The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 17, 2007
Filed:
May. 25, 2004
Taiji Kawachi, Kariya, JP;
Tsuyoshi Nakagawa, Aichi-gun, JP;
Akiko Ito, Nagoya, JP;
Takeshi Yoshinori, Okazaki, JP;
Taiji Kawachi, Kariya, JP;
Tsuyoshi Nakagawa, Aichi-gun, JP;
Akiko Ito, Nagoya, JP;
Takeshi Yoshinori, Okazaki, JP;
Denso Corporation, Kariya, JP;
Abstract
A sleepiness level detection device detects a heartbeat signal when a time equal to or longer than Tand equal to or shorter than Thas 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.