<div class="moz-text-flowed" style="font-family: -moz-fixed; font-size: 12px;" lang="x-western">Dear all,
<br>
<br>I am a little bit confused about the level set implementation in ITK.
<br>my questions are according to
<br>
<br><a class="moz-txt-link-freetext" href="http://www.itk.org/Doxygen32/html/itkLevelSetFunction_8h.html">http://www.itk.org/Doxygen32/html/itkLevelSetFunction_8h.html</a> and
<br><a class="moz-txt-link-freetext" href="http://www.itk.org/Doxygen32/html/itkSegmentationLevelSetFunction_8h.html">http://www.itk.org/Doxygen32/html/itkSegmentationLevelSetFunction_8h.html</a>
<br>
<br>There exist m_FeatureImage, m_SpeedImage, m_AdvectionImage,
PropagationSpeed, CurvatureSpeed. The levelset function to be solved is
given as :
<br>
<br><a class="moz-txt-link-freetext" href="http://www.itk.org/Doxygen32/html/form_149.png">http://www.itk.org/Doxygen32/html/form_149.png</a>
<br>
<br>I think
<br>m_AdvectionImage = A(x);
<br>PropagationSpeed = P(x);
<br>CurvatureSpeed = Z(x);
<br>
<br>1- According to my understand the m_SpeedImage is expected to be
calculated from the m_FeatureImage in a desired fashion. that's why it
is not implemented. However I can not find the connection of this
m_SpeedImage with the A, P, Z terms?
<br>2- How Z is calculated, I could not find anything about it also?
<br>3- According to Osher's Level Set Methods book the right hand side of
the equation
<br><a class="moz-txt-link-freetext" href="http://www.itk.org/Doxygen32/html/form_149.png">http://www.itk.org/Doxygen32/html/form_149.png</a>
<br>should be calculated by using center differences. Is it implemented like
that?
<br>4- Are the magnitude of the gradients of Phi same for the right and left
side of that equation? (since the left side should use the upwind
methods where the right side should use center differences)
<br>
<br>If anyone can answer my implementation and theory based questions I will
be so glad. And also any reference to headers or sources are welcome.
<br>
<br>Thank you in advance
<br>
<br>Burak
<br>
<br>
<br></div>
<table class="moz-vcard-table"> <tbody><tr> <td valign="top"> <br></td><td> <table id="moz-vcard-properties-table"> <tbody><tr> <td class="moz-vcard-title-property"> Burak Ozkalayci <<a href="mailto:burak.ozkalayci@UGent.be">
burak.ozkalayci@UGent.be</a>></td> </tr> <tr> <td class="moz-vcard-property">PhD Student</td> </tr> <tr> <td class="moz-vcard-property">Electronic and Information Systems (ELIS-MEDISIP)</td> </tr> <tr> <td class="moz-vcard-property">
Ghent University Hospital - IBITECH</td> </tr> </tbody></table> </td> </tr> </tbody></table>