IMAGE PROCESSING METHOD, SUBSTRATE INSPECTION METHOD, SUBSTRATE INSPECTION APPARATUS AND METHOD OF GENERATING SUBSTRATE INSPECTION DATA

A color image as a combination of color data corresponding to a plural n-number of different hues is processed by extracting a target object from the image and carrying out a specified image processing. A reference image is obtained in the absence of the target object. Color data corresponding to specified less than n of the different hues are considered and difference in the degree of intensity of the considered color data relative to the combination of color data corresponding to n different hues between each pixel of the target image containing the target object and a corresponding pixel on the reference image are extracted. Pixels for which the extracted difference is greater than a specified threshold value and is in a specified direction are extracted. An image area formed by the extracted pixels are recognized as the target object.