Patent ID: 6185005
Filing Date: 2001-02-06
Classification: H04N

Abstract:
A method for halftoning in an area defined by a matrix of pixels comprising:partitioning the area into a plurality of macro halftone cells, each macro halftone cell being constituted by an array of contiguous pixels;defining a plurality of ranking levels, each ranking level being associated with a linear function of a desired level of apparent color intensity in a macro halftone cell region, a highest ranking level being associated with a minimum apparent color intensity and a lowest ranking level being associated with a maximum apparent color intensity;allocating to each ranking level one or more pixels of each macro halftone cell such that the pixels of the macro halftone cell are non-uniformly distributed among the plurality of ranking levels;selecting one of the ranking levels for each macro halftone cell based upon an input value associated with the macro halftone cell; andin each macro halftone cell, darkening each pixel allocated to a ranking level greater than the ranking level selected for the macro halftone cell,wherein the pixels of each macro halftone cell are non-uniformly allocated among the ranking levels such that the apparent level of color intensity of each macro halftone cell is linearly proportional to the associated input value.