Patent ID: 8391585

Claim:
A defect detecting device that detects, from a digital image, a defective area where a pixel value changes more unevenly than a pixel value in an area surrounding the defective area does, the defect detecting device comprising: an edge detection section that carries out manifestation of an edge of a defect in a pixel value of an inspection-target image, a pixel value correcting section that corrects the pixel value where an edge is detected, on which detection of the defective area is to be carried out, in such a manner that a pixel value corresponding to an area that is to be detected as the defective area is emphasized with respect to a pixel value of an area other than the defective area; and a block-division processing section that divides the inspection-target image into plural blocks and obtains a block addition value, which is a value obtained by adding pixel values of pixels present in a block, or a block mean value, which is a value obtained by dividing the block addition value by the number of pixels in the block, the block addition value or the block mean value being supplied to a defective-area presence determining section that determines whether the defective area is present or not, by carrying out statistical processing to determine whether an outlier of the block addition value or an outlier of the block mean value is present or not, wherein the pixel value correcting section corrects the pixel value of the inspection-target image on which the block-division processing section has carried out processing to divide the inspection-target image into plural blocks and to obtain the block addition value or the block mean value of the inspection-target image.