Hi,<br><br>Coincidentally, I have an adaptive threshold filter that is similar to the one available in MATLAB Central. It makes use of a median filter to estimate the local bias and computes an Otsu threshold locally at a point for a given neighborhood. I was planning to submit this to ITK shortly.<br>
<br>However, it is not based on the connected component method described below. If you are interested, I can send it to you.<br><br>Kishore<br><br><br><br><div class="gmail_quote">On Thu, Sep 17, 2009 at 5:09 AM, Lassi Paavolainen <span dir="ltr"><<a href="mailto:lassi.paavolainen@jyu.fi">lassi.paavolainen@jyu.fi</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi Edward,<br>
<br>
I haven't seen any adaptive threshold method in ITK.<div class="im"><br>
<br>
On Thu, 17 Sep 2009, Somer, Edward wrote:<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I'd write a class that inherited ConnectedThresholdImageFilter and add an observer to update the lower threshold at each iteration as a set percentage of the region mean. The filter would be initialised with a seed point and iterate until the region grew no further.<br>
</blockquote>
<br></div>
This sounds correct if you are planning to do adaptive region growing segmentation. We have done adaptive threshold in BioImageXD project just by using mean or median filter and then comparing this result image to the original one. I guess this sort of adaptive thresholding is not what you are looking for, but you specifically want to do it in region growing way?<br>
<br>
Anyway the code is available at:<br>
<a href="http://bioimagexd.svn.sourceforge.net/viewvc/bioimagexd/bioimagexd/trunk/itkBXD/Algorithms/itkDynamicThreshold3DImageFilter.txx?revision=1473" target="_blank">http://bioimagexd.svn.sourceforge.net/viewvc/bioimagexd/bioimagexd/trunk/itkBXD/Algorithms/itkDynamicThreshold3DImageFilter.txx?revision=1473</a><br>
<a href="http://bioimagexd.svn.sourceforge.net/viewvc/bioimagexd/bioimagexd/trunk/itkBXD/Algorithms/itkDynamicThreshold3DImageFilter.h?revision=1473" target="_blank">http://bioimagexd.svn.sourceforge.net/viewvc/bioimagexd/bioimagexd/trunk/itkBXD/Algorithms/itkDynamicThreshold3DImageFilter.h?revision=1473</a><br>
<br>
for anyone who is interested.<br>
<br>
Lassi<br><font color="#888888">
<br>
-- <br>
Lassi Paavolainen, M.Sc.<br>
Software Engineer<br>
BioImageXD (<a href="http://www.bioimagexd.net" target="_blank">http://www.bioimagexd.net</a>)<br>
<a href="mailto:lassi.paavolainen@jyu.fi" target="_blank">lassi.paavolainen@jyu.fi</a></font><div><div></div><div class="h5"><br>
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