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Thinning image morphological operator

I had a question about the THIN function in IDL. I was under the
impression that this operation was supposed to preserve connectivity.
Am I mistaken? The IDL implementation does not seem to do so.

The image linked below is output from a program I wrote. It simply
takes the image on the left and applies the THIN function, yielding the
image on the right. (Note the gap that forms toward the bottom.)

http://twslankard.googlepages.com/fluke.jpg

Is this a problem with my understanding of the thinning operation or is
it a problem with the THIN function? Any assistance is greatly
appreciated!

Regards,
Tom S.

0
6/29/2006 10:15:04 PM
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Ja, you are right. The idl implementation THIN seems to result from times  
where connectivity was an unfamiliar term. The routine is comparingly  
quick but not connectivity preserving. Maybe a closing (MORPH_CLOSE) might  
help in some cases.

Unluckily the implementation of EROSION and DILATION is likewise not just  
satisfying. I had a long fruitless discussion about that with RSI. At  
least they add some more documentation concerning the unusual border  
behaviour. Possibly critical remarks might help to convince VTT that there  
is some necessity to train somebody in mathematical morphology. In terms  
of math. morph and connectivity my reference is a very old program from  
Ecole de Mines, Fontainebleau, France, microMORPH, unluckily not freeware,  
where connectivity and border behaviour are implemented consistently.

Regards
Karsten

Am Fri, 30 Jun 2006 00:15:04 +0200 schrieb Tom S. <twslankard@gmail.com>:

> I had a question about the THIN function in IDL. I was under the
> impression that this operation was supposed to preserve connectivity.
> Am I mistaken? The IDL implementation does not seem to do so.
>
> The image linked below is output from a program I wrote. It simply
> takes the image on the left and applies the THIN function, yielding the
> image on the right. (Note the gap that forms toward the bottom.)
>
> http://twslankard.googlepages.com/fluke.jpg
>
> Is this a problem with my understanding of the thinning operation or is
> it a problem with the THIN function? Any assistance is greatly
> appreciated!
>
> Regards,
> Tom S.
>



-- 
Erstellt mit Operas revolution´┐Żrem E-Mail-Modul: http://www.opera.com/m2/
0
6/30/2006 6:45:34 AM
Yeah, I 've also noticed connectivity loss with THIN. I used Laplacian
filter  prior to thinning to insure the THIN doesn't remove thinner
parts ...

Regards,
Ulan

Karsten Rodenacker wrote:
> Ja, you are right. The idl implementation THIN seems to result from times
> where connectivity was an unfamiliar term. The routine is comparingly
> quick but not connectivity preserving. Maybe a closing (MORPH_CLOSE) might
> help in some cases.
>
> Unluckily the implementation of EROSION and DILATION is likewise not just
> satisfying. I had a long fruitless discussion about that with RSI. At
> least they add some more documentation concerning the unusual border
> behaviour. Possibly critical remarks might help to convince VTT that there
> is some necessity to train somebody in mathematical morphology. In terms
> of math. morph and connectivity my reference is a very old program from
> Ecole de Mines, Fontainebleau, France, microMORPH, unluckily not freeware,
> where connectivity and border behaviour are implemented consistently.
>
> Regards
> Karsten
>
> Am Fri, 30 Jun 2006 00:15:04 +0200 schrieb Tom S. <twslankard@gmail.com>:
>
> > I had a question about the THIN function in IDL. I was under the
> > impression that this operation was supposed to preserve connectivity.
> > Am I mistaken? The IDL implementation does not seem to do so.
> >
> > The image linked below is output from a program I wrote. It simply
> > takes the image on the left and applies the THIN function, yielding the
> > image on the right. (Note the gap that forms toward the bottom.)
> >
> > http://twslankard.googlepages.com/fluke.jpg
> >
> > Is this a problem with my understanding of the thinning operation or is
> > it a problem with the THIN function? Any assistance is greatly
> > appreciated!
> >
> > Regards,
> > Tom S.
> >
>
>
>
> --
> Erstellt mit Operas revolution=E4rem E-Mail-Modul: http://www.opera.com/m=
2/

0
7/5/2006 2:21:35 PM
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