pro calibrate,image,ns,nl

;dir='a'
;read, dir, prompt='What directory  '

;cd, dir
;$cp *.hdr /photon/data1/temp
openr, 1,image

;cd, '/photon/data1/temp'
output=strcompress(image+'.cal')
openw, 2, output

fline=fltarr(ns)
line=bytarr(ns)

calcoeffs96=[.00129,.00273,.00201,.0031,.00213,.00251]
caloffsets96=[.036,.031,.029,-.018,-.003,.054]

darksub=bytarr(6)
year=1996
ncoeff=fltarr(6)
noffset=fltarr(6)

read, darksub1,prompt='Darksub 1   '
read, darksub2,prompt='Darksub 2   '
read, darksub3,prompt='Darksub 3   '
read, darksub4,prompt='Darksub 4   '

darksub(0)=darksub1
darksub(1)=darksub2
darksub(2)=darksub3
darksub(3)=darksub4

read, year, prompt='What year   '

if (year ne 1996) then begin
 
 for i=0,5 do begin
   read, ncoeff1,prompt='Normalization coeff  '
   ncoeff(i)=ncoeff1
 endfor

 for i=0,5 do begin
   read, noffset1,prompt='Normalization offset  '
   noffset(i)=noffset1
 endfor

endif


for j=0,5 do begin
;      if (j eq 5) then point_lun, 1, float(ns)*float(nl)*6.0
      print, 'band',j

      for i=0,nl-1 do begin

      readu,1,line

      index=where(line le 0, count)
      fline=float(line)
      fline=fline-darksub(j)
      
      index2=where(line ne 0,count2)

       if ((year ne 1996) and (count2 gt 0)) then $
         fline(index2)=fline(index2)*ncoeff(j)+noffset(j)
      
       if (count2 gt 0) then $
          fline(index2)=fline(index2)*calcoeffs96(j)+caloffsets96(j)

      
      if (count gt 0) then fline(index)=0

       writeu, 2, fline

       endfor
endfor

free_lun, 1,2

end