Human alertness monitored

摘要

Although machine monitoring ultimately tests for an expected breakdown, proactive monitoring of personnel who operate a machine is also essential for some systems, particularly those which are repetitive. Detecting drowsiness, and a momentary loss of consciousness, is a key aspect of this type of monitoring. The various features which indicate the onset of drowsiness include the nodding of the head, drooping of eyelids, blink duration and eye-survey speed (saccadic eye movements). Saccadic movement should occur involuntarily almost four times a second even when focused on one object. Obviously there are slight variations in acceptable times for these and so an approved range needs to be determined first.