METHOD AND APPARATUS FOR INSPECTING SURFACE OF METAL

摘要

PROBLEM TO BE SOLVED: To accurately discriminate a flaw part from a foreign matter on the basis of image data obtained by photographing the surface of a metal. SOLUTION: B, G and R are respectively alotted to respective image data obtained by photographing the surface of the same metal from above under respective illuminations of high, medium and low angles to synthesize three image data and the surface state of the metal is inspected on the basis of the synthesized input image of a RGB color. At this time, a flaw having an edge is discriminated from the presence only of the medium/low angle illumination reflecting part (C) large in reflection intensity under both illuminations of medium and low angles and a contact flaw is discriminated from the presence only of the high angle illumination reflecting part (E) larger than the surface part of the metal in reflecting intensity under high angle illumination and bonded foreign matter is discriminated from the proximity presence of the medium/low angle illumination reflecting part (C) and the high angle illumination reflecting part (E).