SURFACE DEFECT DETECTION METHOD, SURFACE DEFECT DETECTION DEVICE, AND METHOD OF MANUFACTURING STEEL

摘要

PROBLEM TO BE SOLVED: To provide a surface defect detection method and surface defect detection device, which allow for accurately discriminating surface defects from scale and harmless patterns.SOLUTION: A surface defect detection method of the present invention is a method for optically detecting surface defects of steel, and includes: an irradiation step for irradiating a single inspection area with illumination rays from different directions using two or more distinguishable light sources; and a detection step for acquiring images of reflections of respective illumination rays and performing subtraction processing among the acquired images to detect surface defects in the inspection area, where resolution of the images corresponding at least to edge portions of the steel shall be no greater than 0.3 mm/pixel.SELECTED DRAWING: Figure 23