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MINIMAL WEIGHTS FOR EFFICIENT ERROR DIFFUSION

IP.com Disclosure Number: IPCOM000027516D
Original Publication Date: 1997-Jun-30
Included in the Prior Art Database: 2004-Apr-08
Document File: 2 page(s) / 91K

Publishing Venue

Xerox Disclosure Journal

Abstract

Error diffusion is a halftoning process which provides a stochastic response. As described by Floyd and Steinberg, the process operates by thresholding each input signal to produce an output signal at a predetermined number of possible levels, determines the difference between the thresholded output signal and the input signal, and distributes the difference to a predetermined set of neighboring, unprocessed pixels. Floyd and Steinberg proposes a distribution pattern as follows:

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XEROX DISCLOSURE JOURNAL

MINIMAL WEIGHTS FOR EFFICIENT Proposed Classification ERROR DIFFUSION U. S. C1.358/458 David A. Mantell Int. C1. H04n 1/40

Error diffusion is a halftoning process which provides a stochastic response. As described by Floyd and Steinberg, the process operates by thresholding each input signal to produce an output signal at a predetermined number of possible levels, determines the difference between the thresholded output signal and the input signal, and distributes the difference to a predetermined set of neighboring, unprocessed pixels. Floyd and Steinberg proposes a distribution pattern as follows:

where each block represents a pixel that is a neighbor to pixel X, and where each of the factors {7,3,5,1} is multiplied by Thus, for a determined error E, 7/16 E is passed to pixel (n+l, I), 3/16 E is passed to pixel (n-1,1+1), E is passed to pixel (n, 1+1), and '/16 E

is passed to pixel (n+l, l+l),

U.S. Patent No. 5,353,127 to Shiau et al. teaches that error can be distributed in a manner that minimizes directionalized worming artifacts. Generally speaking, the distribution scheme can be expressed as follows:

This distribution scheme was proposed based on the hypothesis that worm creation was a result of the lack of error distribution beyond the direction of the diagonal defined by pixel (n,l) and pixel (n-I, l+l). The added distribution to pixels (n-2, l+l), and (n-3, 1+1) were combined with the elimination of distribution to pixel (n+l, l+l). Setting the error

XEROX DISCLOSURE JOURNAL - V...