Patent ID: 9053410
Filing Date: 2015-06-09
Classification: G06K,H04N

Abstract:
1. A method of generating a screened multi-bit data output file for a digital printing machine having the ability to print on a page a first printable tone level, a second printable tone level, and a third printable tone level, from an unscreened raster data file specifying a continuous tone value for a first colorant for each printable position of the page, the method comprising the steps of: (a) creating first and second tonal sub-ranges corresponding to the first and second printable tone levels, respectively, for the first colorant; each of said first and second tonal sub-ranges comprising beginning and ending boundary tone values defining first and second tone range spans and a first transition tone value to be both said ending boundary tone value of said first tonal sub-range and said beginning boundary tone value of said second tonal sub-range; (b) shifting the position of said first transition tone value so that said first tone range span is different from said second tone range span; (c) producing a modified output tone value for said first and second tonal sub-ranges by first and second tone modification functions, respectively; and (d) producing a single multi-bit output value corresponding to the first colorant for each printable position on the page by using said modified output tone values of said first and second tone modification functions as inputs to at least one bi-level half-toning algorithm.