Integrated Gaze-Tracking for KINARM Labs™
BKIN’s Design Philosophy:
Our goal from the beginning was to add gaze-tracking to the KINARM Lab to enable maximum flexibility for our KINARM users. By integrating gaze-tracking directly into the KINARM Lab, we knew our customers would benefit from an exponential increase in experimental possibilities, without the headache of having to customize and coordinate multiple hardware solutions. A head-free solution was the natural choice because it simplifies the experimental set-up, particularly for KINARM users conducting clinical research. Further, head-free tracking is easily accommodated in the KINARM Virtual Reality System where space is limited, allowing nothing to interfere with the head.
The KINARM Gaze-Tracker has been designed based on extensive research into gaze-tracking solutions. After exhaustive testing, we determined that SR Research’s fiber-optic based EyeLink 1000 Remote provided the best basis for a solution for many reasons. Not only is it the best head-free solution (highest accuracy, speed, etc) but the EyeLink 1000 is a robust and flexible tracker with a significant customer base and a great track record of successful research use.
BKIN has significantly customized the EyeLink 1000 Remote to work effectively in a KINARM Lab. A number of challenges have been overcome, including using the gaze tracker with a horizontal image plane (rather than vertical); locating the eye tracker in a Virtual Reality environment such that it is compatible with a KINARM robot; developing custom hot mirrors the size of a 47” TV; and integrating calibration and data collection with our KINARM control software: Dexterit-E™.
Sampling Rate: The EyeLink 1000 Remote from SR Research operates at a very fast 500 Hz.
Subject Setup: The EyeLink 1000 Remote requires a quick 13 point calibration, flexible enough for patient use.
Resolution: Per SR Research, for Remote/Head Free, the EyeLink 1000 provides a resolution of 0.05°RMS; saccade resolution of 0.25°.
Recovery from Loss of Tracking: A target sticker on the subject's head provides eye distance and relative position information for fast recovery when tracking is interrupted.
Accuracy: With minimal head movement, BKIN has measured a mean accuracy under ~0.5° in the KINARM Lab workspace. With head motion, BKIN has observed some correlated inaccuracy up to ~1° for extreme head motion.
Workspace Area: The range over which gaze-tracking is possible is roughly ellipsoid: ~55° in the horizontal and ~40° in the vertical. In the horizontal plane of the KINARM Virtual Reality System, these gaze angle ranges correspond to ~50 cm x ~30 cm. This range does not cover the entire Virtual Reality workspace in a KINARM Lab, which is a much larger workspace. The gaze tracking is centered in the middle of the KINARM Lab workspace so that the range is optimized for use with the KINARM.
BKIN provides full technical support on KINARM Gaze Trackers.
BKIN does not support or warrant that the KINARM Gaze Tracker or any component thereof can be used independent of the KINARM Lab. Given that the hardware is tightly integrated and modified from its original form, disassembly of a KINARM Gaze Tracker for use outside of a KINARM Lab voids any support or warranty provided by BKIN.
EyeLink is a trademark of SR Research Ltd, Mississauga, Canada.
BKIN has patents pending on the KINARM Gaze-Tracker integrated with KINARM Labs.