Patent ID: 6816614
Filing Date: 2004-11-09
Classification: G01R,G06T

Abstract:
A method for comparing two recorded pixel images of the same rectangular format, called source images (2a, 2b), representing in monochrome contrasted form, with E+1 possible contrast levels, equipotential lines of at least an integrated circuit chip, wherein:each source image (2a, 2b) is subjected to an adaptive thresholding processing with three distinct contrast levels, white, black and gray, called normal contrast levels, so as to assign to each pixel of the image one of these three normal contrast levels, an image, called the result image (14), is then formed from the thus processed source images (3a, 3b) by assigning to each pixel of the result image (14) a normal contrast level selected from the three normal contrast levels of white, black and gray and determined in accordance with a predetermined logical rule of comparison, according to the nature of the comparison to be made, and in accordance with the normal contrast levels assigned to the corresponding pixels of the same location of the source images (3a, 3b) on completion of the adaptive thresholding processing.