Patent ID: 7012717

Claim:
A computer implemented method of multilevel dither screening comprising the steps of: defining a dither value for each pixel of a screening matrix; packing plural pixel values corresponding to plural pixels into equal sections of a first data word; packing plural corresponding dither values into equal sections of a second data word, said equal sections of said second data word identical to said equal sections of said first data word; adding corresponding sections of said first data word and said second data word in an arithmetic logic unit selectively spilttable into equal sections corresponding to said equal sections of said first and second data words thereby forming a sum data word; saturating any section of said sum data word that has generated a carry output during said adding to form a corresponding section of all 1's and passing other sections unchanged thereby forming a saturated sum data word; and truncating a predetermined number of least significant bits of each section of said saturated sum data word thereby forming a dither screen data word.