Patent ID: 8023744

Claim:
A pattern matching system that outputs a likeness value showing how much a first and a second image compare to each other, said pattern matching system comprising: a designation block that designates as data to be compared first and second digital image data comprising all pattern area data generated from individual pattern areas in said first and second images, respectively, and said first and second digital image data not including any area data generated from pattern areas outside of said first and second images, said first and second digital image data comprising 2^x number of pattern area data wherein x is a positive integer, data levels of said pattern area data varying according to the intensity of light incident to a pattern area, said first and second images comprising 2^x number of said pattern areas; a comparison block that compares said data levels of said pattern area data corresponding to said pattern areas at the relatively same location in said first and second images; a calculation block that calculates said likeness value, said likeness value varying according to the number of said pattern areas where the absolute value of the difference between said compared data levels of said pattern area data of said first and second images is less than a predetermined standard value; and an output block that outputs said likeness value, wherein said pattern area is broadened when the intensity of light of said entire first or second image is lower than a first threshold value.