Method and apparatus for digital scale halftoning with variable screen structure for electrophotographic printing devices

摘要

A method and apparatus for modifying a digitized image in which the digitized image is received as input pixel values for a plurality of pixels, first selects an unprocessed one of the pixels to be a current pixel. The current pixel is modified by adding a total error value and a screen frequency component to the input pixel value of the current pixel to produce a modified current pixel value. The modified current pixel value is thresholded to produce an output pixel value for the current pixel, which becomes a processed pixel. The output pixel value is then mapped into an image range, and a total error incurred for the processed pixel caused by the mapping is determined. The total error incurred is distributed to at least one of the other of the plurality of pixels that is an unprocessed pixel. The procedure is repeated for each pixel in the plurality of pixels to provide a modified digitized image.