Object detector

An object detector comprising distance image generating means for measuring a distance from a reference position to an object to be detected present on a plane and generating a distance image of the plane and the object to be detected, and detecting means for detecting the object on the plane by using the distance image generated by the distance image generating means, wherein the object detector comprises:

• object detecting means for detecting groups of pixels separated by a prescribed height or more from the plane thus calculated as the object;
• and
• three-dimensional distribution generating means for generating a three-dimensional distribution of pixels corresponding to the plane and the object to be detected by calculating three-dimensional co-ordinate position data in a three-dimensional co-ordinate system for groups of pixels, on the basis of two-dimensional co-ordinate position data for the groups of pixels corresponding to the object as detected by the object detecting means and the distance data from the reference position, dividing a two-dimensional distribution in a depth direction Y and a height direction Z at prescribed intervals and selecting bottom point data thereof, on the basis of the calculated three-dimensional co-ordinate position data for each pixel, and determining the plane by planar approximation of the height indicated by the three-dimensional co-ordinate position data for the selected pixels.