| 摘要 |
PURPOSE: To attain the discrimination of the kind of an irregularity defect with high accuracy by calculating a feature amount showing the feature of the defect, and discriminating the defect according to the feature amount. CONSTITUTION: An image signal is obtained by photographing the illuminated surface of a subject to be inspected. In accordance with the image signal, a defective region corresponding to a defect in the surface of the subject to be inspected is extracted from within an image showing the surface of the subject to be inspected, and average values of image signals corresponding to the overlapping portions of the defective region with a plurality of partial regions obtained by the dividing of the inside of the rectangular region into plural (three) parts by one side of the contour of the rectangular region, e.g. a line parallel to the Y axis, are calculated. The plurality of average values are digitized by comparison of the plurality of average values with one or plural thresholds. A feature amount showing the feature of the defect is calculated on the basis of a pattern of arrangement of the plurality of these numerical values, and the defect is identified according to the feature amount. |
