;----------------------------------------------------------------------
; NAME:
;	remove_pattern_spectra10micron
; PURPOSE:
;       Remove the digital noise pattern from 10 micron spectra.
;       10 micron spectra are unique becuase the cutoff on the N-band
;       filter limits light in the last channel. Thus the last channel
;       should be completely dark except for the pattern noise.
;
; EXPLANATION:
;       When called the program subracts the flux in the last channel
;       from the channels 0-14 to remove the pattern noise. The
;       pattern noise is present in each of the 16 (0-15) channels,
;       but the last channel does not detect light because the
;       transmission of the N-band filter used as a long wavelength
;       blocking element is close to zero. 
;
;       This trick ONLY works for the 10 micron grism spectra.
;       
; CALLING SEQUENCE:
;       remove_pattern_spectra10micron , imlist
;	prs10, imlist
; INPUTS:
;       imlist - a filename for a file containing a list of images
;                  that need to be pattern corrected.
;
; OPTIONAL INPUTS:
;
; OPTIONAL INPUT KEYWORDS:
;
; OUTPUTS:
;        output files will have the same image name as specified in
;        the image list but will have the prefix 'p' which stands for
;        pattern removed.
;
; OPTIONAL OUTPUTS:
;
; NOTES:
;      This procedure requires that the path name for the filelist
;      template is set to the appropriate path name. Pleas alter the
;      path name for this file accordingly.
;      
;
; PROCEDURE CALLS:
;
; REVISION HISTORY:
;-------------------------------------------------------------------------

 PRO rps10, imlist
;PRO remove_pattern_spectra10micron, imlist
; creates an array for the pattern to be subtracted. 
  pattern = dblarr(20,240)
;avgpix  an array for the average channel offsets. 
  avgpix = dblarr(15)
;an array for the new data
  newData = dblarr(320,240)

;retreive the file list.
files_file=make_array(1, /STRING)
restore, '/d1/data1/mirsi/analysis/filelist_template.idl'
;restore, '/home/mkassis/IDL_pro/filelist_template.idl'
files_file=read_ascii(imlist, template=filelist_template)
filelist=files_file.field1
nfiles=n_elements(filelist)



; loops over the number of images 
 FOR i=0, nfiles-1  DO BEGIN 
     image_name = filelist(i)  
     ;read the data
     data  = READFITS(image_name, header, EXTEN_NO=0)

     ;get the pattern noise values from the last channel
     pattern[*,*] = data[300:319,0:239]
     ;subtract the pattern from the images.  
     FOR l=0,15 DO BEGIN
         newData[l*20:l*20+19,*] = data[l*20:l*20+19,*] - pattern[*,*] 
     ENDFOR



   ; write the image to disk. The image name has a the 
   ;  prefix 'p' to designate that the image has gone 
   ;  through a Pattern removal. The fits header is updated
   ;  to reflect that the pattern was removed.

   history = 'Digital noise pattern removed for grism 10 spectra' 
   sxaddhist, history, header
   image_name = 'p' + image_name
   writefits, image_name, newData, header

ENDFOR

end