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EyeLink II User Manual

Head fixed eye tracker
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EyeLink
II Head Fixed Eye Tracker

User Manual

Version 2.12
Copyright © 1997-2006, SR Research Ltd.
EyeLink is a registered trademark of SR Research Ltd, Mississauga, Canada.

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Summary of Contents for EyeLink EyeLink II

  • Page 1: User Manual

    ® EyeLink II Head Fixed Eye Tracker User Manual Version 2.12 Copyright © 1997-2006, SR Research Ltd. EyeLink is a registered trademark of SR Research Ltd, Mississauga, Canada.

  • Page 2: Table Of Contents

    Analog Data Types................33 An EyeLink II Tutorial: Running an Experiment ..........35 The Camera Setup Screen ..............36 Adjusting Eye Camera Position ............37 Setting Pupil Threshold ..............40 EyeLink II User Manual (07/02/2006) © 2002-2006 SR Research Ltd.
  • Page 3 Pupil Size Data .................... 66 4.4.4 Button Data....................66 Events ....................66 4.5.1 Messages ....................67 4.5.2 Buttons ......................67 4.5.3 Eye Movement Events................. 67 Setting File Contents ................71 4.6.1 Sample Data....................72 EyeLink II User Manual (07/02/2006) © 2002-2006 SR Research Ltd.
  • Page 4 Limited Hardware Warranty ............... 94 Limited Software Warranty ..............95 Copyrights / Trademarks ..............95 Appendix A: Using the EyeLink II Analog and Digital Output Card....96 Analog Data Quality ................96 Setting up the EyeLink II Analog Card ..........97 8.2.1...
  • Page 5 Scaling of Analog Position Data ..............99 Pupil Size Data................. 100 Time base and Data Strobe............... 100 8.5.1 Strobe Data Input ..................101 8.5.2 Over sampling and Toggle Strobe............. 101 EyeLink II User Manual (07/02/2006) © 2002-2006 SR Research Ltd.
  • Page 6 List of Figures Figure 1-1: Typical EyeLink II System Configuration ........2 Figure 2-1: Screen Overview of EyeLink II Tracker Program ......9 Figure 2-2: EyeLinkII Offline Screen............... 10 Figure 2-3: EyeLink II Camera Setup Screen ..........12 Figure 2-4: EyeLinkII Set Option Screen ............16 Figure 2-5: EyeLink II Calibration Screen............
  • Page 7 Entela, an independent testing body. CONTACT ADDRESS SR Research Ltd. 5516 Main St., Osgoode, Ontario, Canada K0A 2W0 Fax: 416-352-5376 Phone: 613-826-2958 Toll Free Phone: 1-866-821-0731 (North America Only) http://www.eyelinkinfo.com/ EyeLink II User Manual (07/02/2006) © 2002-2006 SR Research Ltd.

  • Page 8: Introduction

    This section introduces the EyeLink II system, technical capabilities, and supporting documentation. IMPORTANT: Be sure you have read and agree to the end user license agreement provided in section 7.2 of this document before using the EyeLink II system. NOTE: Please be sure to check http://www.eyelinkinfo.com/news.php...

  • Page 9: Eyelink ® Ii System Overview

    The EyeLink II system consists of two miniature cameras which are mounted onto a head restraint. No mirrors are used in the EyeLink II system, making it very robust and easy to set up. Two eye cameras allow binocular eye tracking or easy selection of the subject's dominant eye without the mechanical reconfiguration required by most eye trackers.

  • Page 10: Eyelink Ii Host Pc

    1.3.1 EyeLink II Host PC The EyeLink II Host PC performs real-time eye tracking at 250 or 500 samples per second, while also computing true gaze position on the subject display. On- line detection analysis of eye-motion events such as saccades and fixations is also performed.
  • Page 11 C source code, and instructions for creating experimental applications are provided in the EyeLink II Windows developer kit. DOS and MAC API’s are also available on request. The Display PC has the following key attributes: • Runs experiment application software for control of EyeLink II tracker and stimulus presentation using EyeLink II API, allowing development of extensive experimental paradigms.

  • Page 12: Eyelink Ii Pci Card

    1.3.3 EyeLink II PCI Card The EyeLink II PCI card performs the powerful image processing required to achieve the high temporal and spatial resolution capable with the system. The PCI card is hosted in the Host PC and has connectors for: •...

