Newsgroups: sci.image.processing
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From: perry@netcom.com (Perry West)
Subject: Re: The term "pixel" and multispectral data
Message-ID: <perryD28yp7.20C@netcom.com>
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References: <alanf.789781646@bruce.cs.monash.edu.au>
Date: Wed, 11 Jan 1995 15:22:19 GMT
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I always believed pixels could be multi-valued, and that single valued 
pixels (e.g., gray-scale) was just a limited case of multi-valued.

I am not comfortable with the idea of limiting a pixel to be only a 
single plane or band because, as was pointed out, things arn't this 
constant.  Very often we translate RGB into HSI and drop the S (maybe 
also drop the I).  Sometimes we can go the other way -- process an image 
with the Sobel operator to extract gradient magnitude and direction -- 
going from a single valued pixel to a multi-valued pixel.

I have always viewed the pixel as the *atom* of an image in the sense you 
cannot divide it (spatially).  However, with processing, its value or 
contents can be modified.

