eye tracking systems by Arrington Research, Inc.

Head Fixed Eye Tracking System Specifications

Tracking Method
Infrared video. Bright pupil or dark pupil. Monocular or binocular options.
Software PC
Measurement principle The user can select between three methods: Pupil only, corneal reflection only, or both together for greater tolerance to head movements.
Accuracy* Approximately 0.25° - 1.0° visual arc
Spatial resolution* Approximately 0.15° visual arc
Temporal resolution selectable by the user between 60 Hz and 30 Hz.
Allowable head movement Small movements allowed. Subject's pupil and corneal reflection must remain within the camera image.
Visual range Horizontal: +/- 44° of visual arc
Vertical: +/- 20 ° of visual arc
Pupil size resolution Measures pupil height and width to better than 0.03 mm instantaneous (no averaging).
Calibration ViewPoint starts in a roughly calibrated state that is adequate for determining screen quadrants or other relative movement measurement such as objective preference-of-looking tasks.

For accurate position of gaze, calibration is required only once per subject. New subject setup time between 1-5 minutes. Calibration settings can be stored and reused each time a subject returns.

Easy Slip Correction feature and re-presentation of stray calibration points.

Auto threshold The program scans over the video image for the pupil and / or for the corneal reflection. The luminance threshold for discriminating these can be adjusted. The auto threshold feature provides good threshold levels automatically. Little or no manual adjustment required.
Blink suppression Automatic blink detection and suppression.
Data recorded Eye data: X, Y position of gaze, pupil height and width, ocular torsion, delta time, total time, and regions of interest (ROI).

Asynchronous records include: State transition markers, key presses, data from other programs.

Data is stored in ASCII files.

Real-time communication Same computer:
Software Developers Kit (SDK) supplies everything you need for seamless interface between ViewPoint and your program. This includes: DLL with shared memory, .h and .lib files plus sample source code written in C Language.

Serial port:
Sends eye data packets and asynchronous packets equivalent to information in ASCII data files at rates of up to 56K.
Receive real time data from other programs and store it asynchronously into data files.

AnalogOut option:
Selectable unipolar or bipolar voltage ranges: +/- 10, 5, 2.5
Selectable data items: position of gaze (x,y), pupil (h,w), velocity (dx,dy), and raw pupil, glint or vector data. TTL capabilities. 2, 4 or 8 channel options.

TTL in/out option:
Eight TTL input channels are interfaced to place marker codes into the ViewPoint data file. Eight TTL output channels that indicate when the position of gaze is inside ViewPoint region of interest areas ROI-0 to ROI-7.

full real-time synchronization across machines via the ethernet.

Real-time display Gaze point history, gaze trace, fixation duration, pupil size and ROIs, can be graphically displayed over stimulus image. Visible to the user and / or the subject.

Real-time pen plots of X and Y position of gaze, velocity, ocular torsion, pupil width and pupil aspect ratio.

Stimulus Presentation Pictures and movies can be displayed in full stimulus windows or in user specified ROIs. Auditory cues can be integrated. Gaze contingent stimulus presentation via state logic.
System requirements:

OS: Windows 7, Windows 8, Windows 8.1, Windows10

OEM Support The ViewPoint software can be configured to accommodate a wide variety of OEM hardware. Resolution and accuracy will then depend on the OEM camera and hardware configuration.
*Arrington Research takes performance measurements during actual use with human subjects. Better results than stated are possible under artificial conditions but are almost never achieved in reality. Performance terms used are defined below:
Accuracy: The expected difference in degrees of visual angle between true eye position and mean computed eye position during a fixation.
Spatial Resolution: The smallest change in eye position that can be measured.

Specifications and design are subject to change without notice.