  • Page 13: Physical Specifications

    CISPR 11:1997 and EN55011:1998 -- Class A, Group 1 ISM (Industrial, Scientific, and Medical) Equipment EN 60601-1-2:1993 – Part 1: General Requirements for Safety-Collateral Standard Electromagnetic Compatibility-Requirements and Tests. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd.
  • Page 14 WARNING: Changes or modifications not expressly approved by SR Research Ltd. could void the user’s warranty and authority to operate the equipment. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd.

  • Page 15: Eyelink Ii Tracker Application Operation

    Start your Host PC b) If your system was installed with BootMagic, select the EyeLinkII partition c) If the EyeLink II Tracker program does not automatically start, type the following at the command prompt: cd eyelink2\exe [ENTER] eyelink2.exe [ENTER] The EyeLink II Tracker application should start and display the Offline tracker screen.

  • Page 16: Eyelink Ii Tracker Application Navigation

    Analog output options are configurable via the “Set Options” screen and in the analog.ini initialization file. b) File Output. Eye data is available in the EyeLink II EDF file format. This can be converted to an ACSII file format using the edf2asc conversion utility.

  • Page 17: Offline Screen

    Camera view with threshold status Figure 2-2: EyeLinkII Offline Screen 2.3.1.1 Purpose The off-line mode is the default start-up screen for EyeLink II. The main secondary screens can be accessed via the navigation buttons on the left hand side of the screen.
  • Page 18 Press to view the Help screen, in the help screen there is a brief overview of the role of this page and the key functions for it. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 11...

  • Page 19: Camera Setup Screen

    Figure 2-3: EyeLink II Camera Setup Screen 2.3.2.1 Purpose This is the central screen for most EyeLink II setup functions. From this screen the eye and head tracking cameras can be set up, and their images can be thresholded. Eye(s) to be tracked, tracking mode and options can also be set.
  • Page 20 Here the Right Eye camera is selected. Image thresholds and status are indicated below each thumbnail. Keys: ⇐ and ⇒ to move left or right on image row EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 13...
  • Page 21 Keys: F1 = open Help screen Select Calibration to go to the Calibration screen. After setting up the eye cameras and thresholding, you need to Calibrate the system. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 14...
  • Page 22 Open the Help dialog, in the help screen there is a brief overview of the role of this page and the key functions for it Go to the Offline screen or exit camera setup EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 15...

  • Page 23: Set Options Screen

    This is useful when doing manual recording sessions that are not driven by a Display PC using the EyeLink II API. When using the EyeLink II API to drive stimulus presentation, these settings are normally set by the Display application via a set of API calls.
  • Page 24 The Diameter is recorded in millimeters. Keys: S = toggles Pupil size Area or Diameter Select Eye Event Data to record the Gaze or HREF of the participant. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 17...
  • Page 25 Select Events to record eye Events to the EyeLink II Data File. Keys: F = toggles File Data Contents Save the eye position in direct to the EyeLink II EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 18...
  • Page 26 EyeLink II settings specified in the defaults.ini file. Keys: L= Revert to last configuration from last session. Keys: D= Loads default configuration. 2.3.3.3 Key Shortcuts Function EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 19...
  • Page 27 Return to previous screen HELP screen Revert to configuration from last session. This is still saved even when the PC is turned off. Load default configuration (Default.ini) EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 20...

  • Page 28: Calibration Screen

    The eyes to be calibrated as well as the calibration type (as defined in the Set Options screen or via the EyeLink API) are indicated beside the camera images at the bottom of the screen. The calibration status and current calibration point being presented are indicated on the bottom right of the screen.
  • Page 29 Auto calibration set to the pacing selected in Set Options menu. (Auto trigger ON). EyeLink accepts current fixation if it is stable. After Calibration Help screen ENTER Accept calibration values Validate calibration values Discard calibration values EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 22...

  • Page 30: Validation Screen

    “Accept Fixation” button, or the ENTER or Spacebar key, to start the validation. If auto trigger is not enabled, repeat this action after each target fixation. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 23...
  • Page 31 Auto validation set to the pacing selected in Set Options menu. (Auto trigger ON). EyeLink accepts current fixation if it is stable. After Validation Help screen ENTER Accept validation values Validate validation values Discard validation values EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 24...

  • Page 32: Drift Correct Screen

    If the drift correction error is too large, the drift correction will be performed again. If the total drift since the last calibration is too large, the drift correct will fail and you will be prompted to perform another calibration. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 25...
  • Page 33 Keys: = ENTER 2.3.6.3 Key Shortcuts Function ENTER Begins or accepts Rejects drift correction value if one has been created or exits drift sequence. Help screen EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 26...

