An EyeLink Portable Duo Tutorial: Running an Experiment
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2016-2017 SR Research Ltd.
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When the last calibration target has been presented, the calibration will be
evaluated. At the bottom of the Calibrate screen, each eye's calibration is
graded and displayed as follows:
GOOD: No obvious problems found with the data
FAILED: Could not use data, calibration must be repeated
The user must still check the accuracy of the calibration: only serious problems
can be detected automatically. In particular, please examine the pattern formed
by the eye-position cursors (arrays of crosses) for misplaced or missing
fixations. A good calibration is indicated by a regular pattern of parallel
horizontal and vertical lines formed by the calibration fixation crosses. If the
calibration was successful, you may press the “Accept” button or the ENTER
key to accept the calibration results. Pressing the “Restart” button or the ‘ESC’
key will restart the calibration. Pressing ‘ESC’ twice exits to the Setup screen.
So if you want to keep the current calibration, never press the ESC key at the
end of the calibration where the calibration grid is displayed. Doing so will
discard the current calibration and thus revert to the existing cached
calibration.
In all screens, the Host Application reports any unusual status for the pupil,
corneal-reflection, and target sticker (the latter only in the Remote Mode)
signals near the thumbnail eye and target images if there are any lapses in data
collection. Should any of the indicators be displayed and the participant is
looking at the screen and not blinking, there is a problem with the setup that
must be addressed to prevent data loss.
Indicator
Status of Pupil
SIZE
Pupil is too large or too small
PUPIL MISSING
Pupil is missing
BOUNDS
Pupil is missing or the gaze data is not valid
The pupil status error message “SIZE”, highlighted in yellow, indicates that the
size of the pupil is too large or too small. For the Remote Mode, the pupil “SIZE”
warning typically suggests that the pupil size is too small because of the
ambient lighting or the eye tracker is placed too far away from the participant.
The pupil status error message “MISSING” highlighted in red, indicates that the
pupil is missing from the camera view. This could be that the participant is
blinking. It could also be that there is a problem with camera setup. Please
adjust as needed.
Indicator
Status of Corneal Reflection
MISSING
Corneal Reflection is missing
BOUNDS
Corneal Reflection is missing or the gaze data is not valid
