Two-dimensional images of a three-dimensional body photographed by two video cameras are parallactically compensated prior performing the detection of the corresponding point necessary to recognize the body. Namely, the parallax between both cameras for the object distance measured by a range finder is calculated by a parallax calculator, and one image is electrically shifted by an image shifting circuit by only the number of pixels in accordance with the parallax value, thereby performing the parallax compensation of the images. In a calculation processing unit, the correlation values for the corresponding points between both images are calculated, and the distance images of the body are produced on the basis of these correlation values.