A widely applicable real-time mono/binocular eye tracking system using a high frame-rate digital camera

Abstract

We have developed a new mono/binocular eye tracking system by using an IEEE1394b or USB-3.0 digital camera that provides high sensitivity, high resolution, high frame-rate and no rolling shutter distortion. Our goal is to provide a system that is friendly to researchers who conduct experiments. The system is non-invasive and inexpensive and can be used for mice, marmosets, monkeys, and humans. It has adopted infrared light to illuminate an eye (eyes). The reflected image of the infrared light on the cornea and the black image of the pupil are captured by the camera. The center of the pupil and the center of the corneal reflection are calculated and tracked over time. The movement of the head is compensated by the reflection. Since the high resolution camera has a 2048 horizontal pixels resolution, we can capture the images of both eyes simultaneously and calculate the parameters of the two eyes at each frame. The gaze position data can be read out on-line via computer network and/or DAC (digital analog converter). The adoption of the Windows 10 as the operation system makes this eye tracking system user-friendly. Because of the high frame-rate of the digital camera, the sampling rate of the system can be as high as 700 Hz and the latency less than 4 ms.