Optical flow may improve eye-tracking spatial resolution

DÉCIMA, A.; BARRAZA J.F.; JAÉN, M.

Marsella

Congreso; 16ta Conferencia Europea de Movimientos Oculares; 2011

 We are currently developing an eye-tracker that would allow us to measure fixational eye-movements accurately. To achieve this goal, it is essential that the instrument can guarantee high resolution in both spatial and temporal dimensions, e.g. microsaccades can be as little as 10 ms in duration and 5 minute of arc in distance. After a thorough search of the bibliography, we found that although great efforts have been made to achieve friendly, robust, remote, calibration-free eye-trackers, little has been done regarding spatial resolution (see for example [1]). Here, we propose a new method based on the Horn-Schunck [2] optical-flow algorithm to improve the spatial resolution of the eye-tracking techniques. To test its performance, we developed an optically-realistic artificial eye, which was mounted on a goniometer equipped with a 0.01 deg micrometer that allowed us to precisely control its movement, thus enabling us to measure the spatial resolution of  eye-detection techniques. We tested the results of standard edge detection algorithms (e.g. sobel, LoG, etc. ) and of the Starburst eye-detection technique [3] in order to determine the spatial resolution of these methods, and compared them with our own proposal.