PRO decheck, ch8

; decheckerboard white light channel
; average over existing nearest neighbors

dummy = SIZE(ch8) ; get size and # frames
size1 = dummy(1) & size2=dummy(2)
if ((size1 eq 1) or (size2 eq 1)) then return
n_frames = 1
IF dummy(0) eq 3 THEN n_frames = dummy(3)

FOR n = 0, n_frames-1 DO BEGIN
dummy = FLTARR(size1+2,size2+2)
dummy(1,1) = ch8(*,*,n)
dummy(1,0) = ch8(*,1,n)
dummy(1,size2+1) = ch8(*,size2-2,n)
dummy(0,1) = ch8(1,*,n)
dummy(size1+1,1) = ch8(size1-2,*,n)
FOR i = 1, size1 DO FOR j = 1, size2 DO IF dummy(i,j) eq 0 THEN $
  dummy(i,j) = ( dummy(i,j+1) + dummy(i,j-1) + dummy(i+1,j) + dummy(i-1,j) )/4.
ch8(0,0,n) = dummy(1:size1,1:size2)
ENDFOR

RETURN
END