Processing used to represent a gradation by changing the number of black pixels and the number of white pixels in a matrix of 8.times.8 pixels. First, edge information sampled from the input data is allocated to corresponding pixel positions of the output data with priority. A residual gradation value...http://www.google.fr/patents/US4667250?utm_source=gb-gplus-shareBrevet US4667250 - Halftone digital image processing device
