IMAGE PROCESSING DEVICE, PLANE DETECTION METHOD, AND RECORDING MEDIUM UPON WHICH PLANE DETECTION PROGRAM IS RECORDED

The image processing device includes: a distance image capture device which captures a distance image based upon three dimensional coordinate values obtained, by measuring the distances to various points upon body surfaces in the forward visual field of a distance sensor, for those points upon those body surfaces; a straight line extraction device which obtains three dimensional coordinate values of two points from a viewpoint picture element in the distance image and a picture element which is separated by a predetermined distance from that viewpoint picture element, and which extracts a plurality of straight lines in a horizontal plane using two dimensional coordinate values by ignoring the vertical component among these three dimensional coordinate values; and a plane detection device which obtains points on the body surfaces which lie upon various straight lines which have been extracted by the straight line extraction device, and detects points which lie upon the same straight line as being upon the same vertical plane.