Data-Specification Lines - SR Research EyeLink Portable Duo User Manual

The start of saccades are reported with a SSACC line, which can be eliminated
with the EDF2ASC "-nse" option from the command line prompt or by enabling
"Block Start Event Output" from the EDF2ASC converter GUI preference
settings. The <eye> is "L" or "R", indicating the eye's data that produced the
event.
The end of and summary data of the saccade are reported with the ESACC line.
This reports the time of the first and last sample in the saccade, and computes
its duration in milliseconds. The X and Y eye position at the start and end of
the saccade (<sxp>, <syp>, <exp>, <eyp>) are listed. The total visual angle
covered in the saccade is reported by <ampl>, which can be divided by
(<dur>/1000) to obtain the average velocity. Peak velocity is given by <pv>.
Optionally, the eye-position angular resolution (in units per visual degree) is
given as well.
All samples that are within the saccade will be listed between the SSACC and
ESACC events for each eye, simplifying data analysis.
4.9.3.6 Blinks
SBLINK <eye> <stime>
•
EBLINK <eye> <stime> <etime> <dur>
•
Blinks (periods of data where the pupil is missing) are reported by the SBLINK
and EBLINK lines. The time of the start of the blink is indicated by the SBLINK
line, which can be eliminated with the EDF2ASC "-nse" option. The <eye> is "L"
or "R", indicating the eye's data that produced the event. The end and duration
are given in the EBLINK event.
Blinks are always embedded in saccades, caused by artificial motion as the
eyelids progressively occlude the pupil of the eye. Such artifacts are best
eliminated by labeling an SSACC...ESACC pair with one or more SBLINK events
between them as a blink, not a saccade. The data contained in the ESACC event
will be inaccurate in this case, but the <stime>, <etime>, and <dur> data will be
accurate.
It is also useful to eliminate any short (less than 100 millisecond duration)
fixations that precede or follow a blink. These may be artificial or be corrupted
by the blink.

4.9.4 Data-Specification Lines

Right before each block of recorded data, a few specification lines are written to
the EDF file to report the recording information of the trial such as mount type,
sampling rate, filtering level, pupil threshold, and pupil tracking algorithm.
RECCFG <tracking mode> <sampling rate> <file sample filter> <link sample
•
filter> <eye(s) recorded>
96 Data Files
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