<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Gen-Nan, <div>Hessian3DToVesselnessMeasureImageFilter does not <div>`detect' the vessels but it `enhances' them. </div><div><br></div><div>Have a look at the original paper by Frangi et al </div><div><a href="http://www.tecn.upf.es/~afrangi/articles/miccai1998.pdf">http://www.tecn.upf.es/~afrangi/articles/miccai1998.pdf</a><br><div apple-content-edited="true"> </div><br></div><div>Cagatay Bilgin</div><div><br><div><div>On Feb 21, 2009, at 7:40 PM, Gen-Nan Chen wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> Hi! All,<br><br>I tried to use Hessian3DToVesselnessMeasureImageFilter to segment vessel tree in the lung. I have a few questions here<br><br>1. The output Image of Hessian3DToVesselnessMeasureImageFilter is not a binary image as I thought. Can anyone tell me what those voxel value mean? Do I need to <br> \<br>2. HessianRecursiveGaussianImageFilter's sigma. Anyone know what does this sigma value mean and for? Looks like I can get a biggger vessel by using a bigger sigma?<br><br>3. For thin tube like those vessels in the lung, what's the recommendation value for alph1 and alph2?<br clear="all"> <br>-- <br>Gen-Nan Chen, <br>email: <a href="mailto:gnchen@gmail.com">gnchen@gmail.com</a><br> _____________________________________<br>Powered by <a href="http://www.kitware.com">www.kitware.com</a><br><br>Visit other Kitware open-source projects at<br><a href="http://www.kitware.com/opensource/opensource.html">http://www.kitware.com/opensource/opensource.html</a><br><br>Please keep messages on-topic and check the ITK FAQ at: http://www.itk.org/Wiki/ITK_FAQ<br><br>Follow this link to subscribe/unsubscribe:<br>http://www.itk.org/mailman/listinfo/insight-users<br></blockquote></div><br></div></div></body></html>