Bright-pupil Artificial Eye with High-speed Motion

Summary

Eye trackers are used in a variety of situations to understand human behavior and conditions based on eye gaze, and artificial eyes as well as humans play an important role in evaluating the accuracy and precision of eye trackers. Generally, eye trackers use near-infrared light and a camera to measure the eyeball. If the near-infrared light source is close to the optical axis of the camera, the pupil is observed as a bright pupil; if it is far away, the pupil is observed as a dark pupil. Microsaccades, a type of eye movement, are expected to lead to neurophysiological and psychophysical discoveries, but the extremely small and rapid movements of microsaccades require head fixation with a chinrest. The development of measurement devices and detection algorithms for the detection of microsaccades in free head movement situations requires the development of artificial eyes that can reproduce quick microsaccades.

In this study, we propose an artificial eye with a bright pupil that enables microsaccadic high-speed motion (Fig. 1). The plano-convex lens, which imitates corneal reflection, is processed with a sandy surface and retroreflective material is placed on the back of the lens to have an optical design that reproduces bright pupils while maintaining light weight for high-speed motion (Fig. 2, 3). Galvano motors rotate the miniature artificial eye to reproduce microsaccadic high-speed motion (Fig. 4). The bright pupil feature facilitates high-speed tracking of head movement, and by reproducing quantitative micro-rotation by the motor, it is expected to lead to the development of an eye movement measurement system that allows free head movement, thereby promoting applications in the medical and life science.

This content is based on the results of joint research with NEC Corporation.

Fig. 1 Concept.	Fig. 2 Optical design.
Fig. 3 Artificial eye.	Fig. 4 Microsaccadic motion.

Reference

1. Tomohiro Sueishi, Soichiro Matsumura, Shoji Yachida, and Masatoshi Ishikawa: Optical and Control Design of Bright-Pupil Microsaccadic Artificial Eye, 2022 IEEE/SICE International Symposium on System Integration (SII2022) (Online, 2022.1.11)/Proceedings, pp.760-765