🚀 go-pugleaf

In article <1992Jul24.105328.1@ntuvax.ntu.ac.sg> egntoh@ntuvax.ntu.ac.sg writes:

> I would like to hv information on image restoration in the area of
> motion blurr and out_of_focus restoration. Could anyone comment on the
> availability of good papers and software? By the way. is there any ftp
> site providing softare or images on image restoration ?

The normal linear way to do this is via the cepstral filtering: linear
motion blur results in two sharp dips in the cepstrum, while defocus
blur results in the superposition of a Bessel onto the cepstrum (which
you can identify by the zero crossings).

Probably the standard papers in this area are:

@ARTICLE{Cannon,
   AUTHOR = "T. Michael Cannon",
   TITLE = "Blind Deconvolution with Spatially Invariant Image Blurs with
            Phase",
   JOURNAL = "IEEE Transactions on Acoustics, Speech, and Signal Processing",
   VOLUME = 24, NUMBER =1, PAGES = "58--63",
   YEAR = "1976",
   KEYWORDS = "enhancement, got"}

@ARTICLE{Cannon-Trussell-Hunt,
   AUTHOR = "T. Michael Cannon and H. Joel Trussell and Barry R. Hunt",
   TITLE = "A Comparison of Image Restoration Methods",
   JOURNAL = "Applied Optics", VOLUME = 17, PAGES = "3384--3390",
   YEAR = "1978",
   KEYWORDS = "enhancement, got"}

Note that cepstral filtering will result in ringing at sharp edges
(after all, you will be throwing away the high frequencies).  To do
any better than this, you have to go to non-linear techniques such as
maximum entropy (MEM) or maximum _a posteriori_ (MAP).

Hope this helps.

--
 Dr Adrian F. Clark                                   JANET: alien@uk.ac.essex
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 Dept ESE, University of Essex, Wivenhoe Park, Colchester, Essex, C04 3SQ, UK.