C+
C NAME:
C	darkr
C PURPOSE:
C	To determine the dark current - this is removed from each data frame
C	Note the dark current, to be distinguished from "pedestal" is determined
C	from "covered pixels", not "empty pixels".
C CATEGORY:
C	Data processing
C CALLING SEQUENCE:
C	call darkr(mode,ic,ifm,id,jd,iframemask,frame,dark)
C INPUTS:
C	mode		   integer	1 - "Engineering" frame records, no onboard binning
C					2 - "Hi-res" frame records, binned 2 x 2 pixels
C					4 - "Normal Data" frame records, binned 4 x 4 pixels
C	ic		   integer	Camera 0,1,2, or 3
C	ifm		   integer	frame mask mode - 0 mask not imposed, 1 frame mask imposed
C	id		   integer	data frame max x-value (along rows)
C	jd		   integer	data frame max y-value (down columns)
C	iframemask(id,jd)  integer	data mask - 0 data are invalid 1 data are valid
C	frame(id,jd)   	   real		data frame that needs to have its pedestal removed
C OUTPUTS:
C	frame(id,jd)   	   real		data frame that now has its pedestal removed
C	dark		   real		Dark current value removed from the data frame
C CALLS:
C PROCEDURE:
C	Uses covered pixels to determine the dark current
C	The first row is skipped for RAL (600 rows) data
C MODIFICATION HISTORY:
C	Dec, 2002 B. Jackson (UCSD), Jan, 2003 A. Buffington (UCSD)
C	Feb, 2003 A. Smith (UCSD)
C-
c	Here we have introduced the convention [i,j]= along [rows,columns], to render
c	compatible with the convention in C. Let i always here be the "inner loop".
c
	subroutine darkr(mode,ic,ifm,id,jd,iframemask,frame,dark,idarkcr)

	real*4		frame(id,jd),dark,darkcnt,crmin
	integer*4	i,j,id,jd, idarkcr,ibad
	integer*4       iframemask(jd,id)
	data crmin / 27.78 / 	!500 electron threshold
c	data crmin / 11.11 /	!200 electron threshold
c
	darkcnt = 0.0
	dark=0.0
	idarkcr=0

	if(mode.eq.1.and.ic.eq.0) then
C
C	  Remove the known dark current from the data frame in Engineering mode for Camera 0 (RAL data format)
C	  Here id = 1280 and jd = 600
C
	  do j=2,600
	    do i=1266,1269		!These limits are compatible with those below
	      dark = dark + frame(i,j)
	      darkcnt = darkcnt + 1.0
	    end do
	    do i=18,21			!These limits are compatible with those below
	      dark = dark + frame(i,j)
	      darkcnt = darkcnt + 1.0
	    end do
	  end do
	end if
C
	if(mode.eq.2.and.ic.eq.0) then
C
C	  Remove the known dark current from the 2 by 2 pixel binning mode, Camera 0
C
c	(This depends upon how the camera 0 data get binned...)
	end if
C
	if(mode.eq.4.and.ic.eq.0) then
C
C	  Remove the known dark current from the 4 by 4 pixel binning mode, Camera 0
C
c	(This depends upon how the camera 0 data get binned...)
	end if
C
	if(mode.eq.1.and.ic.ge.1) then
C
C	  Remove the known dark current from the data frame in Engineering mode for Flight Cameras (GSE format)
C
C	  Here id = 1272 and jd = 256; this rectangle is shifted relative to Camera 0 (RAL format)
C	  by +1 pixel in i, and in j by +61, +55, and +57 rows respectively for Cameras 1, 2, and 3
C
	  do j=1,256
	    do i=1265,1268
	      ibad=0
	      if(frame(i,j).ge.crmin)ibad=1
	      if(ibad.eq.0)then
	        dark = dark + frame(i,j)
	        darkcnt = darkcnt + 1.0
	      else
	        idarkcr=idarkcr+1
c	        jarg=1+nint(4.0*4.5*frame(i,j)/50.)	!50 electron bins
c	        if(jarg.gt.250)jarg=250
c	        print 1000,i,j,frame(i,j)
c	        ihist(jarg)=ihist(jarg)+1
	      endif
	    end do
	    do i=17,20
	      ibad=0
	      if(frame(i,j).ge.crmin)ibad=1
	      if(ibad.eq.0)then
	        dark = dark + frame(i,j)
	        darkcnt = darkcnt + 1.0
	      else
	        idarkcr=idarkcr+1
c	        jarg=1+nint(4.0*4.5*frame(i,j)/50.)	!50 electron bins
c	        if(jarg.gt.250)jarg=250
c	        print 1000,i,j,frame(i,j)
c	        ihist(jarg)=ihist(jarg)+1
	      endif
	    end do
	  end do
	endif
C

	if(mode.eq.2.and.ic.ge.1) then

C	Remove the known dark current from the 2 by 2 pixel binning mode for Flight Cameras (presumed format)
C	  Here id = 636 and jd = 128
c	  This quick version, iframemask disabled
C
	  do j=1,128
	    do i=633,634
	      ibad=0
	      if(frame(i,j).ge.crmin)ibad=1
	      if(ibad.eq.0)then
	        dark = dark + frame(i,j)
	        darkcnt = darkcnt + 1.0
	      else
	        idarkcr=idarkcr+1
c	        jarg=1+nint(4.0*4.5*frame(i,j)/50.)	!50 electron bins
c	        if(jarg.gt.250)jarg=250
c	        print 1000,i,j,frame(i,j)
1000	format('Cosmic ray in covered pixel at ',2i4,', ',f6.0,' ADUs')
c	        ihist(jarg)=ihist(jarg)+1
	      endif
	    end do
	    do i=9,10
	      ibad=0
	      if(frame(i,j).ge.crmin)ibad=1
	      if(ibad.eq.0)then
	        dark = dark + frame(i,j)
	        darkcnt = darkcnt + 1.0
	      else
	        idarkcr=idarkcr+1
c	        print 1000,i,j,frame(i,j)
	      endif
	    end do
	  end do
	endif
C
	if(mode.eq.4.and.ic.ge.1) then
C
C	  Remove the known dark current from the 4 by 4 pixel binning mode for Flight Cameras (presumed format)
C	  Here id = 318 and jd = 64
C
	  do j=1,64
	    do i=317,317
	      dark = dark + frame(i,j)
	      darkcnt = darkcnt + 1.0
	    end do
	    do i=5,5
	      dark = dark + frame(i,j)
	      darkcnt = darkcnt + 1.0
	    end do
	  end do
	end if
c
	if(darkcnt.eq.0)then
		print *,"No dark current: mode, ic = ",mode,ic
		return
	endif
c
	dark=dark/darkcnt
c
	if(ifm.eq.0)then
	  do j=1,jd
	    do i=1,id
	      if(frame(i,j).gt.0.)frame(i,j) = frame(i,j) - dark
	    end do
	  end do
	else
	  do j=1,jd
	    do i=1,id
	      if(iframemask(i,j).ne.0.and.frame(i,j).gt.0.)frame(i,j) = frame(i,j) - dark
	    end do
	  end do
	endif

	return
	end