DEFECT DETECTING DEVICE AND DEFECT DETECTION METHOD

PROBLEM TO BE SOLVED: To reduce the influence by the noise components contained in an inspection image, when detecting a gray level difference or determining a detection threshold, in defect inspection for detecting the difference between each pixel, by comparing the gray level difference between each pixels which should be mutually identical, with a prescribed detection threshold. SOLUTION: When it is determined whether a defect exists in an inspection pixel 71 in the inspection image 61, wherein the same unit patterns 51-55 appear repeatedly, some of pixel values of at least three pixels among pixels 72-75, respectively corresponding to the inspection pixel 71 is selected as a reference pixel value, in the inspection pixel 71 and in a plurality of other unit patterns 52-55 which are different from the unit pattern 51 that contains the inspection pixel, and the reference pixel value is compared with a pixel value of the inspection pixel 71, to thereby determine whether the inspection pixel 71 is a defect candidate. COPYRIGHT: (C)2009,JPO&INPIT