Apparatus for detecting occupant's posture

Abstract

An apparatus for determining an occupant's posture is provided which includes a sensor having at least one pair of linear photosensor arrays each comprising a plurality of photosensor elements, for forming an image of an occupant, a distance measurement processor that derives distance distributions in fields of view monitored by the linear photosensor arrays, from the image of the occupant formed by the sensor, and an occupant discrimination processor that compares patterns of the distance distributions with model patterns of distance distributions preliminarily stored in the processor, so as to determine the presence and posture of the occupant. The linear fields of view are set to extend in a substantially horizontal direction with respect to the occupant, and the occupant discrimination processor first examines at least one of symmetry of the distance distribution pattern in each field of view, concave or convex shape of the pattern, degree of similarity in variations in the distance distribution patterns between adjacent fields of view, and a distribution of distances measured at a particular position of the fields of view, and then determines the posture of the occupant by comparing the patterns of the distance distributions actually measured, with a group of model patterns that is selected in advance depending upon the result of the examination.