IMAGE PROCESSING METHOD, IMAGE PROCESSING APPARATUS, PROGRAM AND RECORDING MEDIUM

PROBLEM TO BE SOLVED: To provide an image processing method, an image processing device, a program, and a recording medium capable of detecting defects of irregularities and stabilizing inspection, independently of the type of tire, the state of tire surface, and positional relation of illumination. SOLUTION: A control part 12 determines whether defect candidates are large-scale defects of irregularities on the basis of a differential value obtained by differentiating the density of each pixel in a first direction, for example a rotation direction of a tire, on the basis of a dedicated threshold predetermined for each type of irregularities. Next, on the basis of the differential sum obtained by adding the differential values obtained by differentiating the densities of pixels, it is determined whether it is a small-scale concavity defect about a predetermined differential range in the first direction with the position of a pixel having the minimum density from among the pixels constituting the image as the center. Further, it is determined whether it is an acute angle concavity defect on the basis of the differential value at a predetermined differential width in the first direction with each pixel as the center. COPYRIGHT: (C)2011,JPO&INPIT