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Improved Pel Selection for Grey Scale Representation

IP.com Disclosure Number: IPCOM000041433D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02

Publishing Venue

IBM

Related People

Authors:
Haigh, DC [+details]

Abstract

The technique described in this article addresses the problem of how to choose which of the picture elements (pels) in a rectangle to make black, having previously determined how many should be black. A technique that is widely used to represent grey scales with pels that can only be either black or white is to divide the image into equal sized rectangles (typically 3 to 5 pels per side) and then to make an appropriate proportion of the number of pels inside each rectangle black, the appropriate proportion of black and white pels being determined by the level of grey that it is desired to represent. If the size of each rectangle is m X n pels, then it is possible to represent (m X n)+1 different grey levels, ranging from completely white to completely black.