| 摘要 |
PROBLEM TO BE SOLVED: To provide a shading correcting apparatus of making uniform the lightness distribution of light parts and the lightness distribution of dark parts as well as the average lightness of an image under illumination having a shading pattern wherein the light parts and the dark parts alternate. SOLUTION: The shading correcting apparatus includes an illumination means for illuminating the surface of the subject of inspection with the shading pattern wherein the light parts and the dark parts alternate, for inspecting the surface of the subject of inspection, an image pickup means for picking up images of the subject of inspection illuminated with the shading pattern, and a shading correction means for eliminating the shading components of the image pickup means according to original image date obtained by the image pickup means. The shading correction means calculates average lightness curve data, the envelope data of the light parts, and the envelope data of the dark parts from the original image data having the shading pattern, and corrects, the original image data by use of these data so that the shading components are eliminated from the average lightness distribution of the original image data, the lightness distribution of the light parts, and the lightness distribution of the dark parts.
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