Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcvax!i2unix!irst!bellutta
From: bellutta@irst.UUCP (Paolo Bellutta)
Newsgroups: comp.graphics
Subject: Color Quantization
Keywords: Color, RGB, Image Processing
Message-ID: <281@irst.UUCP>
Date: 25 May 89 06:55:47 GMT
Organization: I. R. S. T. , Trento - Italy
Lines: 33


Two questions about color image processing:


First: What is the best way to compress 24 bit color images in 8 bit color
       images but using always the same colormap?  I tryed to assign 3 bits
       for red and green and 2 bits for blue but the results are not very 
       good (the image in general has a very high contrast).  

Second: I want to compute from 24 bit rgb images one image that contains
        luminance information (Y = 0.299 * R + 0.587 * G + 0.114 * B) and
        another image with chrominance information (C = R / (R + G)).
        In parentheses I wrote what I'm using. 
        I found that in general the Y image has high contrast and the C
        image has poor color resolution. I mean that if two sides of an object
        have the same color but one is too dark, on the C image it is seen
        as black.
        Are there better algorithms to use?



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I.R.S.T.
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e-mail: bellutta@irst.uucp