Patent ID: 6249608
Filing Date: 2001-06-19
Classification: G06K,G06T

Abstract:
An image processing template matching method, used in a calculation device for performing image processing, for evaluating a similarity between a template image and sub-images, contained within a search image, having a size equal to the size of the template image, based on a normalized correlation coefficient, and determining a sub-image resembling said template image in accordance with results of evaluating a similarity, said method comprising the steps of:obtaining a sum (A) of image data values of pixels in a template image, a sum (B) of squares of image data values of pixels in said template image, a sum (C) of image data values of pixels in one of said sub-images to be processed, a sum (D) of squares of image data values of pixels in said sub-image;obtaining a threshold value (F), based on equation 1, ##EQU5##where (P) is the number of pixels in said template image, and (E) is a preset positive value of less than 1;obtaining a square of a difference between an image data value of a pixel in said sub-image to be processes, and an image data value of a corresponding pixel in said template image;performing cumulative addition for said obtained square; andrepeating the step of obtaining a square and the step of performing cumulative addition;if a result of said cumulative addition exceeds said threshold value, closing evaluation of a similarity for said sub-image, and, if a result of said cumulative addition for all pixels of said template image does not exceed said threshold value, calculating a similarity value by using said cumulative addition;determining a matching point in said search image by evaluating all similarity values after all evaluations of sub-images terminate; andstoring said matching point in a memory in said calculation device.