US Patent 7821409 Drowsiness alarm apparatus and program

A drowsiness alarm apparatus and a program for decreasing the possibility of incorrectly issuing an alarm due to an expressed emotion is provided. A wakefulness degree calculation apparatus performs a wakeful face feature collection process to collect a wakefulness degree criterion and an average representative feature distance. A doze alarm process collects a characteristic opening degree value and a characteristic feature distance. The wakefulness degree criterion is compared with the characteristic opening degree value to estimate a wakefulness degree. The average representative feature distance is compared with the characteristic feature distance to determine whether the face of the driver expresses a specific emotion. If the face expresses the emotion, alarm output is inhibited. When the face does not express the emotion, an alarm is output in accordance with the degree of decreased wakefulness so as to provide an increased alarm degree for the driver if necessary.