Name

---

      FITSRGB_to_TIFF

Purpose

---

      Combine separate red, green, and blue FITS images into TIFF format

Explanation

---

      The output TIFF (class R) file can have colors interleaved either
      by pixel or image. The colour mix is also adjustable.

Calling Sequence

---

      FITSRGB_to_TIFF, path, rgb_files, tiff_name [,/BY_PIXEL, /PREVIEW,
                        RED= , GREEN =, BLUE =]

Inputs

---

      path = file system directory path to the RGB files required.
      rgb_files = string array with three components - the red FITS file
                  filename, the blue FITS file filename and the green FITS
                  file filename

Outputs

---

      tiff_name = string containing name of tiff file to be produced

Optional Output

---

      Header = String array containing the header from the FITS file.

Optional Input Keywords

---

      BY_PIXEL = This causes TIFF file RGB to be interleaved by pixel
                  rather than the default of by image.
      PREVIEW = Allows a 24 bit image to be displayed on the screen
                  to check the colour mix.
      RED = Real number containing the fractional mix of red
      GREEN = Real number containing the fractional mix of green
      BLUE = Real number containing the fractional mix of blue

Example

---

      Read three FITS files, 'red.fits', 'blue.fits' and 'green.fits' from
      the directory '/data/images/space' and output a TIFF file named
      'colour.tiff'
              IDL> FITSRGB_to_TIFF, '/data/images/space', ['red.fits', $
                    'blue.fits', 'green.fits'], 'colour.tiff'
      Read three FITS files, 'red.fits', 'blue.fits' and 'green.fits' from
      the current directory and output a TIFF file named '/images/out.tiff'
      In this case, the red image is twice as strong as the green and the
      blue is a third more intense. A preview on screen is also wanted.
              IDL> FITSRGB_to_TIFF, '.', ['red.fits', $
                    'blue.fits', 'green.fits'], '/images/out.tiff', $
                    /PREVIEW, RED=0.5, GREEN=1.0, BLUE=0.666

Restrictions

---

      (1) Limited to the ability of the routine READFITS

Notes

---

      None

Procedures Used

---

    Functions: READFITS, CONCAT_DIR
    Procedures: WRITE_TIFF

Modification History

---

    16th January 1995 - Written by Carl Shaw, Queen's University Belfast
27 Jan 1995 - W. Landsman, Add CONCAT_DIR for VMS, Windows compatibility
Converted to IDL V5.0 W. Landsman September 1997
    Use WRITE_TIFF instead of obsolete TIFF_WRITE W. Landsman December 1998
    Cosmetic changes W. Landsman February 2000