Eye Link II System Introduction and Basic Training Session

1. Eye Link II System Introduction and Basic Training Session SR Research Ltd. Mississauga - Ottawa, Canada

2. Functional System Overview System Architecture Eye Tracking Experiment Process Software Architecture EyeLink EDF Data/Data Viewer EyeLink Gaze Overlay EyeLink Support Agenda

3. Functional System overview • Binocular / Monocular • 250 / 500Hz • Corneal Reflection vs. Pupil Only • Head tracking / Head-free Recording • Real-time Data Access • Windows API and Experiment Builder

4. EyeLink II High Speed Eye Tracking System • EyeLink II Key Features • High Speed – Binocular Recording at sampling rate of 250 or 500Hz. • Exceptional Resolution <0.01°, and low noise <0.01° RMS. • Accurate - Average gaze position error <0.5°. • 2 Modes of Operation - Pupil-Only or Pupil-Corneal. • Headband assembly is lightweight robust and ergonomic. • Compatible with most eyeglasses and contact lenses. • Easy Set-up, Calibration, and Validation. • Real-time operator feedback. • Online analysis of data into saccades, fixations, and blinks. • Powerful Application Programming Interface (API). • Compatible with EyeLink I applications.

5. System architecture • Host PC Data flow / integration Display PC

6. Runs on ROM DOS environment Performs image analysis, eye event parsing, and data recording functions Allows the system operator to view real-time gaze position overlaid on a static display representation while data recording is being performed Allows preference selection, camera setup, calibration, and recording functions Facilitates for the selection of 5 different calibration types (3pt - 13pt) Host Application

7. Integrates calibration, gaze position collection, head position compensation, and saccade and fixation analysis into one step Gaze position is overlaid on experiment graphics in real time, allowing validation of calibration accuracy before recording and monitoring of data quality during data collection Perform drift correction at any time Time stamped experiment event messaging; Dedicated Ethernet connection between Host and Display so no data is lost Allows the user to focus on stimulus presentation and data analysis Display API

8. Eye Tracking experiment process • Pre-Experiment activities • Participant setup • Calibration • Validation • Running the experiment • Drift correction • Trials • Blocks • Recording and Data Acquisition • Data analysis

9. Pre-Experimental Activities • EyeLink II is provided with several system configuration (.ini) files, which are designed to help the Experimenter control the tracker. • Before starting recording eye movements, it is critical to properly set-up the eyes and head cameras, and to calibrated/validate the subject. • A poor system set-up will result in a low data accuracy. • One of the most useful screens is called Set Options. Often it is overlooked.

10. Pre-Experimental Activities

12. Participant Setup - Headband The Headband placement becomes a smooth and fast procedure with practise: learn on yourself and test on colleagues before running an experiment. It should take less than 2 days of practise.

13. Participant Setup- Eye Cameras

14. Participant Setup - Head Camera Please, adjust the monitor or participants height till you reach this result

15. Participant Setup - Optimal Eye View Too Far Too Close Camera too High Camera too Low Optimal Pupil too High Pupil too Low

16. Participant Setup - Eye in Focus Not focused Focused

17. Participant Setup - Eye Threshold Fig. 1 The pupil threshold can be adjusted automatically, through the Auto-threshold command, or manually, through the up/down arrow. A threshold too low will result in shadows (fig.1), while a threshold too high will result in a noisy signal (fig. 2). Fig. 2

18. Experiment Setup • Calibration

19. Experiment Setup • Calibration poor • Good

20. Experiment Setup • Validation

21. Experiment Setup • Validation • Good • Poor

22. Running Experiment • Trials: • Smallest unit or presentation of a display • Try to perform a drift correction for each trial • Blocks: • Many trials make up a block. • Try to arrange a short break between blocks and check whether re-calibration is necessary. • Data Recording • Data Analysis – Selective filtering based on application

