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<div style="direction:ltr; font-family:Tahoma; color:#000000; font-size:10pt">Dear ITK users,
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I'm playing with the Chan-Vese level sets example SingleLevelSetWhitaker; when I use the cells.png image, it seems to work fine: the contour is initialized completely outside of the cell shapes, and the front is inward moving, culminating in a fairly successful
segmentation. When I try to substitute some other image, and initializing the model completely outside the structure of interest again, for whatever reason, the contour seems push _outwards_ . The only thing that I've changed is the input image, and the size
given to the region class. <br>
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What would account for this type of behavior? To be frank, I don't understand where the speed term comes from (the so-called advection term in Malladi and Sethian...), so I don't know how to tweak this term in Chan-Vese .<br>
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Thanks for your kind support.<br>
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Cheers, <br>
<br>
Michel<br>
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<div><font face="Tahoma" size="2">Michel Audette, Ph.D. </font></div>
<div><font face="tahoma" size="2">Assistant Professor,</font></div>
<div><font face="tahoma" size="2">Department of Modeling, Simulation and Visualization Engineering,</font></div>
<div><font face="tahoma" size="2">Old Dominion University,</font></div>
<div><font face="Tahoma" size="2">Norfolk, VA.</font></div>
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<div id="divRpF682573" style="direction:ltr"><font color="#000000" face="Tahoma" size="2"><b>From:</b> Audette, Michel A.<br>
<b>Sent:</b> Friday, June 07, 2013 4:13 PM<br>
<b>To:</b> insight-users@itk.org<br>
<b>Subject:</b> 2 questions about Level Sets in ITK: triangulating isosurface and how to tune ShapeDetectionLevelSetSegmentation<br>
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<div style="direction:ltr; font-family:Tahoma; color:#000000; font-size:10pt">Dear ITK users,
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<div>I have two questions on Level Sets in ITK. </div>
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<div>Is there a Level Sets model that is triangulated, i.e.: produces a watertight polygonalization of the zero-level isosurface? Is there a way to produce this watertight triangulation? I know that VTK has Marching Cubes, but I have misgivings about this method
producing a watertight result. </div>
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<div>Second, I would like to use an example with phantom images that are narrow structures, similar to the Circle of Willis, but in 2D, and I would like to have a recommendation for working example code that I can use with this. I have tried ShapeDetectionLevelSetSegmentation,
but I find this example produces a constant speed term, as opposed to a speed term that halts the model on high-gradient areas of the image. </div>
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<div>Please advise. </div>
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<div>Thanks for your kind consideration.</div>
<div><br>
</div>
<div>Michel<br>
<div><br>
<div><font face="Tahoma" size="2">Michel Audette, Ph.D. </font></div>
<div><font face="tahoma" size="2">Assistant Professor,</font></div>
<div><font face="tahoma" size="2">Department of Modeling, Simulation and Visualization Engineering,</font></div>
<div><font face="tahoma" size="2">Old Dominion University,</font></div>
<div><font face="Tahoma" size="2">Norfolk, VA.</font></div>
<div><font face="tahoma" size="2"></font> </div>
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