US Patent 7068852 Edge detection and sharpening process for an image

A method and device for sharpening detected edges in an image to compensate for a corruption that occurs during the scanning and printing processes. Edges are enhanced by increasing the contrast between two sides of an edge region according to the amount of distortion in the image signal at that location. Each pixel in the image is analyzed in the context of neighboring pixels in the image to determine the presence of an edge and the degree of sharpening required. A filter is applied to adjust the intensity value of pixels in an edge region to correct for distortion and to emphasize the edge. The resulting final image contains sharpened edges with little effect on the smooth transition regions of the image.