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From: ken@turtlevax.UUCP (Ken Turkowski)
Newsgroups: net.graphics
Subject: Re: Allocation of color map
Message-ID: <785@turtlevax.UUCP>
Date: Mon, 10-Jun-85 14:23:09 EDT
Article-I.D.: turtleva.785
Posted: Mon Jun 10 14:23:09 1985
Date-Received: Tue, 11-Jun-85 07:24:26 EDT
References: <12800001@umn-cs.UUCP>
Reply-To: ken@turtlevax.UUCP (Ken Turkowski)
Organization: CADLINC, Inc. @ Menlo Park, CA
Lines: 21

In article <12800001@umn-cs.UUCP> bolte@umn-cs.UUCP writes:
>	I am doing some ray tracing as an independent study project and 
>have run up against a brick wall. The problem is allocating the color
>lookup map (8 bits deep) properly to match whatever distribution of colors
>result from any single run. I would appreciate either algorithms other people
>have worked out or a reference to a paper on the topic.

There was a paper in the February 1984 issue of IEEE Computer Graphics
and Applications by A.F. Lehar and R.J. Stevens called "High-Speed
Manipulation of the Color Chromaticity of Digital Images".  It scans
the 3-dimensional color space with a Peano curve, yielding a
1-dimensional signal that is trivial to cluster for quantization
purposes.  While suboptimal, it is very fast and quite produces
remarkable results.  If the quantization isn't quite good enough, it
can be used as the starting point of an iterative optimal clustering
procedure.
-- 

Ken Turkowski @ CADLINC, Menlo Park, CA
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