The feasibility of a system to measure blink rate, percentage eyelid closure, blink amplitude, and blink duration from real-time video analysis to detect operator fatigue and produce countermeasures will be evaluated. The system produces an alarm when the onset of fatigue is detected (or the eyes remain closed longer than a selected interval). An active pixel camera will be used to acquire video images of the operator's eyes. Active pixel cameras are produced by a relatively inexpensive CMOS fabrication technique that can produce both analog to digital conversion circuitry on the same chip, thus the active pixel camera can produce digital video that is usable directly by a computer with no intermediate video boards, etc. A compact computer system will process the video images using specially designed algorithms to detect and quantify features of the eye in real-time. An inexpensive and non-invasive fatigue monitoring system would have broad commercial applications in aviation and ground transportation. The interruption of the circadian cycle in space flight and long distance aviation, and the continuous state of alertness required during certain tasks make alertness and fatigue monitoring especially important in these situations.