Patent ID: 6195467
Filing Date: 2001-02-27
Classification: G06T,H04N

Abstract:
A process for enhancing a digital grayscale image, comprising the steps of:(a) selecting a digital grayscale image, said image comprising a matrix of pixels, each of which has a characteristic grayscale value associated therewith;(b) applying a convolution window to said image, said convolution window having an odd number of pixels therein including a central pixel Pc and neighboring pixels Pn;(c) identifying the central pixel within said convolution window;(d) comparing the characteristic grayscale values of a plurality of selected pairs of pixels within said convolution window, said comparing step for each selected pair of pixels yielding a vector comprising an indication of the magnitude of the change in value between said selected pair of pixels and an indication of the direction of said change in value;(e) comparing said magnitude of each said selected pair of pixels to a threshold value, and if said magnitude is less than or equal to said threshold value, selecting the next of said selected pairs of pixels within said convolution window, and repeating steps (c) through (e), until all of the selected pairs in said convolution window have been compared and thereupon, proceeding to step (h); however(f) if said magnitude is more than said threshold value, counting the number of each of said vectors whose magnitudes have surpassed said threshold value;(g) repeating steps (c) through (f), until all of the selected pairs in said convolution window have been compared;(h) adjusting the grayscale value of said central pixel as a function of the number of vectors counted;(i) outputting the adjusted value of said central pixel; and(j) stepping said convolution window to the next pixel, and repeating steps (c) through (j), until all the pixels of said image have been processed as central pixels.