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From: don@allegra.UUCP (Don Mitchell)
Newsgroups: net.graphics
Subject: bilevel display
Message-ID: <5748@allegra.UUCP>
Date: Sun, 9-Feb-86 16:26:26 EST
Article-I.D.: allegra.5748
Posted: Sun Feb  9 16:26:26 1986
Date-Received: Tue, 11-Feb-86 06:32:39 EST
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 22

Another useful paper on halftoning (simulating gray scale on bilevel
displays) is

	Stoffel, J.C, "A Survey of Electronic Techniques for
	Pictorial Image Reproduction". IEEE Trans. Comm.,
	Vol COM-29, No 12, December 1981.

This paper discusses electronic screening techniques (unlike Jarvis)
which I believe is a much better for printers.  It produces images
much like you find in newspapers.  Ordered dither and Floyd-Steinberg
tend to generate very high frequencies which make a mess when you try
to print or xerox them.

Electronic screening is done like ordered dither, but with a very different
threshold matrix.  For example:

10 12 11  9  7  8
13 18 17  6  1  2
14 15 16  5  4  3
 9  7  8 10 12 11
 6  1  2 13 18 17
 5  4  3 14 15 16