WAKEFULNESS LEVEL ESTIMATION APPARATUS

• US 20090268022A1
• Filed: 04/23/2009
• Published: 10/29/2009
• Est. Priority Date: 04/23/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: OMI, Takuhiro
• Granted Patent: US 8,823,792 B2
• Time in Patent Office: Days
• US Class Current: 348/135
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

A wakefulness level estimation apparatus includes: an estimation portion that estimates a level of wakefulness of a subject person based on one of a wakefulness level estimation function, of which a variable is a wakefulness level correlation value of the subject person, and a difference between the wakefulness level correlation value of the subject person and a reference value of the wakefulness level correlation value; a stimulation detection portion that detects whether an awakening stimulation is externally applied to the subject person; and a correction portion that, when the stimulation detection portion detects that the awakening stimulation is applied to the subject person, performs a correction of one of the reference value of the wakefulness level correlation value and the wakefulness level estimation function, which is used for estimating the level of wakefulness of the subject person.

Claims

1. A wakefulness level estimation apparatus, comprising:

an estimation portion that estimates a level of wakefulness of a subject person based on one of a wakefulness level estimation function, of which a variable is a wakefulness level correlation value of the subject person, and a difference between the wakefulness level correlation value of the subject person and a reference value of the wakefulness level correlation value;

a stimulation detection portion that detects whether an awakening stimulation is externally applied to the subject person; and

a correction portion that, when the stimulation detection portion detects that the awakening stimulation is applied to the subject person, performs a correction of one of the reference value of the wakefulness level correlation value and the wakefulness level estimation function, which is used for estimating the level of wakefulness of the subject person.

2. The wakefulness level estimation apparatus according to claim 1, wherein:

the stimulation externally applied to the subject person is provided by a plurality of stimuli including a tension stimulus;

the wakefulness level correlation value includes a plurality of blinking characteristic amounts including a number of blinks; and

when the stimulation detection portion detects that the subject person is externally stimulated by the tension stimulus, the correction portion performs the correction in a manner different from a manner when the subject person is stimulated by another stimulus than the tension stimulus.

3. The wakefulness level estimation apparatus according to claim 2, wherein when the stimulation detection portion detects that the subject person is stimulated by the tension stimulus, the correction portion performs the correction without changing a value pertaining to the number of blinks, which is one of the blinking characteristic amounts.

4. The wakefulness level estimation apparatus according to claim 1, wherein the level of wakefulness of the subject person is determined based on an eye-opening degree of the subject person.

5. The wakefulness level estimation apparatus according to claim 1, wherein when the stimulation detection portion detects that the stimulation is externally applied to the subject person, the correction portion corrects the wakefulness level estimation function when the level of wakefulness of the subject person estimated based on the wakefulness level estimation function does not show that an awakening effect on the subject person is produced.

6. The wakefulness level estimation apparatus according to claim 1, wherein the wakefulness level estimation apparatus is mounted on a vehicle, and the stimulation detection portion detects that the stimulation is externally applied to the subject person when the vehicle runs in an area in which it is assumed that the awakening effect is produced by the stimulation externally applied to the subject person.

7. The awakening level estimation apparatus according to claim 6, wherein the area in which it is assumed that the awakening effect is produced by the stimulation externally applied to the subject person is an area in which a facility is provided on a road to produce the awakening effect on the subject person.

8. The awakening level estimation apparatus according to claim 6, wherein the area in which it is assumed that the awakening effect is produced by the stimulation externally applied to the subject person is an area in which the tension stimulus is applied to the subject person due to a change of road circumstances and surrounding circumstances of the vehicle.

9. The wakefulness level estimation apparatus according to claim 8, wherein:

the wakefulness level correlation value includes a plurality of blinking characteristic amounts including a number of blinks; and

when the stimulation detection portion detects that the subject person is stimulated by the tension stimulus, the correction portion performs the correction without changing a value pertaining to the number of blinks, which is one of the blinking characteristic amounts.

10. The wakefulness level estimation apparatus according to claim 6, wherein the area in which it is assumed that the awakening effect is produced by the stimulation externally applied to the subject person is an area in which a physical stimulus that produces the awakening effect is applied to the subject person.

11. A wakefulness level estimation apparatus, comprising:

an estimation portion that estimates a level of wakefulness of a subject person based on both a wakefulness level estimation function, of which a variable is a wakefulness level correlation value of the subject person, and a difference between the wakefulness level correlation value of the subject person and a reference value of the wakefulness level correlation value;

a stimulation detection portion that detects whether an awakening stimulation is externally applied to the subject person; and

a correction portion that, when the stimulation detection portion detects that the awakening stimulation is applied to the subject person, performs a correction of both the reference value of the wakefulness level correlation value and the wakefulness level estimation function, which are used for estimating the level of wakefulness of the subject person.