;------------------------------------------------------------------
;+
; NAME:
;	DMGSETUP
; PURPOSE:
;	This procedure accepts a BBSO DMG FITS file.
;	A flat-field magnetogram generated from Jongchul Chae's
;	vmg_flat procedure is subtracted from the magnetogram
;	to remove large-scale non-uniformities in the magnetogram.
;       A V (really scaled V/I) and total I image are generated.
;       This version does not rebin the pixels since the DMG
;       pixels are already square.  The images are returned as viss
;       and jiss (for compatibility).
;
;	Note that the old IRAF version deleted the original FITS
;	files.  This version does not.
;
;	Note that the old version (using the boxcar smoothing)
;	did not scale the VMG image when it was loaded.  This
;	version does.
; CATEGORY:
;	POLAR
; CALLING SEQUENCE:
;	DMGSETUP,vfile,vih,viss,jiss,flatfile,jflat,jdark
; INPUTS:
;	vfile = file name for input magnetogram (FITS format).
;	flatfile = IDL variable containing VMG flatfield image.
;       jflat = IDL variable containing J flatfield image.
;       jdark = IDL variable containing a dark frame with same number
;               of frames as vfile
; KEYWORD PARAMETERS:
; OUTPUTS:
;	vo = IDL variable containing "flattened" magnetogram
;	jo = IDL variable containing flattened direct image
; COMMON BLOCKS:
; NOTES:
; MODIFICATION HISTORY:
;       J. Varsik,      09 Nov. 1999 --- Port from lcsetup.pro.
;-
;-------------------------------------------------------------------

pro dmgsetup,vfinam,vih,vo,jo,ffimg,jfimg

    ; Display IDL header if help is required.
    if (keyword_set(help)) then begin
      get_idlhdr,'dmgsetup.pro'
      goto,finishup
    endif

    k1 = 14500.0

    ; Read V file
    vi = READFITS(vfinam,vih)
    vx = (FLOAT(vi(*,*,0)) - FLOAT(vi(*,*,1)))/ $
         (FLOAT(vi(*,*,0))+FLOAT(vi(*,*,1)) - jdark)
    vx = k1 * vx
    vo = vx - ffimg
 
    ; Normalize J flat
    jmean = mean(jfimg)
    jn = jfimg / jmean

    ; Read J file
    jx = FLOAT(vi(*,*,0)) + FLOAT(vi(*,*,1))
    jx = jx - jdark
    nz = where(jx ne 0.)
    z = where(jx eq 0., numzeros)

    if (numzeros gt 0) then begin
	jo(nz) = jx(nz) / jn(nz)
        jo(z) = 0.
    endif else begin
	jo = jx / jn
    endelse

    finishup:

    return
end