Method and apparatus for halftone rendering of a gray scale image using a blue noise mask

  • US 5,708,518 A
  • Filed: 04/11/1995
  • Issued: 01/13/1998
  • Est. Priority Date: 12/04/1990
  • Status: Expired due to Term
First Claim
Patent Images

1. A method of halftoning a gray scale image by utilizing a pixel-by-pixel comparison of said image against a blue noise mask array stored in a first memory, comprising the steps of:

  • a) scanning said gray scale image to be halftoned to create a gray scale image array on a pixel-by-pixel basis;

    b) storing said gray scale image array in a second memory;

    c) comparing, on a pixel-by-pixel basis, the value of each corresponding pixel in said blue noise mask array and said gray scale image array to produce a multibit image array; and

    d) converting said multibit image array to the desired halftoned image, wherein said halftoned image of said gray scale image is a multi-toned image having multiple gray scale levels.

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