Sleepiness level detection device
First Claim
1. A sleepiness level detection device comprising:
- means for detecting a heartbeat signal of a test subject;
calculation means for performing frequency analysis on the heartbeat signal and calculating a spectrum signal that indicates the distribution of frequency components included in the heartbeat signal; and
evaluation means for settling a band having a lower frequency than a conscious-state peak frequency as a sleepiness level index band for indicating a sleepiness level, in the spectrum signal, with respect to the conscious-state peak frequency in a conscious state of the test subject, and evaluating the sleepiness level of the test subject, on basis of strength of the spectrum signal in the sleepiness level index band;
whereinthe evaluation means evaluates the sleepiness level of the test subject when the test subject operates predetermined equipment, and the peak frequency of the spectrum signal, at a time after a predetermined time has elapsed since the fully awake test subject began operating the predetermined equipment, is set as the conscious-state peak frequency.
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Accused Products
Abstract
A sleepiness level detection device detects a heartbeat signal when a time equal to or longer than T1 and equal to or shorter than T2 has elapsed since the start of driving. The heartbeat signal is subjected to FFT processing to obtain a spectrum signal. By use of a peak frequency of the spectrum signal, a driver conscious-state peak frequency is estimated. A consciousness level index band α is set with respect to the conscious-state peak frequency. A sleepiness level index band β is set with respect to a frequency, which is calculated by multiplying the conscious-state peak frequency by a predetermined ratio (65 to 90%). A sleepiness level evaluation parameter Sp (=βp/(αp+βp)) for indicating the sleepiness level of the driver is calculated with the use of the strength αp and βp of spectrum signals.
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Citations
10 Claims
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1. A sleepiness level detection device comprising:
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means for detecting a heartbeat signal of a test subject; calculation means for performing frequency analysis on the heartbeat signal and calculating a spectrum signal that indicates the distribution of frequency components included in the heartbeat signal; and evaluation means for settling a band having a lower frequency than a conscious-state peak frequency as a sleepiness level index band for indicating a sleepiness level, in the spectrum signal, with respect to the conscious-state peak frequency in a conscious state of the test subject, and evaluating the sleepiness level of the test subject, on basis of strength of the spectrum signal in the sleepiness level index band;
whereinthe evaluation means evaluates the sleepiness level of the test subject when the test subject operates predetermined equipment, and the peak frequency of the spectrum signal, at a time after a predetermined time has elapsed since the fully awake test subject began operating the predetermined equipment, is set as the conscious-state peak frequency. - View Dependent Claims (2, 3, 4)
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5. A sleepiness level detection device comprising:
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means for detecting a heartbeat signal of a test subject; calculation means for performing frequency analysis on the heartbeat signal and calculating a spectrum signal that indicates the distribution of frequency components included in the heartbeat signal; and evaluation means for settling a band having a lower frequency than a conscious-state peak frequency as a sleepiness level index band for indicating a sleepiness level, in the spectrum signal, with respect to the conscious-state peak frequency in a conscious state of the test subject, and evaluating the sleepiness level of the test subject, on basis of strength of the spectrum signal in the sleepiness level index band;
whereinthe evaluation means calculates the conscious-state peak frequency is by averaging peak frequencies of a plurality of spectrum signals that are calculated for a predetermined detection time, from a point in time after a predetermined time has elapsed since the test subject began operating predetermined equipment.
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6. A sleepiness level detection device comprising:
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means for detecting a heartbeat signal of a test subject; calculation means for performing frequency analysis on the heartbeat signal and calculating a spectrum signal that indicates the distribution of frequency components included in the heartbeat signal; and evaluation means for settling a band having a lower frequency than a conscious-state peak frequency as a sleepiness level index band for indicating a sleepiness level, in the spectrum signal, with respect to the conscious-state peak frequency in a conscious state of the test subject, and evaluating the sleepiness level of the test subject, on basis of strength of the spectrum signal in the sleepiness level index band;
whereinthe evaluation means sets a band including the conscious-state peak frequency as a consciousness level index band, and evaluates the sleepiness level of the test subject by using strength of the spectrum signals in the consciousness level index band and the sleepiness level index band. - View Dependent Claims (7, 8, 9)
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10. A sleepiness level detection device comprising:
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means for detecting a heartbeat signal of a test subject; calculation means for performing frequency analysis on the heartbeat signal and calculating a spectrum signal that indicates the distribution of frequency components included in the heartbeat signal; and evaluation means for settling a band having a lower frequency than a conscious-state peak frequency as a sleepiness level index band for indicating a sleepiness level, in the spectrum signal, with respect to the conscious-state peak frequency in a conscious state of the test subject, and evaluating the sleepiness level of the test subject, on basis of strength of the spectrum signal in the sleepiness level index the evaluation means evaluates the sleepiness level of the test subject, when the test subject operates predetermined equipment, and the evaluation means repeatedly calculates a peak frequency of the spectrum signal after the test subject starts operating the predetermined equipment, and when the difference between maximum peak frequency and minimum peak frequency in a predetermined time period is equal to or less than a predetermined value, an average value of the peak frequencies in the time period is set as the conscious-state peak frequency.
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Specification