Driver's arousal level estimating apparatus for vehicle and method of estimating arousal level
First Claim
1. An arousal level estimating apparatus for estimating an arousal level of a driver of a vehicle comprising:
- a power calculating means for calculating a frequency component power by applying a frequency conversion method to a lateral displacement quantity detected successively;
a first evaluation value calculating means for calculating a first evaluation value based on a sum of said frequency component power calculated by said power calculating means;
a second evaluation value calculating means for calculating a maximum value of frequency component power in a specified frequency domain including a fluctuation frequency as a second evaluation value;
an evaluation value calculating means for calculating an evaluation value from a ratio of said first evaluation value and said second evaluation value; and
a judging means for judging a driver'"'"'s arousal level based on said evaluation value.
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Abstract
A driver'"'"'s arousal level estimating apparatus for a vehicle includes a Fast Fourier Transformation (FFT) signal processing section for obtaining respective frequency component powers by applying a frequency conversion to displacement quantities successively detected of the vehicle, an evaluation value calculating section for calculating an evaluation value from a ratio of an average value of the respective calculated frequency powers and a maximum value of frequency component powers in a specified frequency domain containing a predetermined lateral fluctuation frequency characteristic of a lowered arousal level, and a judging section for judging a driver'"'"'s arousal level based on the evaluation value.
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Citations
25 Claims
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1. An arousal level estimating apparatus for estimating an arousal level of a driver of a vehicle comprising:
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a power calculating means for calculating a frequency component power by applying a frequency conversion method to a lateral displacement quantity detected successively;
a first evaluation value calculating means for calculating a first evaluation value based on a sum of said frequency component power calculated by said power calculating means;
a second evaluation value calculating means for calculating a maximum value of frequency component power in a specified frequency domain including a fluctuation frequency as a second evaluation value;
an evaluation value calculating means for calculating an evaluation value from a ratio of said first evaluation value and said second evaluation value; and
a judging means for judging a driver'"'"'s arousal level based on said evaluation value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 11, 12)
said frequency component powers are subjected to a leveling process. -
3. The apparatus according to claim 2, wherein
said leveled frequency component power is obtained by multiplying said frequency component power by a frequency raised to n power. -
4. The apparatus according to claim 3, wherein
said exponent n is a value not more than 3 and not less than 2. -
5. The apparatus according to claim 1, wherein
said first evaluation value is obtained based on said frequency component powers excluding a maximum one from said respective frequency component powers calculated by said power calculating means. -
6. The apparatus according to claim 1, wherein
said evaluation calculating means calculates said evaluation value in time sequence and said judging means increases or decreases a counter value according to said evaluation value and when said counter value reaches a judging value, judges that a warning should be raised to a driver of said vehicle. -
7. The apparatus according to claim 6, wherein
said judging means changes said counter value according to said evaluation value. -
11. The apparatus according to claim 1, wherein said power calculating means comprises a fast Fourier transformation section applying a fast Fourier transformation to calculate said frequency component power.
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12. The apparatus of claim 1, wherein said power calculating means subjects a range of said frequency component power to a leveling process defined as
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8. An arousal level estimating method, comprising:
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calculating a frequency component power by applying a frequency conversion method to a lateral displacement quantity detected successively;
calculating a first evaluation value based on a sum of said frequency component power;
calculating a maximum value of frequency component power in a specified frequency domain including a fluctuation frequency as a second evaluation value;
calculating an evaluation value from a ratio of said first evaluation value and said second evaluation value; and
judging a driver'"'"'s arousal level based on said evaluation value. - View Dependent Claims (9, 10, 13, 14, 15)
subjecting said frequency component power to a leveling process.
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15. The method according to claim 8, wherein said calculating a frequency component power comprises applying a fast Fourier transformation to calculate said frequency component power.
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16. A computer-readable medium having computer-executable instructions for performing an estimation of an arousal level of a driver of a vehicle, comprising:
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calculating a frequency component power by applying a frequency conversion method to a lateral displacement quantity detected successively;
calculating a first evaluation value based on a sum of said frequency component power;
calculating a maximum value of frequency component power in a specified frequency domain including a fluctuation frequency as a second evaluation value;
calculating an evaluation value from a ratio of said first evaluation value and said second evaluation value; and
judging a driver'"'"'s arousal level based on said evaluation value. - View Dependent Claims (17, 18, 19, 20)
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21. An arousal level estimating system for estimating an arousal level of a driver of a vehicle, comprising:
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a power calculator for calculating a frequency component power by applying a frequency conversion method to a lateral displacement quantity detected successively;
a first evaluation calculator for calculating a first evaluation value based on a sum of said frequency component power calculated by said power calculating means;
a second evaluation value calculator for calculating a maximum value of frequency component power in a specified frequency domain including a fluctuation frequency as a second evaluation value;
an evaluation value calculator for calculating an evaluation value from a ratio of said first evaluation value and said second evaluation value; and
a judging section for judging a driver'"'"'s arousal level based on said evaluation value. - View Dependent Claims (22, 23, 24, 25)
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25. The system of claim 21, wherein said judging section increases or decreases a counter value according to said evaluation value, and, when said counter value reaches a judging value, judges that a warning should be raised to a driver of said vehicle.
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Specification