| 摘要 |
PURPOSE:To execute an inspection close to a visual inspection, by masking an output converted in gradation, performing a correlative operation not related to a subtraction of the average density of a to-be-inspected image, and obtaining a density data of pixels. CONSTITUTION:A calculating part 4 obtains a binary image distinguishing a mark part and a background part of a reference image corresponding to a to-be-inspected image 1 so as to increase the ratio of a defective part to the mark part. Parts other than the mark part are masked based on the binary image. The gradation between a reference ground and the mark part is widened. At this time, the background part of the binary image is used as a reference. The obtained gradation-converted output is turned, according to an operation 8 not related to a subtraction of the average density of the image 1, to a value of the density of the image 1 corresponding to that observed by eyes. The size of the defect of the image 1 is detected from the result of the correlative operation without normalization at a detecting part 9 to judge whether the mark part of the image 1 is good or not. |
