Surface defect detection device, surface defect detection method, and steel manufacturing method

摘要

PROBLEM TO BE SOLVED: To provide a surface defect detecting device and a surface defect detecting method capable of accurately detecting a surface defect. SOLUTION: The surface defect detection method according to the present invention is a first or first method from a difference image generation step of generating a difference image between a first image and a second image, and a bright part and a dark part of the difference image. The combination of the bright part and the dark part of the convex portion in the inspection target part is extracted and extracted based on the arrangement of the bright part and the dark part along the predetermined direction of the difference image corresponding to the irradiation direction of the illumination light of the second irradiation means. It is characterized by including a surface defect detection step of detecting a surface defect based on the brightness of the positions of the first image and the second image corresponding to the positions of the bright and dark areas. [Selection diagram] FIG. 9