  • Page 34: Output Screen

    2.3.7.2 Main Functions Press to go to the Previous screen. Keys: ESC = Previous Screen EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 27...
  • Page 35 Press to Open Data File Keys: O = Open File 2.3.7.3 Key Shortcuts Camera Setup Screen ENTER or O Start recording Set options screen Help screen Opens EDF File EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 28...

  • Page 36: Record Screen

    2.3.8.2 Main Functions Stops the recording of data to the EyeLink Data File. Keys = ESC EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 29...
  • Page 37 Abort trail menu After Trail Aborted Setup (Calibrate, camera setup) Repeat Trail Next Trail CTRL + ALT + T Terminate Experiment CTRL + ALT + Q Terminate program EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 30...

  • Page 38: Status Panel

    ‘Pupil’ label in the Status Panel. All status flags remain on for a minimum of 200 msec, even if the condition that caused the warning or error to be raised lasted for less than 200 msec. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 31...

  • Page 39: Mouse Simulation Mode

    2.5 Mouse Simulation Mode You can use a mouse on the EyeLink II Host PC to simulate an eye to practice calibration and tracking alone or to test experiments during development is a test subject is not available. Select “Mouse Simulation” in the “Set Options”...

  • Page 40: Analog Data Types

    This measurement is the raw pupil-center position (or pupil minus corneal if running in pupil-CR mode) as measured by the image-processing system. This measurement is available without performing an eye- EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 33...
  • Page 41 The EyeLink II system offers integrated data recording and digital data transfer methods, which do not suffer from the timebase, resolution, and noise degradation inherent in analog systems. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 34...

  • Page 42: An Eyelink Ii Tutorial: Running An Experiment

    Display PC. The advantage of the Display PC based control is that it allows the operator to work near the subject, or for self-setup. We will perform most of the EyeLink II setup by using the Host PC keyboard.

  • Page 43: The Camera Setup Screen

    Figure 3-1: Example Camera Setup Screen before Camera Setup. Throughout the EyeLink II software, you can use the Host PC mouse to select options and navigate throughout the tracker screen. Almost very button has an equivalent key shortcut. The key shortcut mappings available for the currently displayed screen can be accessed via the Help button, or by pressing F1.

  • Page 44: Adjusting Eye Camera Position

    In TRACK, you can use keys on either the subject or operator PC’s to perform all keyboard shortcut operations while the eye image is displayed. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 37...

  • Page 45: Figure 3-2: Size And Vertical Eye Camera Adjustments

    Slide the camera up or down through the rod clamp gently, adjusting the vertical position of the image to keep the eye in view. Remember to re-tighten the rod clamp after the adjustment. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 38...

  • Page 46: Figure 3-3: Horizontal Adjustments Of Eye Camera

    This may require some practice: try setting up the headband on yourself, while watching the display on the operator monitor. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 39...

  • Page 47: Setting Pupil Threshold

    Eyeglasses also can show bright images of the IR markers mounted on the subject monitor. These reflections are automatically reduced as much as possible by the EyeLink II system; however not every subject with glasses will be usable. Position the camera as close to the subject’s glasses as possible to reduce noise.

  • Page 48: Figure 3-5: Symptoms Of Poor Pupil Threshold

    Pupil position can be seen by looking for the moving letter (‘L’ for left pupil, and ‘R’ for right pupil) in the data display EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 41...

  • Page 49: Calibration

    3.4 Calibration The preceding steps set up the EyeLink II camera system to track the positions of the pupils of both eyes. Almost all eye-movement research requires information on the subject's point of gaze on a display of visual information, such as a screen of text.
  • Page 50 A calibration target will appear on both the Host PC display and the Display PC monitor. The subject display is drawn by the TRACK.EXE application, in response to commands from the EyeLink II system. The Host PC display will also display the raw pupil position as a moving colored circle, and a thresholded eye camera image.
  • Page 51 The proper timing is best learned by watching the gaze cursor during validation (discussed later). The EyeLink II system helps prevent improper triggering by locking out the ↵ key if the eye is moving. Sometimes the ↵ key will be locked out because of poor eye-camera setup, with the pupil noisy or undetected in some positions.

