User manual

An EyeLink 1000 Tutorial: Running an Experiment

• Always ask the subject to look at the four corners of the display after

performing the camera setup. Watch for the warning signals on the tracker

screen to make sure that the pupil and CR signal is not lost when the subject

is doing so.

• Subjects who have never been calibrated before require some practice in

stably fixating the calibration targets. Try to perform at least two calibrations

per subject before beginning to collect data.

• Encourage subjects to sit still! A subject that doesn't sit still probably is not

paying proper attention to the experimental task.

• When writing your own applications, try to match the background color of

the screen during calibration and validation to that of the test displays.

Changes in pupil size caused by large brightness differences can degrade the

system accuracy.

• Always check for the pattern of the calibration grid. For a 9-point calibration,

the fixation crosses should form three parallel horizontal (or close-to-

horizontal) lines and three parallel vertical (or close-to-vertical) lines. Redo

calibration or camera setup if you are not seeing this.

3.10 Recording Gaze Position

After the system is set up and calibrated, we can monitor gaze position in real

time, and record it for later analysis or viewing. Pressing the “Output” button or

the ‘O’ key from the Camera Setup screen will display the Output menu, where

EyeLink Data Files (*.EDF) can be opened and closed, and analog output (if

installed) can be controlled. TRACK.EXE automatically opens a data file

‘DATA.EDF’, but you can change this by opening a new file in this menu.

Pressing ↵ (ENTER) or ‘O’ again will enter Output mode, and start display of

gaze position and data recording.

In this session, we assume the TRACK application is running on the Display

PC. When TRACK senses that the Host PC has entered Output mode, it sets up

a recording session under its own control.

On the Display PC, it displays a page of text or a target grid on its own screen

for the subject to read, alternating between recording sessions. The Host PC

screen will show the pattern of boxes that corresponds to each letter or word on

the subject’s display. This serves as a reference for the gaze-position cursor

displayed by the EyeLink 1000 during recording, allowing the operator to see

where the subject is looking and detect problems with eye-tracking errors or of