23. Running Experiment • Drift correction

24. Running Experiment • Avoiding Large Drifts • Headband slippage • Make sure that headband is not placed too far forward • Suspend the cable from above the subject or clip it to the back of the subject's collar • Head or Body Movements • Sit still and avoid major head/body movements • Use chin-rest • Supply a comfortable, stable chair • Pupil Occlusion • Check the positions and alignments of the camera and subjects' eye positions

25. EyeLink Recording Data • EDF File • Use EDF2ASC converter to get ASC file • Use EyeLink Data Viewer for analysis • What’s recorded? • Samples • Events • Messages • Buttons • Saccades • Fixations • Blinks

26. EyeLink Recording Data ASC File structure MSG 62792716 TRIALID PIX1 Normal START 62797388 RIGHT EVENTS PUPIL AREA EVENTS GAZE RIGHT TRACKING P FILTER 2 SFIX R 62797396 MSG 62797517 3 DISPLAY ON MSG 62797517 SYNCTIME 3 BUTTON 62797525 5 0 EFIX R 62797392 62797858 470 510.5 382.8 1813 SSACC R 62797860 ESACC R 62797860 62797914 58 503.6 385.5 429.2 128.3 7.97 194.9 SFIX R 62817356 MSG 62817515 TIMEOUT EFIX R 62817356 62817614 262 760.0 19.1 1465 END 62817622 EVENT RES 35.57 36.17 MSG 62817636 TRIAL_RESULT 0 MSG 62817636 TRIAL OK

27. EyeLink Recording Data • Samples: • System time, x, y and pupil size • With additional velocity, resolution, and CR status 63636348 511.1 383.3 1215.0 513.4 385.9 1622.0 ..... 63636352 510.8 382.6 1216.0 513.4 385.9 1623.0 ..... 63636356 510.0 382.5 1218.0 513.5 386.1 1624.0 ..... 63636360 510.0 382.3 1219.0 513.4 386.3 1625.0 ..... 63636364 510.1 382.1 1220.0 513.4 385.8 1626.0 ..... 63636368 510.3 382.3 1220.0 513.4 385.8 1627.0 ..... 63636372 510.4 382.4 1221.0 513.5 385.9 1631.0 ..... 63636376 510.6 382.6 1221.0 513.8 386.2 1630.0 ..... 63636380 510.9 382.6 1221.0 514.0 386.2 1629.0 ..... (Please read chapter 4 of the user manual)

28. EyeLink Recording Data • Saccades: • SSACC: eye, start time • ESACC: eye, start and end times, duration, start x/y, end x/y, saccade size, and additionally peak velocity, resolution SSACC L 63644396 SSACC R 63644396 ESACC L 63644396 63644424 32 646.9 219.5 853.9 194.8 6.16 394.8 ESACC R 63644396 63644424 32 659.3 212.7 859.6 191.9 5.96 385.6 (Please read chapter 4 of the user manual)

29. EyeLink Recording Data • Fixations: • SFIX: eye, start time • EFIX: eye, start and end times, duration, average x/y, pupil size, and additionally, resolution SFIX L 63644800 SFIX R 63644800 EFIX R 63644800 63645136 340 150.7 277.4 1853 EFIX L 63644800 63645136 340 134.3 277.7 1518 (Please read chapter 4 of the user manual)

30. Data Viewer

31. Three different viewing modes Spatial, Temporal and Gaze Cursor Playback Output detailed reports Fixation, Saccade, Interest Area, or Trial Export Data Views as JPG images Import multiple recording files into one viewing session Supports EyeLink I, II, 1000/2k, and Remote EDF files Fully integrated with API Data Viewer

32. Data Viewer

33. Data Viewer • Generate detailed Fixation, Saccade, Interest Area and Trial reports for further analysis

34. Create ‘Interest Periods’ to analyze data within a specified period of time Define ‘Reaction Time Definitions’ for automatic trial by trial reaction time calculation Data Viewer Monitoring eye data over time

35. EyeLink Support For more detailed information on our products and services, visit our website on www.sr-research.com or www.sr-support.com Send us an email support@sr-research.com or call toll free 1-866-821-0731(North America Only)

36. EyeLink Support

37. We will take a short break. Then it’s your turn to get eyetracking!