Abstract: A method and apparatus for measuring drowsiness particularly in vehicle operators measures the amplitude to velocity ratio for eyelids closing and opening during blinking as well as measuring duration of opening and closing. The average values for the amplitude to velocity ratios for opening and closing are weighted and added to give a drowsiness measure that is compared to a scale of drowsiness based on data collected from alert and drowsy subjects. Other eye movements can be used in the weighted algorithm. The scale of drowsiness predicts the onset of drowsiness levels that render an operator unfit to continue.

Abstract: An alertness monitoring system includes: means to measure velocity and amplitude of eyelid and eye movement; and storage means to continuously record the measurements. A data processor calculates the blink amplitude to velocity ratio and/or the saccade amplitude to velocity ratio and compares the measurements against a predetermined scale. The scale is derived from averaged measurements of the eye and eyelid movement parameters for a sample population measured against predetermined incremental blood alcohol levels. The output of the system can include a display for showing the alertness measurement based on the scale, or an alarm means triggered by the scale reading reaching a predetermined limit based an the blood alcohol level scale.