Sapien Systems - Technology:Eye Tracking

Technology Development

User Monitoring

Sapien Systems is working under a U.S. Navy Space and Naval Warfare Systems (SPAWAR) contract to develop non-invasive eye movement monitoring systems. Eye movements are highly preprogrammed activities of the brain. The vast majority of eye movements are voluntarily driven. They are particularly sensitive to changes in mental states such as fatigue and drug intoxication. Sapien Systems has developed a system with a micro video-camera and optics that are integrated into part of the brim of a baseball cap. The video-camera captures a high-resolution video image of the eye that is analyzed in real-time. The computer analysis can determine the frequency and duration of eye blinks as well as the frequency and duration of changes in gaze direction. The goal of this project is to use this technology to be able to monitor the cognitive state of the user. Such states as fatigue and increased workload show changes related to eye movement behavior (see related research). With a human testing program, conditions such as stress or motion sickness are potentially measurable through eye movements.

This project is part of a larger program called "Multi-Modal Watch Station"(MMWS). The MMWS program is intended to develop workstations for US Navy crews that will allow surveillance and interaction with multiple computer monitored systems. In the Sapien Systems component of the project, two major items are being developed:

Eye-tracking hardware and software platform that is PC system based. The software platform readily allows integration of eye-tracking data into various software items, including behavior monitors and computer interaction and control technologies.
A "lookup" display that has integrated eye-tracking and a visual display that is part of the brim of a baseball cap. To increase the amount of "real-estate" of computer screens that the watch station operator has available, the small LCD screen based system is mounted so that the user can look up and see more information.

Supporting Research
Eye movement monitoring for User State. Our own life experience readily identifies eye movement and blink related activity that is related to fatigue and reduced alertness. Van Orden et al.[1] reviewed the literature of eye movement related activities and noted studies showing blink amplitude and rate [2] and blink duration and rate [3] were related to time on task and thus fatigue. The study by Van Orden [1] showed that blink frequency, fixation frequency and pupil diameter in a multi-variate analysis were well correlated with workload. The same group [4] also found that eye movement activity, specifically blink rate and duration, fixation activity and pupil diameter were also related to reduced performance when subjects were fatigued.

Van Orden, K.F., et al., Eye Activity Correlates of workload during a visuospatial memory task. 2000.
Morris, T.L. and J.C. Miller, Electrooculographic and performance indices of fatigue during simulated flight. Biol Psychol, 1996. 42(3): p. 343-60.
Stern, J.A., D. Boyer, and D. Schroeder, Blink rate: a possible measure of fatigue. Human Factors, 1994. 36(2): p. 285-97.
Van Orden, K.F., T.-P. Jung, and S. Makeig, Combined eye activity measures accurately estimate changes in sustained visual task performance, 2000.