Patent ID: 6320977
Filing Date: 2001-11-20
Classification: G06K

Abstract:
A method comprising the steps of:generating a first signal representing an image of an object to be inspected;selecting portions of the first signal as second signals respectively, the second signals representing respective partial images of the inspected-object image, the partial images being of a given size;comparing the second signals with a third signal representing a predetermined reference image of a size equal to the size of the partial images, executing pattern matching between the partial images and the reference image, and calculating scores of the pattern matching between the partial images and the reference image;selecting a maximum score from among the calculated scores;generating a fourth signal representing a position of the partial image corresponding to the maximum score, the partial-image position being relative to the inspected-object image;determining an invalid area of the reference image according to a fifth signal representing a predetermined unreliable image area; andexcluding a part of the third signal, which corresponds to the invalid area of the reference image, from the pattern matching.wherein the predetermined unreliable image area is an area within the reference image which fails to provide an accurate indication of an actual appearance of a corresponding area of the reference image due to reflection of light.