| 摘要 |
PROBLEM TO BE SOLVED: To provide a shading correction method wherein, in detection of surface defects using an image, a part or all of a large-area defect flatly extending over a wide range on a surface to be inspected is not removed from an image by correction, and no rebounding phenomenon occurs in the corrected image in the vicinity of a boundary between the inside and outside of the target to be inspected. SOLUTION: Shading correction is made by detecting a boundary between the inside and outside of a target to be object from an image from a camera to detect an image region of the target to be inspected, applying a low pass filter to the image from the camera to extract a shading component as an image having the same size as that of the image from the camera, then approximating, for an image region portion to be inspected of the image, the luminance changes in lines by a curved line or the luminance change in the entire image region portion to be inspected by a curved surface, reconstructing the image region portion into an image of the same size having a value of the approximate curved line or surface as a luminance, and dividing or subtracting the image from the camera by the reconstructed image. COPYRIGHT: (C)2004,JPO&NCIPI
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