Abstract:
It is possible to realize a highly accurate defect inspection by correcting image acquisition distortion by utilizing only the image information on an observation image and a reference image. The distortion amount is expressed by a distortion building coefficient and a distortion parameter. In optical simulation execution means (21), a reference image is generated from design data. Next, in distortion amount estimation means (22), a distortion parameter is calculated by using the observation image, the reference image obtained by the optical simulation execution means (21), and a preset distortion building coefficient. The distortion parameter is stored in a distortion parameter storage unit (32). Next, distortion image creation means (23)calculates a distortion amount of the observation image from the distortion parameter by using the distortion building coefficient. Furthermore, the distortion image creation means (23) distorts the reference image by the distortion amount. The reference image distorted by the distortion image creation means (23) is supplied to image comparison means (24). Here, the observation image is compared to the reference image supplied from the distortion image creation means (23) and a portion having a large difference is decided to be a defect.