Patent ID: 7084773

Claim:
An apparatus for estimating wakefulness of a driver comprising: a frequency analyzing process unit, for calculating an average value of a quantities of the frequency power components as a quantity of high frequency components, wherein the quantities of the frequency power components are calculated by performing frequency transformation of displacements of a vehicle in the width direction detected as a time series, and for calculating a maximum value of the quantities of frequency power components within a predetermined frequency range as a quantity of low frequency components, wherein the predetermined frequency range includes a stagger frequency exposed when the driver is at a low level of wakefulness; an estimated wakefulness value calculation unit for calculating an estimated value of wakefulness from the ratio of the quantity of the high frequency components to the quantity of the low frequency components; and a road-shape-based wakefulness value correction unit for correcting the estimated value of wakefulness according to a road condition, wherein the road-shape-based wakefulness value correction unit includes: a steering angle integration unit, for determining a magnitudes of steering angles based on steering angles detected by a steering angle sensor, and for integrating steering angles determined to be small angle; and a steering angle determination unit for determining whether the integrated value of the steering angles is within a set range of steering angles, and wherein the estimated value of wakefulness is corrected when the integrated value of the steering angles is within the set range of steering angles.