Canon Information Systems Research Australia Pty. Ltd.

Canon Aptex

Peter William Ilbery

A method and apparatus are disclosed which permit a seamless halftoning of an image by halftoning regions of the image independently and/or in parallel. Each region of the image being arbitrarily determined, and being halftoned on the basis of halftoned pixel results of pixels within a predetermined neighborhood of the region. The arrangement providing a greater flexibility in the independent halftoning of the regions, while providing substantially seamless joins between abutting halftoned regions of the image. Further, the arrangement also provides a mechanism for parallel processing (halftoning) of abutting regions of an image with substantially seamless results.

Seamless parallel neighborhood process halftoning

An image processing system in which a computer image is halftoned by halftoning a current pixel using error diffusion, with a halftoned output value of the current pixel being determined using errors derived from substantially all previously halftoned pixels of the image. Output error values are determined for each pixel, and are acted upon by an error diffusion mask of geometrically reducing values. In certain instances, previously halftoned pixels are divided into two or more groups to obtain a desired contribution from previously halftoned pixels.

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Dundas, Australia

Peter William Ilbery