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Data Files
©
2013-2017 SR Research Ltd.
Note that the position and velocity data recorded in the ENDSACC event is not
valid. All data between the STARTSACC and ENDSACC events 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.
Fixation 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 1000 Plus
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 is 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
HTARGET
head-referenced eye position data
target distance and X/Y position (EyeLink Remote only)
PUPIL
raw pupil coordinates
AREA
pupil size data (diameter or area)
BUTTON
buttons 1-8 state and change flags
STATUS
warning and error flags
INPUT
input port data lines
The default data is:
file_sample_data =
LEFT,RIGHT,GAZE,GAZERES,PUPIL,HREF,AREA,HTARGET,STATUS,INPUT
Usually, data for both eyes is enabled, and the menus in the EyeLink 1000 Plus
tracker are used to set which eye is actually tracked. Recording of gaze and
pupil area is essential for most work, and resolution is important if velocity is to
be computed later. Recording of HREF data is optional.