iprfile=replicate(0.,256,5)
c='0'
for j=0,2 do begin
    f=string(j,form='(i1)')
    openr,u,'save/941018'+c+f+'.ray',/get
    fs=FSTAT(u)
    nim=fs.SIZE/66048L
    PRINT,j,nim
    a=assoc(u,bytarr(66048L))
    sumarr=replicate(0.,256)
    for k=0,nim-1 do begin
	b=a(k)
        h=byte(b,0,512)
        f=fix(h(290))
        if h(291) eq 1 then f=2^f
        im=fix(byte(b,512,256,256))*f
	sumarr=sumarr+im(*,135)/float(im(166,135))
	ENDFOR
    iprfile(0,j)=sumarr/nim
    free_lun,u
    endfor
contour,iprfile(160:179,*),indgen(20)+160,indgen(5),/follow
end