openw,99,'image1.dat'
reads,'w0b16105b.d0h',a,nx,ny,0
tvwindow,0,xs=nx,ys=ny
tv,a
print,' Input center coordinates'
tvrdc,x,y,/dev
print,'center=',x,y
printf,99,'center=',x,y
b=a(x-127:x+128,y-127:y+128)*1.
back=fltarr(4)
for i=0,3 do begin
   print,' Input background coordinates (cr to continue)',i
   cr=' ' & read,cr &   tvrdc,x,y,/dev
   back(i)=median(a(x-4:x+5,y-4:y+5))
   printf,99,'coordinates,background=',x,y,back(i)
endfor
print,'back=',back
b=b-total(back)/4.
b=b/total(b)
;
; Cosmic ray removal
;
mask=where((abs(b-smooth(b,2)) gt 0.4*b) and (b gt 9.e-5))
b(mask)=0
sm=smooth(b,3)
b(mask)=sm(mask)
for i=0,4 do b(where(b eq max(b)))=0.
b=b/total(b)
writes,'image1',b
close,99
stop
end