Using the hessian you can look for tubular structures easily. ITK has some functions related oriented do enhance vessels (that are similar to your fibers).<div><br></div><div>There are also minor modifications of the hessian filter that sould be able to respond well to plate-like structures as far as I remember...</div>
<div><br></div><div>Look for Alejandro Frangi Vesselness measure. His paper explains the combination of eigenvalues of the Hessian that respond well to tubes and to plates.</div><div><br></div><div><br><br><div class="gmail_quote">
On Tue, Jul 20, 2010 at 5:34 PM, <span dir="ltr"><<a href="mailto:lynx.abraxas@freenet.de">lynx.abraxas@freenet.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hello!<br>
<br>
<br>
Is it possible to destinguish sheets from fibers by a filter (chain)?<br>
The fibers are ideally abritarily bend cylinders of diameter d and the sheets<br>
are ideally abritrarily bend planes with a thickness d as well. The fibers and<br>
sheets are randomly distributed in 3D space.<br>
<br>
I was thinking if this can be done by a 3D FFT, finding the local maxima in<br>
the FFT-amplitude image, masking these with a local or global threshold and<br>
then doing a inverse FFT of only what is within the mask.<br>
Would this work? Would the sheets yield a stronger signal in the FFT than the<br>
fibers?<br>
Is there any other way to do this?<br>
Is there perhaps some kind of skeletonization filter that would make it<br>
possible to destinguish parts from the skeleton that belong to the sheets and<br>
parts that belong to fibers?<br>
<br>
What approach would be best if d is not exact but varies?<br>
<br>
<br>
Thanks for any help or hints.<br>
Lynx<br>
<br>
<br>
_____________________________________<br>
Powered by <a href="http://www.kitware.com" target="_blank">www.kitware.com</a><br>
<br>
Visit other Kitware open-source projects at<br>
<a href="http://www.kitware.com/opensource/opensource.html" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>
<br>
Kitware offers ITK Training Courses, for more information visit:<br>
<a href="http://www.kitware.com/products/protraining.html" target="_blank">http://www.kitware.com/products/protraining.html</a><br>
<br>
Please keep messages on-topic and check the ITK FAQ at:<br>
<a href="http://www.itk.org/Wiki/ITK_FAQ" target="_blank">http://www.itk.org/Wiki/ITK_FAQ</a><br>
<br>
Follow this link to subscribe/unsubscribe:<br>
<a href="http://www.itk.org/mailman/listinfo/insight-users" target="_blank">http://www.itk.org/mailman/listinfo/insight-users</a><br>
</blockquote></div><br><br clear="all"><br>-- <br>Sergio Vera<br><br> Alma IT Systems<br> C/ Vilana, 4B, 4º 1ª<br> 08022 Barcelona<br> T. (+34) 932 380 592<br> <a href="http://www.alma3d.com">www.alma3d.com</a><br>
</div>