Towards a low cost and high speed mobile eye tracker

Abstract

Despite recent developments in eye tracking technology, mobile eye trackers (ET) are still expensive devices limited to a few hundred samples per second. High speed ETs (closer to 1 KHz) can provide improved flexibility for data filtering and more reliable event detection. To address these challenges, we present the Stroboscopic Catadioptric Eye Tracking (SCET) system, a novel approach for mobile ET based on rolling shutter cameras and stroboscopic structured infrared lighting. SCET proposes a geometric model where the cornea acts as a spherical mirror in a catadioptric system, changing the projection as it moves. Calibration methods for the geometry of the system and for the gaze estimation are presented. Instead of tracking common eye features, such as the pupil center, we track multiple glints on the cornea. By carefully adjusting the camera exposure and the lighting period, we show how one image frame can be divided into several bands to increase the temporal resolution of the gaze estimates. We assess the model in a simulated environment and also describe a prototype implementation that demonstrates the feasibility of SCET, which we envision as a step further in the direction of a mobile, robust, affordable, and high-speed eye tracker.