| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a surface inspection apparatus by which a defect is detected with high accuracy by detecting a patternlike scab defect having no remarkable uneven property such as a crack, a twist or a burr on a surface on a face to be inspected surely. SOLUTION: In a signal processing part 31, an output image signal from a linear array camera which is arranged so as to be at 0 deg., 45 deg. and -45 deg. is shading-corrected, it is normalized and flattened in such a way that a normal part becomes a center density in the whole gradation, and it is converted into an image signal which indicates a relative change to the normal part. The changed polarity and the changed amount of the distribution of three kinds of light intensity signals indicating the relative change to the normal part are compared respectively with a predetermined pattern, and a change in polarized light is detected. The flaw seed of a flaw whose physical property on the surface is different from that of a base material is judged on the basis of the magnitude of the change polarity and the change amount with reference to the normal part of the three kinds of light intensity signals.</p> |
