The detection of the sleepiness from the sounds obtained inside of the body

This paper shows that the detecting method of the sleep-in sleep state or sleepiness from the sound signals in the human body. Former report we showed that the detection of the sleepiness concerns with the piezoelectric sensors attached on car seat. Our preliminary examination showed that the spectrum of signals from the piezoelectric sensor have the tendency that the shapes of the spectral envelopes are flattened. And the sounds in human body are considered to have similar features. In this experiment, the signals of the piezoelectric sensor on the seat and the sounds in the human body are measured at the same time and the relation between the sounds and sleepiness are examined. The sounds inside the body are measured using NAM microphone system. The spectral envelopes of the signals from the left side and the right side of breath are calculated. The spectral envelopes from the seat are calculated at the same time. 27 measurements by four examinees are done and 11 sleeping data are measured. Flatness of the envelopes is defined using the lower order of cepstral coefficients and the increase of the flattened spectrum is observed by the sounds from the sleeping data of three quarters.