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Re: Q: about Richardson_Lucy Alg. (deconvolution)



In article <7mlo5n$pps$1@sylvester.vcn.bc.ca>,
  "Herbert H. Tsang" <tsang@vcn.bc.ca> wrote:
>
> Anyone is familiar w/ the Richardson_Lucy Deconvolution alg.? I have
found
> a IDL program (lucy_guess.pro) that claims to perform this
deconvolution.
>
> However, when examining the code I am not quite sure if it is correct.
 in
> lucy_guess.pro line 89 it has this loop
> 	for k=0,n_iter do begin
> 	    weight = convol(old,psfr)
> 	    new	   = old * convol( (data/weight) ,psf)
> 	    old    = new
> 	endfor
>
> but shouldn't it be
>         for k=0,n_iter do begin
>             weight = convol(old,psfr,/edge_truncate)
>             new    = old * correlate( (data/weight) ,psf)
>             old    = new
>         endfor
>
> Any idea??

You are correct about the correlation step: the inner operation is a
convolution used to simulate the imaging process; the outer operation is
a correlation. Whether to use /EDGE_TRUNCATE or not is up to the user.

Ed Meinel


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