Subject: combining FITS images

From: bourke at cfaprotostar.harvard.edu (Tyler Bourke)
Date: Tue, 21 Feb 1995 22:01:40 GMT

Is it possible to combine 3 grey scale FITS images into one 3 colour FITS image
(or any other format such as postscript, jpeg etc)?  I would like to combine
J, H and K images into a colour image, J=blue etc.

If not, is it possible to turn the FITS images into another format which will allow
me to do this (if so, how).

Thanks in advance

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From: adam at csi.jpl.nasa.gov (Adam Bernstein)
Date: 22 Feb 1995 22:28:02 GMT

In article <D4DEIt.MFD at cfanews.harvard.edu>, bourke at cfaprotostar.harvard.edu (Tyler Bourke) writes:
|> Is it possible to combine 3 grey scale FITS images into one 3 colour FITS image
|> (or any other format such as postscript, jpeg etc)?  I would like to combine
|> J, H and K images into a colour image, J=blue etc.
|> 
|> If not, is it possible to turn the FITS images into another format which will allow
|> me to do this (if so, how).
|> 

	You can, more or less, do this using IRAF.  If you have a spiffy
24-bit display, you can really do it (using the 'images.tv.iis' tasks, 
specifically 'rgb'), or you can do an 8-bit approximation using the 
add-on external package called 'color', obtainable from the IRAF archives.
First, of course, you have to read the FITS images into native IRAF format.

	Don't know another way to do it more directly, but perhaps someone
else does.

		Adam

-- 
-------------------------------------------------------------
Adam Bernstein                           Jet Propulsion Lab
Avionic Equipment Section,               MS 198-235
  Optical Tracking Group                 4800 Oak Grove Dr.
http://dragon.jpl.nasa.gov/~adam/        Pasadena, CA 91109
adam at dragon.jpl.nasa.gov                 Phone: 818 354-0783
  or adam.c.bernstein at jpl.nasa.gov       FAX:   818 393-6105
-------------------------------------------------------------

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From: fitz at noao.edu (Mike Fitzpatrick)
Date: 22 Feb 1995 22:37:37 -0700

> First, of course, you have to read the FITS images into native IRAF format.

	IRAF V2.11 will include a FITS image kernel so converting the FITS
files won't strictly be necessary then.  V2.11 will also include two new 
tasks for image conversion (these are available now in an external package
called IMCNV, see ftp://iraf.noao.edu/iraf/extern/imcnv.tar.Z) that will
allow you to convert IRAF images (or FITS in this case) to some other format
(EPS, GIF, rasterfiles, others) directly.  Using the EXPORT task you can
create e.g. a 24-bit rasterfile that combines your three input images, you
can also use the same colormap generation algorithm as in the COLOR package
to create an 8-bit colormapped image.  Color EPS is supported and the task
provides a general arithmetic expression evaluator so input images may be
combined as mosaics and intensity values can be mapped to 8-bit in a number
of ways.  For formats that aren't currently supported (e.g. JPEG and TIFF)
you can write out something like GIF and convert using some other utility.
The IMPORT task allows you to convert other formats into IRAF images.
	This package is available on a test-release basis now, if you find 
any bugs or have any questions or suggestions let me know.  

Mike Fitzpatrick
NOAO/IRAF Group
fitz at noao.edu