Patent ID: 8140149
Filing Date: 2012-03-20
Classification: A61B,B60K,B60W,G08B

Abstract:
1. A drowsiness detector comprising: a measurement means for measuring a heartbeat or a pulse of a subject; a pulse feature value extracting means for extracting a pulse feature value from the heartbeat or the pulse measured by the measurement means; a variation distribution calculating means for calculating variation distribution of the pulse feature value extracted by the pulse feature value extracting means; and a drowsiness level determining means for determining a drowsiness level of the subject using the variation distribution of the pulse feature value calculated by the variation distribution calculating means, wherein the variation distribution calculating means has a means for calculating a standard deviation of the pulse feature value as the variation distribution of the pulse feature value and a means for correcting the standard deviation of the pulse feature value by dividing the standard deviation of the pulse feature value by the pulse feature value acquired in a state where there is no drowsiness, and the drowsiness level determining means determines the drowsiness level of the subject on the basis of the standard deviation of the pulse feature value, and the pulse feature value includes at least one of a pulse fluctuation low-frequency component relevant to the activity of the sympathetic nerve, a pulse fluctuation high-frequency component relevant to the activity of the parasympathetic nerve, and a ratio of the pulse fluctuation low-frequency component and the pulse fluctuation high-frequency component.