Patent ID: 7084772

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 a 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 high frequency components to the quantity of low frequency components; and an alarm control unit for setting an imaginary deviation line between a lane marking extending on a side the vehicle and the vehicle with a predetermined interval from the lane marking according to the estimated value of wakefulness and issues an alarm when a deviation from the imaginary deviation line occurs.