  • Page 52: Figure 3-7. Calibration Grid Following A Good And Poor Calibration

    “Accept” button or the ↵ key to accept the calibration results. Pressing the “Restart” button or the ‘ESC’ key will restart the calibration. Pressing ‘ESC’ twice exits to the Camera Setup screen. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 45...
  • Page 53 Indicates Status of IR Markers OK = IR-Markers visible to camera. MISSING = at least one IR-Marker is missing from view CONFIG = Extra IR-Marker artifact detected EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 46...

  • Page 54: Validation

    (difference between target position and computed gaze position) is estimated. Note: since EyeLink II tracker version 2.0, a scaling factor is built in for automatically generated validation point positions to pull in the corner positions (see the command setting in the calibr.ini file).
  • Page 55 The average of this bias can be used to correct future gaze-position calculations, lowering tracking error. By accepting the validation the system performs a gaze calculation correction (similar to a drift correction) using this data. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 48...

  • Page 56: Recording Gaze Position

    This serves as a reference for the gaze-position cursor displayed by EyeLink II during recording, allowing the operator to see where the subject is looking and detect problems with eye-tracking errors or of subject inattention.
  • Page 57 Alternative, an online drift correction can be performed with the aid of a mouse click. Before recording, add the following line to the final.ini file: Normal_click_dcorr = ON EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 50...

  • Page 58: Exiting Eyelink Ii

    Check the head camera image for missing markers and position • Press ‘C’ to start calibration, press ‘ENTER’ to collect first fixation, let sequence. Press ↵ to accept result, ‘ESC’ to repeat. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 51...

  • Page 59: Experiment Practice

    This flow allows little room for practice, and makes it important that initial setup and calibration be performed correctly and carefully validated. The EyeLink II tracker has a trial-abort menu built in, which may be used in experiments to terminate trials where setup problems are seen. The Setup menu may then be used to fix eye setup or calibration, and the interrupted trial may be restarted or skipped.
  • Page 60 Using a dialog box built into the eyelink_exptkit library, ask for a file name for an EDF data file, which it commands the EyeLink II tracker to open on the Host PC hard disk. Run a block of trials. Each block begins by calling up the tracker’s Setup menu screen, from which the experimenter can perform camera setup, calibration, and validation.
  • Page 61 These require high sampling rates and low delay, which the EyeLink II tracker can deliver through the link.
  • Page 62 The final fourth block presents a white dot, a few seconds later another white dot is shown. The original white dot then fades away. This presentation pattern is repeated. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 55...

  • Page 63: Data Files

    4. Data Files The EDF file format is used by the EyeLink II tracker and supporting applications to record eye-movements and other data. It is designed to be space-efficient and flexible, allowing for complete records of experimental sessions and data. It adapts to monocular and binocular recording, with backwards-compatibility for future enhancements.

  • Page 64: Recording Edf Files

    Special provisions must be made for display of the calibration pattern. By using the EyeLink II tracker’s Output Screen, files may be opened and closed, and recording sessions may be started and stopped. Refer to Chapter 2 of this manual “EyeLink II Tracker Application Operation”...

  • Page 65: Parser Limitations

    4.3.3 EyeLink Parser Configuration The saccadic detection parameters for the EyeLink II on-line parser may need to be optimized for the type of experimental investigation being performed. For example, neuro-psychophysical researchers may need to detect small saccades amid pursuit or nystagmus, while reading researchers will need to detect only large saccades and will want fixation durations maximized.

  • Page 66: Parser Data Type

    Once correct parameters are determined, they can be set by EyeLink II commands over the link as part of the experimental setup, or the EyeLink II configuration file PARSER.INI can be edited to change the default parameters.

  • Page 67: Pursuit Thresholds

    This is acceptable for file data, but is expensive for real-time systems using data sent via the link. Fixation updates solve this problem by sending updates on eye position, pupil size, EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 60...

  • Page 68: Other Parameters

    0.6°. The psychophysical configuration is useful for neurological and smooth-pursuit research, and reports very small saccades. It also better estimates saccade durations and average velocities. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 61...

  • Page 69: File Data Types

    Samples are records of eye-position, pupil size, and button or input states. The EyeLink II tracker can record up to 500 samples per second, from one eye (monocular) or both eyes (binocular). Each sample is stored as a binary record in the EDF file, with simple compression used to minimize disk space.

