Driver's arousal level estimating apparatus for vehicle and method of estimating arousal level

• US 6,335,689 B1
• Filed: 10/13/1999
• Issued: 01/01/2002
• Est. Priority Date: 10/16/1998
• Status: Expired due to Fees

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Mine, Atsushi
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US09/416,793
• Time in Patent Office: 811 Days
• Field of Search: 340/575, 340/576, 180/272
• US Class Current: 340/576
• CPC Class Codes: B60K 28/06 responsive to incapacity of driver
• CPC Class Codes: B60K 28/066 actuating a signalling device B60K28/063 takes precedence
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

A lateral displacement of a vehicle is detected consecutively and the displacement is subjected to a frequency conversion to obtain a frequency component power. Then, a first integral of the frequency component power is obtained with respect to frequency of a low frequency domain and a second integral of the power is obtained with respect to frequency of a high frequency domain. An evaluation value is calculated from thus obtained first and second integrals and a driver'"'"'s arousal level is judged based on the evaluation value.

Claims

1. An arousal level estimating apparatus of a vehicle for estimating an arousal level of a driver, comprising:

vehicular behavior detecting means for continuously detecting behavior of said vehicle;

a power calculating means for calculating a frequency component power by applying a frequency conversion to said vehicular behavior;

a low frequency domain establishing means for establishing a low frequency domain lower than a reference frequency;

a high frequency domain establishing means for establishing a high frequency domain higher than said reference frequency;

an evaluation value calculating means for obtaining a first integral of said frequency component power in said low frequency domain, for obtaining a second integral of said frequency component power in said high frequency domain, and for calculating an evaluation value based on said first integral and said second integral; and

a judging means for judging an arousal level of said driver based on said evaluation value.

2. The apparatus according to claim 1, wherein said vehicular behavior is a lateral displacement of said vehicle.

3. The apparatus according to claim 1, wherein

said frequency component power is a frequency component power subjected to a leveling process.

4. The apparatus according to claim 3, wherein said frequency component power subjected to a leveling process is equal to said frequency component power multiplied by a nth power of a frequency.

5. The apparatus according to claim 4, wherein said exponent n is a value larger than 2.0 and smaller than 3.0.

6. The apparatus according to claim 1, wherein

said evaluation value calculating means is a means for obtaining a third integral of a reference line in said low frequency domain, for obtaining a fourth integral of said reference line in said high frequency domain, and for calculating an evaluation value from a difference between said first integral and said third integral and a difference between said second integral and fourth integral and said reference line is established such that said reference line cancels a change based on a characteristic of said frequency component power.

7. The apparatus according to claim 1, wherein

said low frequency domain is a domain below said reference frequency and above a first frequency from which a very low frequency produced when said vehicle travels on a curved road is deleted.

8. The apparatus according to claim 1, wherein

said high frequency domain is a domain above said reference frequency and below a second frequency which is obtained by adding a difference between said reference frequency and said first frequency to said reference frequency.

9. The apparatus according to claim 1, wherein

said evaluation value is a ratio of said second integral to said first integral.

10. The apparatus according to claim 1, wherein

said reference frequency is established at a larger value with an increase of a vehicle speed.

11. The apparatus according to claim 1, wherein

said judging means is a means for judging said arousal level by comparing said evaluation value with a second threshold value.

12. The apparatus according to claim 11, wherein

said second threshold value is variable in accordance with a vehicle speed.

13. The apparatus according to claim 11, wherein said second threshold value is established according to an initial evaluation value and said initial evaluation value is calculated based on said vehicular behavior acquired within a predetermined sampling period.

14. The apparatus according to claim 13, wherein

said predetermined sampling period is a period starting when a specified time elapses from a time to start judging a driver'"'"'s arousal level.

15. An arousal level estimating apparatus of a vehicle for estimating an arousal level of a driver, comprising:

vehicular behavior detecting means for continuously detecting vehicular behavior of said vehicle;

a power calculating means for calculating a frequency component power by applying a frequency conversion to said vehicular behavior;

a low frequency domain establishing means for establishing a low frequency domain lower than a reference frequency; and

a high frequency domain establishing means for establishing a high frequency domain higher than said reference frequency;

means for forming a ratio of the integrals of the frequency component power with respect to frequency in the low and the high frequency domains; and

a judging means for judging that an arousal level of said driver has declined when said frequency component power exceeds a first threshold value in said low frequency domain; and

wherein said judging means judges the arousal level based on said ratio.

16. The apparatus according to claim 15, wherein said vehicular behavior includes at least a lateral displacement of said vehicle.

17. An arousal level estimating apparatus of a vehicle for estimating an arousal level of a driver, comprising:

vehicular behavior detecting means for continuously detecting vehicular behavior of said vehicle;

a power calculating means for calculating a frequency component power by applying a frequency conversion to said vehicular behavior;

a low frequency domain establishing means for establishing a low frequency domain lower than a reference frequency; and

a judging means for judging that an arousal level of said driver has declined when said frequency component power exceeds a first threshold value in said low frequency domain; and

wherein said low frequency domain is a domain below said reference frequency and above a first frequency from which a very low frequency produced when said vehicle travels on a curved road is deleted.

18. An arousal level estimating apparatus of a vehicle for estimating an arousal level of a driver, comprising:

vehicular behavior detecting means for continuously detecting vehicular behavior of said vehicle;

a power calculating means for calculating a frequency component power by applying a frequency conversion to said vehicular behavior;

a low frequency domain establishing means for establishing a low frequency domain lower than a reference frequency; and

a judging means for judging that an arousal level of said driver has declined when said frequency component power exceeds a first threshold value in said low frequency domain; and

wherein said reference frequency is established at a larger value with an increase of a vehicle speed.

19. An arousal level estimating method of a vehicle for estimating an arousal level of a driver, comprising the steps of:

continuously detecting behavior of said vehicle;

calculating a frequency component power by applying a frequency conversion to said vehicular behavior;

establishing a low frequency domain lower than a reference frequency;

establishing a high frequency domain higher than said reference frequency;

obtaining a first integral of said frequency component power in said low frequency domain, obtaining a second integral of said frequency component power in said high frequency domain, and calculating an evaluation value based on said first integral and said second integral; and

judging an arousal level of said driver based on said evaluation value.