Patent ID: 6836561
Filing Date: 2004-12-28
Classification: G06T

Abstract:
A method for detecting a defect on an object having a plurality of projected portions formed along an arc with a predetermined pitch, the projected portions being separated by a plurality of cut-away portions, the method comprising:determining an arc circumscribing a tip of each projected portion of the object; identifying a plurality of overlapping regions formed by an overlapping portion between an inner portion of a region defined by the arc and the plurality of cut-away portions, and determining an area corresponding to each of the overlapping regions; comparing the area of each of the overlapping regions with the areas of the other overlapping regions to determine an area difference for each of the overlapping regions; and determining that no defect exists on the object when the area difference of each of the overlapping regions is within a range of predetermined criteria, and determining that a defect exists on the object when the area difference of at least one of the overlapping regions is outside the range of predetermined criteria.