  • Page 70: Position Data

    Other types of sample data are discussed in greater detail below. 4.4.2 Position Data Eye position data is produced by the EyeLink II tracker for one or both eyes every 2 or 4 milliseconds depending on the tracking mode and speed set. It is then processed to compute eye rotation angles and to compensate for subject head motions.
  • Page 71 HREF position per degree of visual angle: xres = 0.01745 * (f*f + x*x + y*y) / sqrt(f*f + y*y); yres = 0.01745 * (f*f + x*x + y*y) / sqrt(f*f + x*x); EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 64...
  • Page 72 The units are in actual display coordinates (usually pixels) which can be set in the EyeLink II configuration file PHYSICAL.INI. These are the most useful coordinates for most applications, but may not reflect true eye-rotation velocities due to head movements.

  • Page 73: Pupil Size Data

    4.4.3 Pupil Size Data Pupil size is also measured by the EyeLink II system, at up to 500 samples per second. It may be reported as pupil area, or pupil diameter. The pupil size data is not calibrated, and the units of pupil measurement will vary with subject setup.

  • Page 74: Messages

    Each button event records a change in state (pressed or released, 1 or 0) of up to 8 buttons or input port bits, monitored by the EyeLink II tracker. Button ports, bits, and polarity may be set in the EyeLink II tracker configuration file BUTTONS.INI.
  • Page 75 Other data is given on following SAMPLES, EVENTS, PRESCALER, etc. lines. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 68...
  • Page 76 The data contained in STARTFIX and ENDFIX events may be configured by modifying the DATA.INI file for the EyeLink II tracker. For most research, only simple fixation statistics are required, such as average position and pupil size.
  • Page 77 The peak and average velocity data for saccades is especially valuable for neuro- psychophysical work. These are the absolute velocities measured as the Euclidean sum of x and y components. The EyeLink II parser computes velocity by use of a 5-sample moving filter, which is equivalent to a differentiator followed by a 2-sample moving average, or a 63 Hz single-pole filter.

  • Page 78: Setting File Contents

    Setting File Contents The data recorded in samples and events may be set in the EyeLink II configuration file DATA.INI, or by sending commands to the tracker across the link, via the API eyelink_timed_command(). Similar commands exist for samples and events sent over the link for real-time applications.

  • Page 79: Sample Data

    The default data is: file_sample_data = LEFT,RIGHT,GAZE,GAZERES,AREA,STATUS Usually, data for both eyes is enabled, and the menus in the EyeLink II tracker are used to set which eye(s) are used. Recording of gaze and pupil area is essential for mast work, and resolution is important if velocity is to be computed later.

  • Page 80: Event Types

    The "file_event_filter" command specified what type of events will be written to the EDF file. It may be changed in the PARSER.INI file of the EyeLink II tracker, or may be sent over the link. The command is followed by a list of data...

  • Page 81: Edfscan

    It is easily read, and is ordered to make most data-processing tasks straightforward. Many translation options are available, specifying the file contents. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 74...

  • Page 82: Edf2Asc

    "trial1.edf" to "trial1a.asc" Edf2asc trial* translates "trial1.edf", "trial2.edf" etc. to "trial1.asc", "trial2.asc" etc. Edf2asc trial* -p asc translates "trial1.edf" etc. to "asc\trial1.asc" etc. (in "asc" subdirectory) EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 75...
  • Page 83 Gaze-position resolution (in units of pixels per visual degree) is computed by the EyeLink II tracker, and must be recorded in the EDF file as it cannot be computed. No resolution data is available for raw pupil-position data.
  • Page 84 Resolution data is not available in some EDF files, or for raw pupil-position data. A default resolution value can be set using the "-defres" option, which is EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 77...

  • Page 85: The Asc File Format

    • Event and data-description lines. Each line begins with a keyword, identifying the type of data in the rest of the line. 4.9.1 ASC File Structure EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 78...

  • Page 86: Sample Line Format

    Sample lines contain time, position, and pupil size data. Optionally, velocity and resolution data may be included. Several possible sample line formats are possible. These are listed below. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 79...
  • Page 87 X and Y position data <xpr>, <ypr> right-eye X and Y position data <ps> monocular pupil size (area or diameter) <psl> left pupil size (area or diameter) EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 80...
  • Page 88 (area or diameter) <xv>, <yv> instantaneous velocity (degrees/sec) <xvl>, <yvl> left-eye instantaneous velocity (degrees/sec) <xvr>, <yvr> right-eye instantaneous velocity (degrees/sec) <xr>, <yr> X and Y resolution (position units/degree) EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 81...

