US 8,045,766 B2Granted

Device, program, and method for determining sleepiness

AssigneeDenso Corporation

InventorsKenji Ishida, Kahori Uchiyama, Teiyuu Kimura, Noriyuki Ozaki

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Abstract

A sleep prevention system captures a facial image of a driver, determines a sleepiness level from the facial image and operates warning devices including neck air conditioner, seatbelt vibrator, and brake controller if necessary based on the sleepiness determination. A sleepiness determination device determines sleepiness from facial expression information such as distances between corners of a mouth, distance between an eyebrow and eye, tilt angle of a head, and other facial feature distances. The facial distances are calculated from captured images and from reference information gather during wakefulness. The sleepiness degree is determined based on the determination results including combinations thereof.

Claims9

Dependent claims

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.

18 more elements

A sleepiness determination device comprising:

facial expression information obtaining means for obtaining at least two of facial expression information elements 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, and
(C) a tilt angle of a head;
and
sleepiness determination means for determining a degree of sleepiness for each of the facial expression information elements by using three conditions (a), (b) and (c), by which presence of sleepiness is determined based on the facial expression information elements (A), (B) and (C), respectively, wherein
the sleepiness determination means determines the degree of sleepiness to be
strong sleepiness when the condition (c) is satisfied,
moderate sleepiness, which is lower than the strong sleepiness, when the condition (b) is satisfied but the condition (c) is not satisfied,
slight sleepiness, which is lower than the moderate sleepiness, when the condition (a) is satisfied but the conditions (b) and (c) are not satisfied, and
no sleepiness when none of the conditions (a), (b) and (c) is satisfied.

8 more elements

Dependencies are inferred from the claim text.