Patent ID: 8184856

Claim:
Apparatus for assessing a head pose of a driver supported on a vehicle seat including an adjustable headrest, comprising: a relative motion sensor mounted on said headrest for sensing a posterior portion of the driver's head and producing a signal responsive to motion of the posterior portion of the driver's head; and a processor for processing the signal produced by the relative motion sensor for controlling adjustment of the headrest to provide both optimal driver safety and optimal sensitivity of the relative motion sensor when determining motion of the posterior portion, and assessing whether the driver's head pose is forward or non-forward with respect to a vehicle frame of reference, wherein the processor assesses the driver's head pose as forward when the motion of the posterior portion is less than a first threshold, a steady head pose condition exists for a period of time that exceeds a second threshold, and a non-forward head pose condition exists for a period of time that exceeds a third threshold.