resolution and colours Configure dual monitor setup Verify Internet explorer version Getting started Start the ClearView software Prepare your first study Make your first calibration Record your first recording Analyze your study The Tobii Eye Tracker System overview The Tobii eye tracking hardware Gaze data recording with the Tobii Eye Tracker Timing aspects of the system Frame rates Latency Precision in time stamps Synchronization Accuracy in gaze estimation Measured accuracy Drift effects Head movement compensation Tracking ability General tracking ability Tolerance to head motion Gaze angles Tobii Technology AB 2006 O CHM FM FP NAA KHANUSW Oo _ User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The meaning of validi
98. ty codes 17 Using the ClearView analysis software 18 Introduction 18 Licenses 18 Basic workflow 19 Prepare 19 Record 20 Analyze 20 The ClearView Sample package 20 The different stimuli types 21 Image stimulus 22 Slide show stimulus 22 Web stimulus 24 Screen stimulus 2I Moving bitmaps stimulus 28 AVI stimulus 30 External video capture stimulus 30 Scene Camera stimulus 32 Recording 34 Track status meter 35 Calibration 35 Real time gaze display 37 Live Viewer 37 Controlling ClearView from other applications 38 Analyzing data 39 AOI definition 39 Gaze replay 41 Gaze Plot 42 Hot Spot plot 44 Scene tool 47 Exporting data from Clear View 48 Text export 48 AVI export 51 Merging stimuli from separate studies 52 Special Exports 32 Settings and data filters 58 Global settings 58 Study settings 60 Data filters 62 The ClearView Database 65 Data types saved by the system 65 Editing studies and subjects 66 Literature References 67 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Setting up the Tobii hardware and ClearView software Introduction This user manual is intented to give an in depth understanding of how to use the Tobii Eye Tracker and ClearView software It does not aim to provide basic information about the nature of eye movements or guidelines on how to perform eye tracking studies for research or commercial purposes or to create and design eye control applications For such infor
99. uding a representation of the camera s field of view with two white circles representing your eyes Verify that the system automatically shows the position of your two eyes as white circles and the text bar showing a green light with the text both If this does not occur move until your eyes come into the view in the Track status meter Click on the Start button and look focused at the point moving across the screen It is not necessary to keep the head fixed during calibration When the process is complete a screen will be displayed showing the calibration result If there are red squares around one or mote blue circle click the Recalibrate button If not click Accept and assign a name to the calibration Record your first recording Select your stimulus in the left hand Stimulus area Select your name from the central Subject area Click on the Record button below the right hand Calibration area Verify that the system finds you as in section 3 above Click the Start button to start recording Look at the image for a period of time Press Space Bar to stop Analyze your study Select Analyze from the left hand toolbar Click on your stimulus name in the left hand Stimuli area Click on the small check box next to your recording name in the Recordings area Click the Gaze Replay button in the right hand Analysis area You should now be shown the gaze replay of your recording with your eye gaze replayed over your stimuli User Manual
100. vertising studies for example to measure task completion attention to different elements and to study fixation patterns Preparing the web stimuli You can setup the following parameters for web stimuli Start URL Sets the address of the web page your recording will start from There is no need to specify bip Use screen recording Controls if the subject s screen will be recorded to create movies of the web pages visited These screen recordings are the same as in the separate screen stimuli as described previously and is recommended for most web studies Without screen recording hotspots and gaze plots can still be made but gaze replay and AVI export are disabled analysis tools 24 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 e Block File download This blocks the browser to start downloading files to the hard disk if the user clicks a link which does that e Block Pop ups Since ClearView does not track the content of popup windows there is a built in pop up stopper in the ClearView browser e Show content during page download In some cases it might be important to know exactly when all the different parts of a web page were presented to the subject ClearView can download a requested web page in the background of the last page viewed and present it when it has been completely downloaded However this functionality is not compatible with certain types of Java menus e Browser
101. ving this box checked the users eyes will move to the same side as the gaze trail in the replay movie Gaze Plot The gaze Plot displays a static view of the gaze data for each image of the stimuli and is a useful tool when visualizing scan paths Each fixation is illustrated with a semi transparent dot where the radius represents the length of the fixation il Wee beyem ry Febri biud made fierra 1i L coer Fei eee M Figure 20 The Gaze plot visualizes the scan path of a user The left frames in the Gaze Plot window include a list of the frames displayed in the chosen recording and basic information about the selected frame By moving the mouse cursor ovet a fixation additional information about the fixation is displayed On the bottom of the Gaze Plot window a time axis shows when the current frame was displayed in time blue segments and what time segment fixations are drawn for red rectangle By dragging the edges of the red rectangle the fixations displayed will change accordingly For more details about how fixations are calculated read the section on Study Settings 42 User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 The Gaze Plot tool includes the following menus File Menu Save image Exit View Menu Full screen Edit Menu Copy image Settings Menu Color and Transparency Start numbering from one AOI settings Saves the Gaze Plot image to file The s
102. y Esc or F10 Screen recording frame rate Monitor Monitor mode single or dual screen Show Trackstatus on both screens Live Viewer Show Screen capture UserCam Track status Full Screen Save UserCam and UserSound files 58 This universal key will always stop the current recording in ClearView The default setting is F10 Make sure that the key used can not be confused with other keys or pressed by the subject during recording The frame rate of the screen capture in web recording and screen recording Note that screen recording is extremely resource intensive and that keeping the frame rate low is of essence For most applications it is recommended to stay below 10 fps Decides if ClearView will use one ot two monitors In double monitor mode the subject is presented with only the stimulus while the operator will see all controls and the Live Viewer When this option is checked the Track Status meter is shown to the test subject as well as to the operator Defines what to show in the Live Viewer and if the Live Viewer is to be displayed in full screen during recording Specifies whether the UserCam picture and or User Sound is to be saved to file for later analysis and or export User Manual Tobii Eye Tracker and ClearView analysis software Tobii Technology AB 2006 Video source Inputs Video Codec Camera Settings Video Settings Audio Source Network Tobu Eye Tr

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