| 摘要 |
PURPOSE:To enable the decision of a defect level with high accuracy by using an If-then type rule. CONSTITUTION:The surface of a material to be inspected is irradiated with laser beam while scanning laser beam in the direction rectangular to the carrying direction, a signal obtained by photoelectric conversion of the reflected light of laser beam is passed through a differential filter, and an inspection signal is acquired. The two-dimensional image of the material to be inspected is formed on the basis of a signal obtained through a plurality of scanning. There are a defective section 1a more projecting than a flaw-free section and a defective section 1b more recessed than the flaw-free section in a defect 1 in width W and length L in the surface of the material to be inspected. Thresholds TH1-TH3 are predetermined in order of the lower degrees of the defects in the section 1a and thresholds TH4-TH6 similarly even in the section 1b. The sections 1a, 1b are quantized by using the thresholds TH1-TH6, and the areas ATH1-ATH6 of regions quantized at the same level are acquired. The number of the components of the area AYTH1-ATH6 is obtained, the number of defects measured in an inspection region is acquired, and the levels of the detects are decided by an If-then type rule. |
