Abstract
A drowsy driving warning system has been developed that uses image processing technology to calculate the blink rate of the driver's eyes. One issue that had to be addressed in developing this system was to ensure sufficient adaptability to ambient light changes in the passenger compartment during driving. The aim of the present work was to develop an image processing algorithm capable of coping with such ambient light changes. The results of drowsy driving detection tests conducted with an actual vehicle have confirmed the effectiveness of the detection algorithm.