;--------------------------------------------------------------
;Motivation：
;   cheking and fixing the invalid pixels
;Input:
;   InputPath-end with '\'
;   InputName
;   Outpath
;Output:
;   new file of wich the invalid pixels are fixed 
;   the new filename is suffixed with '_IvdPxl' after the origin filename
;Created by ShuaiTong 2011.06.09
;   
;--------------------------------------------------------------

pro InvalidPixel,InputPath,InputName,OutPath

  ;Input
;  InputPath='D:\results\moon\Copernicus\'
;  InputName='CE1_BMYK_IIM_XXX_2874_B_reflectance_correct_validB_MNF_IvdLine.img';
;  OutPath=InputPath
  OutName=file_basename(InputName,'.img')+'_IvdPxl.img'
  file=InputPath+InputName
  tp=2;max threshold for invalid pixel; tp=2

  ;open file
  ENVI_OPEN_FILE,file,r_fid=fid
  ENVI_FILE_QUERY,fid,ns=ns,nl=nl,nb=nb,dims=dims

  band=fltarr(ns,nl);存放波段数组
  bGrads=fltarr(ns,nl);存放梯度
  bGrads1=fltarr(ns,nl);存放梯度分子
  bGrads2=fltarr(ns,nl);存放梯度分母
  bandNew=fltarr(ns,nl,nb);存放修复后的数据

  for b=0,nb-1 do begin 
    band=ENVI_GET_DATA(fid=fid,dims=dims,pos=b)
    bandNew[*,*,b]=band
    ;computing grads
    for s=1,ns-2 do begin
      bGrads1[s,*]=band[s-1,*]+band[s+1,*]-2*band[s,*]
      bGrads2[s,*]=band[s-1,*]+band[s+1,*]
    endfor
    for l=1,nl-2 do begin
      bGrads1[*,l]=bGrads1[*,l]+band[*,l-1]+band[*,l+1]-2*band[*,l]
      bGrads2[*,l]=bGrads2[*,l]+band[*,l-1]+band[*,l+1]
    endfor
    bGrads[1:ns-2,1:nl-2]=abs(bGrads1[1:ns-2,1:nl-2]/bGrads2[1:ns-2,1:nl-2]*4)
;   print,bGrads[*,636]
    
    ;Invalid pixels locations
    index=where(bGrads gt tp,count)
;    print,'band',b+1,',',count,' invalid pixels'
    linePositon=where(bGrads gt tp)/ns
    samplePosition=where(bGrads gt tp) mod ns
;    print,'line  ',linePositon
;    print,'sample',samplePosition
  
    ; Fixing invalid pixels
    for icount=0,count-1 do begin
      lp=linePositon[icount]
      sp=samplePosition[icount]
      bandNew[sp,lp,b]=(bandNew[sp+1,lp,b] + bandNew[sp-1,lp,b] + bandNew[sp,lp+1,b] + bandNew[sp,lp-1,b])/4
;      print,'fix pixel:line',lp,',sample',sp
    endfor

;    print,'--------------------------------------------------'
  endfor

  ;output file
  ENVI_WRITE_ENVI_FILE, bandNew, out_name=OutPath+OutName,r_fid=r_fid
  print, OutPath, OutName, '. is over!'
  envi_file_mng, id=fid, /remove; , /delete   
  envi_file_mng, id=r_fid, /remove
end