PICTURE PROCESSOR

PURPOSE:To obtain the linear ridgeline of an object with high accuracy and high efficiency by carrying out the straight line extracting processing based on the absolute differential value of the picture data storing in a segmented minor picture area. CONSTITUTION:The differential filter processing is first applied to the picture data stored in the 1st picture memory 8 via a differential filter circuit 9. Then the absolute value filter processing is applied to said picture data via an absolute value filter circuit 11. A microcomputer 14 detects the position of a vertical ridgeline and the area of a horizontal ridgeline is decided from the position of the vertical ridgeline. Then the picture data stored in the horizontal ridgeline area is rotated by a fixed angle and extracted out of the memory 8. This picture data also undergo the differential filter processing and the absolute value filter processing. These obtained differential and absolute values are added together via a peripheral distribution calculation circuit 13a in the direction perpendicular to the differential direction. Thus the distribution curve of the absolute value is obtained. Then the apex of said distribution curve is obtained and the lateral ridgeline is obtained from the picture data on said apex area.