Patent ID: 6643032
Filing Date: 2003-11-04
Classification: H04N

Abstract:
A halftone cell having a plurality of consecutive graduated output levels responsive to an input intensity value of an input pixel, said halftone cell comprising:a matrix of subpixels corresponding to the input pixel, each subpixel having a binary output including a first subpixel output level and a second subpixel output level, said matrix being divided into a plurality of distinct subsets of subpixels such that with progressively higher input intensity values of the input pixel, progressively more subsets of subpixels switch their binary output from the first subpixel output level to the second subpixel output level, each switch of one subset of subpixels corresponding to one increase in the graduated output level of the halftone cell; wherein the subsets of subpixels are arranged so that, when progressing from a lowest to a highest input intensity value of the input pixel, the subpixels switching to the second subpixel output level form a cluster of neighboring subpixels which grows outward from a center of the matrix to a periphery of the matrix, each subset of subpixels including a number of subpixels such that said halftone cell exhibits substantially linear perceived intensity changes between consecutive graduated output levels thereof, said plurality of distinct subsets of subpixels including at least two subsets of subpixels having numbers of subpixels different from one another.