Setting File Contents; Sample Data - SR Research EyeLink Portable Duo User Manual

or severely distorted by eyelid occlusion. Only the time of the start and end of
the blink are recorded.
Blinks are always preceded and followed by partial occlusion of the pupil,
causing artificial changes in pupil position. These are sensed by the EyeLink
parser, and marked as saccades. The sequence of events produced is always:
STARTSACC
•
STARTBLINK
•
ENDBLINK
•
ENDSACC
•
Note that the position and velocity data recorded in the ENDSACC event
following a blink are not valid. All data between the STARTSACC and ENDSACC
events in a blink-containing saccade should be discarded. The duration of the
blink may be computed by either the duration of the missing pupil between the
STARTBLINK and ENDBLINK events, or the difference between the ENDSACC
and STARTSACC events in the sequence.
Fixations immediately preceding and following blinks should be examined
carefully, as they may have been truncated or produced by the blink process.
Discarding fixations shorter than 100 ms proceeding or following blinks will
eliminate most artifacts.
4.6

Setting File Contents

The data recorded in samples and events may be set in the EyeLink
configuration file DATA.INI, and maybe overwritten by the settings in
LASTRUN.INI and FINAL.INI. As a result, it is preferred to send those
commands to the tracker across the link, via the API eyecmd_printf(). Similar
commands exist for samples and events sent over the link for real-time
applications.

4.6.1 Sample Data

The sample data written to the EDF file are controlled by the "file_sample_data"
command, which is followed by a list of data types to include. A single keyword
is included for each type:
Keyword Data Type
LEFT, RIGHT Sets the intended tracking eye (usually include both LEFT and...
RIGHT)
GAZE includes screen gaze position data
GAZERES includes units-per-degree screen resolution at point of gaze
HREF head-referenced eye position data
HTARGET target distance and X/Y position (EyeLink Remote only)
PUPIL raw pupil coordinates
AREA pupil size data (diameter or area)
86 Data Files
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