raja@bombay.cps.msu.edu (Narayan S. Raja) (01/11/91)
Archive-name: graphics/pixutils/fbm/1991-01-10
Archive: nl.cs.cmu.edu:/usr/mlm/ftp/fbm.tar.Z [128.2.222.56]
Original-posting-by: raja@bombay.cps.msu.edu (Narayan S. Raja)
Original-subject: Re: How do I separate color images into RGB channels.
Reposted-by: emv@ox.com (Edward Vielmetti)
In article <651@ub.d.umn.edu>, (Haseen I. Alam) writes:
< I need to get hold of some programs that will run in SunTools, and will
< allow me to separate a color image into its RGB channels and display them
< separately. It will be nice if it will recombine them again.
Get Michael Mauldin's "FBM" set of utilities:
available by anonymous ftp from the "/usr/mlm/ftp"
subdirectory on nl.cs.cmu.edu (128.2.222.56).
(You can only cd straight to that directory).
The FBM utilities are independent of your windowing
environment. I assume you want to work with 8-bit
colour Sunraster files.
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Going from 8-bit colour to the 3 colour planes is
easy:
cat image.ras | clr2gray -S -r1 > image.red.ras
cat image.ras | clr2gray -S -g1 > image.grn.ras
cat image.ras | clr2gray -S -b1 > image.blu.ras
(The 3 colour planes are themselves extracted as
Sun grayscale rasterfiles).
Going from 3 colour planes back to an 8-bit colour
image is somewhat painful (anyone know a better way?):
1. remember the number of rows and columns
2. strip off the header by some means, leaving
3 "raw" images (just the bytes, no header)
3. concatenate these raw files in the order r,g,b:
cat image.red.raw image.grn.raw image.blu.raw > image.raw
4. convert to fbm format:
raw2fbm -d3 -hrows -wcols < image.raw > image.fbm
where rows=no. of rows, cols=no. of columns
5. quantize to 8 bits:
fbquant -S < image.fbm > image.8-bit-ras
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Narayan Sriranga Raja.