| Re: thinning operation [message #25788] |
Tue, 17 July 2001 10:42 |
Thomas S. Spisz
Messages: 10
Registered: June 2000
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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:
> 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
>>
>> :-)
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| Re: thinning operation [message #25789 is a reply to message #25788] |
Tue, 17 July 2001 10:38  |
Thomas S. Spisz
Messages: 10
Registered: June 2000
|
Junior Member |
|
|
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:
> 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
>>
>> :-)
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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 |
|
|
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
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 <i>Zhang and Suen</i>. 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:
<br> <i>Medical & Biological Engineering & Computing</i>,
November, 1998.
<br> authors: Spisz, T.S.; Fang, Y.; Reeves, R.H.;
Seymour, C.K.; Bankman, I.N.; Hoh, J.H.;
<p>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.
<p>Hope this helps.
<p> --tom spisz
<br>
<p> ------------------------------------------------------------ ---------------------------------------------
<br>Julia wrote:
<blockquote TYPE=CITE>What I mean is that if it is a curve line with variable
width, how can
<br>I get the not-shorten skeleton. Do you mean it's impossible?
<p>Julia
<p>Craig Markwardt <craigmnet@cow.physics.wisc.edu> wrote in message
news:<on66cw7420.fsf@cow.physics.wisc.edu>...
<br>> julia65201@usa.net (Julia) writes:
<br>>
<br>> > Hi, there,
<br>> >
<br>> > In IDL, the THIN function returns the "skeleton" of a bi-level
image.
<br>> > But if it is a line, the reslut is shorter than the original one.
How
<br>> > can I prevent that?
<br>>
<br>> Make sure your lines don't have ends?
<br>>
<br>> Craig
<br>>
<br>> :-)</blockquote>
</html>
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| Re: thinning operation [message #25791 is a reply to message #25790] |
Tue, 17 July 2001 10:33 |
Thomas S. Spisz
Messages: 10
Registered: June 2000
|
Junior Member |
|
|
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
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 <i>Zhang and Suen</i>. 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:
<br> <i>Medical & Biological Engineering & Computing</i>,
November, 1998.
<br> authors: Spisz, T.S.; Fang, Y.; Reeves, R.H.;
Seymour, C.K.; Bankman, I.N.; Hoh, J.H.;
<p>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.
<p>Hope this helps.
<p> --tom spisz
<br>
<br>
<p>Julia wrote:
<blockquote TYPE=CITE>What I mean is that if it is a curve line with variable
width, how can
<br>I get the not-shorten skeleton. Do you mean it's impossible?
<p>Julia
<p>Craig Markwardt <craigmnet@cow.physics.wisc.edu> wrote in message
news:<on66cw7420.fsf@cow.physics.wisc.edu>...
<br>> julia65201@usa.net (Julia) writes:
<br>>
<br>> > Hi, there,
<br>> >
<br>> > In IDL, the THIN function returns the "skeleton" of a bi-level
image.
<br>> > But if it is a line, the reslut is shorter than the original one.
How
<br>> > can I prevent that?
<br>>
<br>> Make sure your lines don't have ends?
<br>>
<br>> Craig
<br>>
<br>> :-)</blockquote>
</html>
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| Re: thinning operation [message #25792 is a reply to message #25790] |
Tue, 17 July 2001 10:37 |
Thomas S. Spisz
Messages: 10
Registered: June 2000
|
Junior Member |
|
|
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
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 <i>Zhang and Suen</i>. 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:
<br> <i>Medical & Biological Engineering & Computing</i>,
November, 1998.
<br> authors: Spisz, T.S.; Fang, Y.; Reeves, R.H.;
Seymour, C.K.; Bankman, I.N.; Hoh, J.H.;
<p>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.
<p>Hope this helps.
<p> --tom spisz
<br>
<br>
<p>Julia wrote:
<blockquote TYPE=CITE>What I mean is that if it is a curve line with variable
width, how can
<br>I get the not-shorten skeleton. Do you mean it's impossible?
<p>Julia
<p>Craig Markwardt <craigmnet@cow.physics.wisc.edu> wrote in message
news:<on66cw7420.fsf@cow.physics.wisc.edu>...
<br>> julia65201@usa.net (Julia) writes:
<br>>
<br>> > Hi, there,
<br>> >
<br>> > In IDL, the THIN function returns the "skeleton" of a bi-level
image.
<br>> > But if it is a line, the reslut is shorter than the original one.
How
<br>> > can I prevent that?
<br>>
<br>> Make sure your lines don't have ends?
<br>>
<br>> Craig
<br>>
<br>> :-)</blockquote>
</html>
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| Re: thinning operation [message #25793 is a reply to message #25790] |
Tue, 17 July 2001 10:30 |
Thomas S. Spisz
Messages: 10
Registered: June 2000
|
Junior Member |
|
|
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:
> 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
>>
>> :-)
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| Re: thinning operation [message #25816 is a reply to message #25815] |
Fri, 13 July 2001 17:22 |
Craig Markwardt
Messages: 1869
Registered: November 1996
|
Senior Member |
|
|
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
:-)
--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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