| 摘要 |
PROBLEM TO BE SOLVED: To certainly detect a pattern-like scab flaw having no marked unevenness like the crack, dent or tear-off of a surface to be inspected. SOLUTION: Polarized light is allowed to be incident on the surface of a steel panel 4 at a constant incidence angle, and the intensities of polarized lights different in angle of the reflected rights thereof are detected by light detection camera units 25a-25d. A signal processing part 30 detects a combination pattern of the width and length of the flaw in a flaw candidate region, the density peak value of the flaw part with respect to polarized lights different in angle and the polarity of a density integrated value based on a normal part as characteristic quantity to judge the kind of a flaw.
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