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Re: thinning operation [message #25790 is a reply to message #25789]

Tue, 17 July 2001 10:32

Thomas S. Spisz
Messages: 10
Registered: June 2000

Junior Member

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I'm not sure whether it's impossible, but I do know that most thinning
algorithms will shorten the line (especially with variable width). 
I've used the 'THIN' function and also implemented in IDL some algorithms
published in literature such as ones by Zhang and Suen.  What
I've done about the line shortening effect is to return the end pixels
of each line.  This is done by extending points from the thinned line
in the direction of the last two pixels and comparing it to the original
thick line.  If there was a pixel in the thick line, then extend the
thin line one pixel and keep going.  I described this in the journal:
     Medical & Biological Engineering & Computing,
November, 1998.
     authors:  Spisz, T.S.; Fang, Y.; Reeves, R.H.;
Seymour, C.K.; Bankman, I.N.; Hoh, J.H.; 
By your questions and your previous question about 'LABEL_REGION', I'm
guessing that you are trying to find the length of certain things in an
image.  I've published a couple papers on this in addition to the
one I listed above.
Hope this helps.
  --tom spisz
  
 ------------------------------------------------------------ ---------------------------------------------
 Julia wrote:
<blockquote TYPE=CITE>What I mean is that if it is a curve line with variable
width, how can
 I get the not-shorten skeleton. Do you mean it's impossible?
Julia
Craig Markwardt <craigmnet@cow.physics.wisc.edu> wrote in message
news:<on66cw7420.fsf@cow.physics.wisc.edu>...
 > julia65201@usa.net (Julia) writes:
 >
 > > Hi, there,
 > >
 > > In IDL, the THIN function returns the "skeleton" of a bi-level
image.
 > > But if it is a line, the reslut is shorter than the original one.
How
 > > can I prevent that?
 >
 > Make sure your lines don't have ends?
 >
 > Craig
 >
 > :-)</blockquote>
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[Message index]

		Re: thinning operation By: Thomas S. Spisz on Tue, 17 July 2001 10:42
		Re: thinning operation By: Thomas S. Spisz on Tue, 17 July 2001 10:38
		Re: thinning operation By: Thomas S. Spisz on Tue, 17 July 2001 10:32
		Re: thinning operation By: Thomas S. Spisz on Tue, 17 July 2001 10:33
		Re: thinning operation By: Thomas S. Spisz on Tue, 17 July 2001 10:37
		Re: thinning operation By: Thomas S. Spisz on Tue, 17 July 2001 10:30
		Re: thinning operation By: julia65201 on Fri, 13 July 2001 22:11
		Re: thinning operation By: Craig Markwardt on Fri, 13 July 2001 17:22

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