The study of remote saccade sensing system based on retroreflective feature of the retina

We present a new method for detecting rapid eye movements called a saccade without constraining the head, based on the fast, robust pupil detection technique [1][2]. The technique uses two infrared light sources synchronized with the camera’s frame rate. The two light sources generate an image with a bright pupil and an image with a dark pupil. By taking a subtraction between the two images, we can carve out the positions of the pupils. From the series of the captured images, the change of gaze direction is measured as the displacement of the pupils' positions within the image. Measuring the displacement with a line scanning camera, which can take one line image with high frequency (more than 1kHz), the saccade can be detected. In this study we investigated the feasibility of this method by clarifying the retroreflective feature of the pupil and composed prototype system to detect saccadic eye movements.