Pro Spectrum User Manual v2.1 23
9 Technical Specifications
9.1 Eye tracking specifications
The characteristics of the gaze data from an eye tracker are described in terms of accuracy and pre-
cision. Accuracy indicates the angular average distance from the actual gaze point to the one meas-
ured by the eye tracker. Gaze precision indicates the spatial variation between successive samples
collected when the subject fixates at a specific point on a stimuli.
Eye-tracking technique Video-based pupil- and corneal reflection
eye tracking with dark and bright pupil illu-
mination modes.
Two cameras capture stereo images of both
eyes for robust, accurate measurement of
eye gaze and eye position in 3D space, as
well as pupil diameter.
Sampling frequency 60, 120, 150, 300, 600 or 1200 Hz (max. fre-
quency depends on hardware version)
Precision* 0.01° RMS at optimal conditions**
0.06° RMS at optimal conditions (raw signal)
Accuracy* 0.3° at optimal conditions
Binocular eye tracking Yes
Total system latency Less than 3 frames (less than 2.5 ms for
1200 Hz)
Blink recovery time One frame (immediate)
Gaze recovery time Less than 150 ms
Data Sample Output***
Timestamp
Gaze origin
Gaze point
Pupil diameter
Eye image data stream Eye image stream frequency is approx-
imately 10 Hz (one image with both eyes).
Zoomed-in eye images available in tracking
mode.
Full-frame camera images are available in
gaze recovery mode.
TTL input stream 8–bit timestamped data (256 event codes).
Event driven detection with a timestamp
accuracy of 50 µs.
Tracker and client time synchronization Integrated between the eye tracker time
domain and the client computer time domain
with an accuracy of 100 µs.
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