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From: wong@ICS.UCI.EDU (Wang-chan Wong)
Newsgroups: comp.graphics
Subject: RGB -> 16 grayscale
Message-ID: <5083.669373541@ics.uci.edu>
Date: 19 Mar 91 09:08:10 GMT
Lines: 14

Hi,  I am working on a project that requires to display 256 colors with
a 16 levels grayscale (as with a gas plasma screen.)  I understand
that the following formula will compute the corresponding of graylevel
given the rgb intensity:

    grayscale= .299*red+ .587*green + .114*blue

However, given 256 colors, this formula still maps onto more than 16
distinct grayscales.  My question is: how to map exactly onto 16
grayscales?  Are there any algorithms that map onto 16 grayscales
while minimizing color collison at the same time? (i.e. I can still
view a 256 pictures in the 16 grayscales gas plasma screen.)

Thanks in advance.   -- wang