Newsgroups: sci.image.processing
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From: chengwu@sciborg.uwaterloo.ca (Chengwu Cui)
Subject: Re: Visible Color Definitions?
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References: <95191.163347MCOAN41@maine.maine.edu>
Date: Tue, 11 Jul 1995 15:08:43 GMT
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In article <95191.163347MCOAN41@maine.maine.edu>,
 <MCOAN41@MAINE.MAINE.EDU> wrote:
>(Suggestions on more appropriate newsgroups for this post are wel-
>comed.)
>
>I'm beginning work on leaf reflectances, using a spectrophotometer.
>What has me stumped is finding any reference to colors in the vis-
>ible band, defined in nm. What is green, green/yellow, yellow, and
>so on? I just want to use some accepted definitions when I analyse
>the data... anyone have pointers to a source of this info?
>
>All I've found are vague references to UV versus visible versus IR,
>or the visible as just blue, green, red. What I'd like to find is
>the entire visble spectrum defined, by precise color names and
>wavebands.
>
>Is there a good reason why I can't find one? Or am I just over-
>looking something obvious, as usual. If anyone is able to give
>info in any direction, I'd appreciate hearing it.

Stuff from psychophysical experiments fall in fuzzy sets by nature. 
Standards are therefore difficlut to come. You may have to define 
that by  yourself for your specific application say, colors of leaves 
depending how fine do you want your system to be. 
Note that the same spectral distributions always have the same color, but 
not vice versa. Therefore, you may need to calculate Tristimulus 
value and then try to convert the values into hue angle as  proposed by 
CIE.Hope this helps.
Chengwu     

>
>Thanks.
>
>-- Mike Coan
>mcoan@grouse.spatial.maine.edu


