pro autocorr, img, ns, nl, out

xmove=min([ns-1,100])
ymove=min([nl-1,100])
 
data=fltarr(ns, nl,/nozero)

openr, un, /get, img
readu, un, data
close, un

openw, un, out

index=where(data ne 0)
data(index)=data(index)+0.5
data=byte(data*255)

for i=0,xmove do begin
for j=0,ymove do begin
	fixed=data(0:ns-i-1,0:nl-j-1)
	moved=data(i:ns-1,j:nl-1)
	index=where(moved ne 0 and fixed ne 0)

;	print, size(index)
;	print, (size(moved))(1)- (size(fixed))(1), (size(moved))(2)-(size(fixed))(2)
	res=correlate(fixed(index), moved(index));
	print, res, size(moved), i, j
	writeu, un, res

endfor
endfor

close, un
free_lun, un

end