Path: news.mathworks.com!not-for-mail
From: "Vihang Patil" <vihang_patil@yahoo.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: machine vision-Color Matching
Date: Tue, 4 Mar 2008 05:04:57 +0000 (UTC)
Organization: Konem Solutions
Lines: 36
Message-ID: <fqil9p$kvg$1@fred.mathworks.com>
References: <fpgn52$9ij$1@fred.mathworks.com> <fqh5js$if5$1@fred.mathworks.com>
Reply-To: "Vihang Patil" <vihang_patil@yahoo.com>
NNTP-Posting-Host: webapp-05-blr.mathworks.com
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
X-Trace: fred.mathworks.com 1204607097 21488 172.30.248.35 (4 Mar 2008 05:04:57 GMT)
X-Complaints-To: news@mathworks.com
NNTP-Posting-Date: Tue, 4 Mar 2008 05:04:57 +0000 (UTC)
X-Newsreader: MATLAB Central Newsreader 413701
Xref: news.mathworks.com comp.soft-sys.matlab:455172


"Ethan " <emontag.nospam@leuzeusa.com> wrote in message 
<fqh5js$if5$1@fred.mathworks.com>...
> You are trying to use one number to represent color when 
you need more. 
> You should read a little bit about color to understand 
the problem, but 
> basically your colors are going to vary in 3 dimensions, 
so you should check 
> color in 3 dimensions. If you have an issue with color 
tolerance, ie not all 
> blues are the same blue - they have some variation that 
is tolerable, then you 
> may need to go deeper into understanding color. 
Otherwise you can try 
> looking at the distance in 3D of a measured color from 
the standard color 
> (say in rgb) rather than the sum of the color 
coordinates. You can also 
> simplify things a little by using reducing the color to 
2 dimensions by 
> normalizing (into an analog of chromaticity). That is, 
use r=R/(R+G+B), 
> g=G/(R+G+B) where R, G, and B are the digital values and 
r and g are 
> "chromaticities". Then you may be able to use 2D 
distances instead of 3D. But 
> if real color is important, you may need to use a real 
color space that is 
> associated with human color vision.
> 
>
Hello Ethan
Could you please point out to some website/reference book 
that would give insights on this 3D color space 
representation and analysis. That would really be helpful
Vihang