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

  • US 5,477,305 A
  • Filed: 11/22/1994
  • Issued: 12/19/1995
  • Est. Priority Date: 12/04/1990
  • Status: Expired due to Term
First Claim
Patent Images

1. Apparatus for performing the halftoning of a gray scale image by utilizing a pixel-by-pixel comparison of said image against a blue noise mask array, comprising:

  • a) a first memory for storing said blue noise mask array;

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

    c) a second memory for storing said gray scale image array;

    d) a comparator for 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 binary image array; and

    e) a converter for converting said binary image array to the desired halftoned image.

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