Patent ID: 6795573
Filing Date: 2004-09-21
Classification: G01N,G06T

Abstract:
An inspection method for inspecting an object on which a specific pattern is periodically and repetitively formed along a predetermined direction, comprising:picking-up an image of said object using not less than three gray levels; and obtaining formation information of said specific pattern by statistically analyzing a difference between a raw image obtained as an image pick-up result in said image picking-up, and a reference image, wherein said obtaining the formation information comprises: obtaining (Nâˆ’1) shift images obtained by shifting said raw image obtained in said image picking-up by integer multiples of a repetition period in a repetition direction of said specific pattern in the image pick-up result; defining as data points sets of gray levels at identical positions in N images including said raw image and (Nâˆ’1) shift images, and plotting data points corresponding to positions in overlapping regions of said N images in an N-dimensional coordinate space; and obtaining pattern formation information of said object based on a state of a distribution of said data points in said N-dimensional coordinate space.