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From: markwr@aisb.ed.ac.uk (Mark Wright)
Subject: Skeletonisation/distance transform technical report
Message-ID: <Cz21Hv.JuC@aisb.ed.ac.uk>
Keywords: skeletonisation, distance transformation, singularity theory
Sender: news@aisb.ed.ac.uk (Network News Administrator)
Reply-To: markwr@aisb.ed.ac.uk (Mark Wright)
Organization: Dept of AI, University of Edinburgh, Scotland
References: <1994Nov9.001944.5633@rp.CSIRO.AU> <39s43k$65r@fang.dsto.gov.au>
Date: Thu, 10 Nov 1994 13:58:43 GMT
Lines: 67

The following technical report is available by anonymous ftp from the
archive of the Speech, Vision and Robotics Group at the Cambridge
University Engineering Department.


                   Skeletonisation using an extended 
                      Euclidean distance transform

                   Mark W. Wright, Roberto Cipolla
                        and Peter J. Giblin

                   Technical Report CUED/F-INFENG/TR196

                   Cambridge University Engineering Department 
                           Trumpington Street 
                           Cambridge CB2 1PZ 
			     England 


                             Abstract

A standard method to perform skeletonisation is to use
a distance transform. Unfortunately such an approach has the drawback
that only the Symmetric axis transform can be computed and not
the more practical smoothed local symmetries or the more
general symmetry set. Using singularity theory we introduce an
extended distance transform which may be used to capture more of the
symmetries of a shape. We describe the relationship of this extended
distance transform to the skeletal shape descriptors themselves and
other geometric phenomena related to the boundary of the curve. We
then show how the extended distance transform can be used to derive
skeletal descriptions of an object.

Keywords: Symmetry, Skeleton, Distance transform, Singularity theory
               

************************ How to obtain a copy ************************

a) Via FTP:

unix> ftp svr-ftp.eng.cam.ac.uk
Name: anonymous
Password: (type your email address)
ftp> cd reports
ftp> binary
ftp> get wright_tr196.ps.Z
ftp> quit
unix> uncompress wright_tr196.ps.Z
unix> lpr wright_tr196.ps (or however you print PostScript)

b) Via postal mail:

Request a hardcopy from

Mark W. Wright
Department of Artificial Intelligence
University of Edinburgh
5 Forrest Hill
Edinburgh
EH1 2QL
Scotland
UK
or email me: markwr@aifh.ed.ac.uk




