Hierarchical template-matching filters

摘要

The present invention is a method and apparatus for performing filtering operations on a digital image One embodiment is enhancement of the contour fidelity of the image represented by a plurality of pixels, by storing pixel values representing a segment of the image in memory; isolating a plurality of regions of the pixels of said image segment to form a plurality of windows including a central pixel and a plurality of pixels surrounding said central pixel. Then comparing at least two of the regions of pixels within the windows with a set of standard pixel patterns for each of the windows and identifying matching pixel patterns within each of the windows. When matching patterns are identified, enhancing one or more pixels located at a correctable position when the central pixel is located at a correctable position in a plurality of the windows wherein the enhancement is accomplished in accordance with an enhancement associated with one of the windows and wherein the enhancement is determined in accordance with a predetermined hierarchy for the windows. <IMAGE>