Patent ID: 7298897

Claim:
A computer-based method for converting a gray-scale multiple pixel image to a binary image comprising the steps of: a) loading a gray-scale image from an external source of images into an operating memory of a computer; b) determining an optimal threshold value for converting said gray scale image to binary by executing an application with said computer, said application carrying out the steps of: 1) forming a fuzzy membership function which identifies a membership value for each pixel in said image, said membership function including a first group of gray level values at or below a selected intensity threshold that are designated as corresponding to pixels belonging to a first characteristic class of the image and a second group of gray level values above said selected intensity threshold that are designated as corresponding to pixels belonging to a second characteristic class of said image, said first and second classes being selected from the group comprising a background class and a foreground class; 2) calculating an entropy factor for each possible membership value by applying a linear entropy factor function to said membership values; 3) employing said entropy factor to calculate a fuzzy entropy measure for said image with said selected intensity threshold; 4) repeating steps (1)-(3) for a plurality of additional selected intensity thresholds; 5) selecting as optimal, a one of said intensity thresholds that provides the lowest fuzzy entropy measure; and c) converting said gray scale image to a binary image using said optimal intensity threshold by assigning any pixels in said gray scale image having a gray level above said optimal intensity threshold to a first binary value and assigning any pixels in said gray scale image having a gray level at or below said optimal intensity threshold to a second binary value.