Patent ID: 8045766

Claim:
A sleepiness determination device comprising: facial expression information obtaining means for obtaining at least two of facial expression information elements (A) to (K) associated with a facial image including: (A) a distance between left and right corners of a mouth; (B) a distance between an eyebrow and eye; (C) a tilt angle of a head; (D) a distance between the midpoint between inner corners of eyebrows and the midpoint between inner corners of eyes; (E) a distance between inner corners of eyebrows; (F) a distance between the midpoint between outer corners of a lower nose and the midpoint between inner corners of eyes; (G) a distance between the midpoint between corners of a mouth and the midpoint between inner corners of eyes; (H) a distance between a lower edge of a lower lip and the midpoint between inner corners of eyes; (I) a distance between upper and lower eyelids; (J) a distance between outer corners of a lower nose; and (K) a distance between an upper edge of an upper lip and the midpoint between inner corners of eyes; and sleepiness determination means for: determining a respective indication of sleepiness for each of the at least two facial expression information elements; and determining a level of sleepiness based on the respective indication of sleepiness for the each of the at least two facial expression information elements, wherein the sleepiness determination means obtains the (C) tilt angle of the head in addition to the at least two of the facial expression information elements (A) to (K) other than the (C) tilt angle of the head, the at least two of the facial expression information elements (A) to (K) including the (A) distance between the left and right corners of the mouth and the (B) distance between the eyebrow and the eye; a first condition includes that sleepiness is determined to be present based on the (A) distance between left and right corners of a mouth, a second condition includes that sleepiness is determined to be present based on the distance (B) between an eyebrow and eye and based on the first condition, and a third condition includes that sleepiness is determined to be present based on the (C) tilt angle of a head and based on the first and second conditions, and the level of sleepiness is determined as slight sleepiness when the only first condition is satisfied, the level of sleepiness is determined as moderate sleepiness higher than the slight sleepiness when only the second condition is satisfied and the level of sleepiness is determined as strong sleepiness higher than the moderate sleepiness when only the third condition is satisfied, and the level of sleepiness is determined as no sleepiness when none of the conditions are satisfied.