Automatic image segmentation using local area maximum and minimum image signals

摘要

Method and apparatus for processing image pixels to determine the presence of high frequency halftone images. Prior to auto correlation, each pixel in the image is examined to determine whether it is a local area maximum or minimum. A binary image function composed of the image local area maximum or minimums is made available for auto correlation. The presence of peaks at shifts indicative of predetermined halftone image frequencies is detected, and an output signal indicative of the presence or absence of peaks at the predetermined halftone image frequencies is provided. The arrangement is combined with a run length encoder to reduce false microdetection results.