C+
C NAME:
C	lsff
C PURPOSE:
C	To remove the baseline large scale flat field from the data frames
C CATEGORY:
C	Data processing
C CALLING SEQUENCE:
C	call lsff(mode,ic,ifm,id,jd,iframemask,framelsff,frame)
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 0,1,2,3 or 4
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 showing location of valid data
C	framelsff	   real		Baseline large scale flat field 
C	frame(id,jd)	   real		Data frame from CCD
C OUTPUTS:
C	frame(id,jd)	   real		Data frame from CCD, the known lsff having been applied
C CALLS:
C	none
C PROCEDURE:
C	The baseline flatfield correction is here imposed upon the data
C	Updates to this flatfield are applied by program "lsffu.f" until these have become incorporated
C	into the framelsff as a "new baseline".
C MODIFICATION HISTORY:
C	Jan. 2003, A. Buffington (UCSD)
C-
	subroutine lsff(mode,ic,ifm,id,jd,iframemask,framelsff,frame)
c
	real		framelsff(1280,600),
     &			frame(id,jd)
     
	integer 	iframemask(id,jd)
	integer*4	ii,jj
C
C	Remove the ground-based large scale flat field from the data in the Engineering mode.
C
	if(mode.eq.1) then
	  do j=1,jd
	    do i=1,id
		if(iframemask(i,j).ne.0) then
		    frame(i,j) = frame(i,j)/framelsff(i,j)
		end if
	    end do
	  end do
	end if
C
C	Remove the ground-based large scale flat field from data in the 2 x 2 binning mode.
C
	if(mode.eq.2) then
	  do j=1,jd
	    jj=1+(j-1)/2
	    do i=1,id
	        ii=1+i/2
		if(iframemask(i,j).ne.0) then
		    frame(i,j) = frame(i,j)/framelsff(ii,jj)
		end if
	    end do
	  end do
	end if
C
C	Remove the ground-based large scale flat field from data in the 4 x 4 binning mode.
C
	if(mode.eq.4) then
	  do j=1,jd
	    jj=1+(j-1)/4
	    do i=1,id
	        ii=1+i/4
		if(iframemask(i,j).ne.0) then
		    frame(i,j) = frame(i,j)/framelsff(ii,jj)
		end if
	    end do
	  end do
	end if
C
	return
	end