| Re: connected component labeling problem in a graylevel image without background [message #32470] |
Tue, 15 October 2002 00:52  |
Karsten Rodenacker
Messages: 98
Registered: July 1997
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Member |
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Julia schrieb:
>
> I am not quite familiar with watershed algorithm. But in my understanding,
> "considering the gray scale image
> as a surface, each local minimum can be thought of as the point to which
> water falling on the surrounding
> region drains. The boundaries of the watersheds lie on the tops of the
> ridges. This operator labels each
> watershed region with a unique index, and sets the boundaries to zero.
> Typically, morphological gradients,
> or images containing extracted edges are used for input to the watershed
> operator."
>
> If I use watershed operator on the image, since it labels some pixels as
> boundaries, it will eliminate some regions
> with one-pixel width and label them as boundaries. That is not what I want.
> Can watershed algorithm really solve this?
1 px width boundaries guarantee connected regions which can lateron
relabelled e.g. by label_region. However the algorithm implemented by
rsi generates boundaries, there are other watershed algorithms which
generate touching regions without boundaries. I have a pure idl
implementation under
http://www.gsf.de/ILIAD/Rodenacker/IDL/MM.html#Watershed designed in
times before morph_... and n-dim label_region existed which performs in
that way (doc. in German). (Still I wait for idl watershed on 3d data
which comprises a very simple extension of the original watershed
algorithm).
>
> Regards,
>
--
Karsten Rodenacker ()
------------------------------------------------------------ -------------:-)
GSF - Forschungszentrum Institute of Biomathematics and Biometry
D-85758 Oberschleissheim Postfach 11 29
Tel: +49 89 31873401 | FAX: ...3369 | rodena@gsf.de |
Karsten@Rodenacker.de
http://www.gsf.de/ibb/homepages/rodenacker
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