Patent ID: 6124844
Filing Date: 2000-09-26
Classification: H04N

Abstract:
A method of halftoning an image, said image comprising a plurality of pixels each having an input value and an assignable output value that can take on one of at least two output values, said method comprising, for a current pixel of said image, the steps of:(a) determining an under result and an over result for the current pixel and for a plurality of previously halftoned pixels of said image, wherein said under result and said over result for a pixel are dependent upon an output value assigned to that pixel;(b) determining using the under result and the over result for the current pixel and for the plurality of previously halftoned pixels, an under result repulsive measure and an over result repulsive measure for the current pixel, whereby said under result repulsive measure is dependent upon a sum, over the plurality of previously halftoned pixels, of a product of the under result for the current pixel and the under result for a previously halftoned pixel, and whereby said over result repulsive measure is dependent upon a sum, over the plurality of previously halftoned pixels, of a product of the over result for the current pixel and the over result for a previously halftoned pixel;(c) comparing the under result repulsive measure to the over result repulsive measure; and(d) assigning a first output value as the output value for the current pixel in the event that the under result repulsive measure is greater than the over result repulsive measure, and assigning a second output value as the output value for said current pixel in the event that the over result repulsive measure is greater than the under result repulsive measure.