  • Page 89: Event Line Formats

    MSG <time> <message> A message line contains the text of a time stamped message. This will have been sent to the EyeLink II tracker by an application, and contains data for analysis or timestamps important events such as display changes or subject responses.
  • Page 90 All samples that are within the fixation will be listed between the SFIX and EFIX event for each eye, simplifying data analysis. 4.9.3.5 Saccades SSACC <eye> <stime> • EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 83...

  • Page 91: Data-Specification Lines

    4.9.4 Data-Specification Lines Immediately following a START line, several lines of data specifications may be present. These lines contain more extensive data than the START line about EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 84...
  • Page 92 “RATE” for the sample rate (250.00 or 500.00) o “TRACKING” for the tracking mode (P = Pupil, CR = Corneal Reflection) o “FILTER” for the filter level used (0=off, 1=standard, 2=extra) EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 85...

  • Page 93: Processing Asc Files

    DEMO.EXE, and can be used as a template for creating your own analyzers. Any program that uses the standard messages used by DEMO.EXE will work with this. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 86...
  • Page 94 EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 87...

  • Page 95: Troubleshooting

    5. Troubleshooting Here are some common and not so common problems that can be encountered with the EyeLink II system. If the suggestions provided here do not solve the issue, please contact a SR Research representative. Problem: Eye Camera Images are blank or blue •...
  • Page 96 EyeLink card and possibly the marker set to SR Research for testing and repair. This is because there are no user- serviceable parts on the EyeLink II card or on the headband. Be sure to follow the packing instructions you received with the system when repackaging the EyeLink II into it’s shipping case.

  • Page 97: System Care

    Next, gently slide your fingers along the sheath from 2 meters down the cable towards the headband, to ensure that the sheath is loose near the headband. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 90...

  • Page 98: Storage And Transportation

    Between uses, it is recommended that the EyeLink II headband be placed on a glass or foam dummy head. If the EyeLink II system is not going to be used for an extended period, you may wish to disconnect the headband and marker cables from the computer and pack these in the shipping case, as detailed below.
  • Page 99 If the EyeLink II card is also to be packaged, remove it from the computer and place it into its anti-static bag, then into its slot in the foam. Close the shipping case, checking for excessive pressure that may indicate an obstruction.

  • Page 100: Important Information

    7.1.2 Eye Illumination Safety The EyeLink II system is compliant with the IEC-825 LED safety standard as a Class 1 LED device, and incorporates an active LED current monitoring system to ensure compliance even if hardware faults occur. This circuit also shuts off power to all illuminators and markers when the EyeLink II software is not running.

  • Page 101: Limited Hardware Warranty

    EyeLink II High Speed Eye Tracker Headband and Cable– One (1) year parts and labor. EyeLink II High Speed Eye Tracker PCI Card– One (1) year parts and labor.

  • Page 102: Limited Software Warranty

    EyeLink is a registered trademark of SR Research Ltd. All other company and / or product names are trademarks of their respective manufacturers. Product design and specifications may change at any time without notice. EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 95...

  • Page 103: Appendix A: Using The Eyelink Ii Analog And Digital Output Card

    EyeLink tracker, or recorded to the EDF data file. The outputs may be controlled by out-port commands via the link, or used by the EyeLink tracker for data strobes and other functions. A digital only card (the DT335) is also available.

  • Page 104: Setting Up The Eyelink Ii Analog Card

    The port address for the C and D ports on the EyeLink analog output card are 4 and 5, EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 97...

  • Page 105: Analog Data Output Assignments

    ;; use all bits 8.3.1 Analog Data Output Assignments The EyeLink II system outputs analog voltages on 3 to 6 channels, depending on the mode of operation (monocular or binocular) and the analog card configuration. The monocular analog output configuration (set by the Set Options menu screen) should be used in most cases, as it assigns the eye being actively tracked to the first 3 channels.

  • Page 106: Analog Data Types And Ranges

    For raw data, the default range is 0.1 to 0.9, because the pupil position will never reach the edges of the eye camera image. It is possible that the scaled EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 99...

  • Page 107: Pupil Size Data

    8.5 Time base and Data Strobe The EyeLink II eye tracker samples eye position every 2 or 4 msec and outputs analog data at 250 or 500 Hz. This combination of fast sampling rate and non- EyeLink II User Manual version 2.12 (07/02/2006) © 2002-2006 SR Research Ltd. 100...

  • Page 108: Strobe Data Input

    8.5.1 Strobe Data Input The best time base method is to use the EyeLink II analog output strobe, which is assigned to digital output D7 on the analog card connection board. This...

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