<br><br>Hi Baoyun,<br><br>You may not need to reinitialize the level set at every iteration.<br><br>In principle, the zero set doesn't move more than one pixel at<br>every iteration, so I would think that you should only need to<br>
reinitialize after a number of iterations that is equal to the half<br>width of the narrow band (measured in pixels).<br><br><br>Whether the approach is practical in term of computation time is<br>something that can only be defined by knowing the requirements<br>
of your segmentation and the capabilities of the computation <br>platform that you have at hand.<br><br>I would suggest that you instrument the code with TimeProbes<br>and profile how much time is spent on every subtask.<br>
<br>Please, make sure that you are compiling for Release before<br>you start profiling the computation time.<br><br><br> Regards,<br><br><br> Luis<br><br><br><br>----------------------------------------------------------------------------------------------<br>
<div class="gmail_quote">On Mon, Mar 8, 2010 at 5:49 PM, Baoyun Li <span dir="ltr"><<a href="mailto:baoyun_li123@yahoo.com">baoyun_li123@yahoo.com</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;">
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<div>Hi, Luis:</div>
<div> </div>
<div>Thanks so much.</div>
<div> </div>
<div>I program is based release model. Five mimutes is for not using narrarow band. How long time usually need for this filter with narrow band 12 for the 512*512*100 ct images? My plan is to use ReinitializeLevelSetImageFilter at each iteration. Do you think it is practial in terms of computation time.</div>
<div> </div>
<div>I now make the ReinitializeLevelSetImageFilter works using binary image. The image has 0 and 255 intensity value. I set the levesetvale to be 128, it seems works.</div>
<div> </div>
<div>My best regars</div>
<div> </div>
<div>Baoyun<div class="im"><br>--- On <b>Sat, 3/6/10, Luis Ibanez <i><<a href="mailto:luis.ibanez@kitware.com" target="_blank">luis.ibanez@kitware.com</a>></i></b> wrote:<br></div></div>
<blockquote style="border-left: 2px solid rgb(16, 16, 255); padding-left: 5px; margin-left: 5px;"><div class="im"><br>From: Luis Ibanez <<a href="mailto:luis.ibanez@kitware.com" target="_blank">luis.ibanez@kitware.com</a>><br>
Subject: Re: [Insight-users] how to use ReinitializeLevelSetImageFilter<br>To: "Baoyun Li" <<a href="mailto:baoyun_li123@yahoo.com" target="_blank">baoyun_li123@yahoo.com</a>><br>Cc: <a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a><br>
</div>Date: Saturday, March 6, 2010, 10:28 PM<div><div></div><div class="h5"><br><br>
<div><br>Hi Baoyun,<br><br>The input to the ReinitializeLevelSetImageFilter <br>is not expected to be a binary image.<br><br>The input image is supposed to be a level set image.<br><br>The purpose of the filter is to correct the drift that will<br>
happens in a level set image due to the inaccuracies<br>of computing its progress based only on a narrow band<br>of pixels.<br><br>Five minutes is an abnormally long time for this filter.<br><br>Are you compiling your code for "Debug" mode ?<br>
<br><br> Luis<br><br><br>------------------------------------------------------------------------------------------<br>
<div class="gmail_quote">On Tue, Mar 2, 2010 at 11:53 AM, Baoyun Li <span dir="ltr"><<a href="http://us.mc1110.mail.yahoo.com/mc/compose?to=baoyun_li123@yahoo.com" rel="nofollow" target="_blank">baoyun_li123@yahoo.com</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;">
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<div>Dear Luis:</div>
<div> </div>
<div>I tried to add SetLevelSetValue(0) and SetLevelSetValue(128). And set narrowbandoff.</div>
<div>However, I am getting same weird result.</div>
<div> </div>
<div>So can you tell me whether the input of ReinitializeLevelSetImageFilter is binary image.</div>
<div> </div>
<div>And the filter needs five mintues to run, is it normal for a 512x512x60 image.</div>
<div> </div>
<div>Thanks and my best regards</div>
<div> </div>
<div>Baoyun<br><br><br>--- On <b>Mon, 3/1/10, Luis Ibanez <i><<a href="http://us.mc1110.mail.yahoo.com/mc/compose?to=luis.ibanez@kitware.com" rel="nofollow" target="_blank">luis.ibanez@kitware.com</a>></i></b> wrote:<br>
</div>
<blockquote style="border-left: 2px solid rgb(16, 16, 255); padding-left: 5px; margin-left: 5px;"><br>From: Luis Ibanez <<a href="http://us.mc1110.mail.yahoo.com/mc/compose?to=luis.ibanez@kitware.com" rel="nofollow" target="_blank">luis.ibanez@kitware.com</a>><br>
Subject: Re: [Insight-users] how to use ReinitializeLevelSetImageFilter<br>To: "Baoyun Li" <<a href="http://us.mc1110.mail.yahoo.com/mc/compose?to=baoyun_li123@yahoo.com" rel="nofollow" target="_blank">baoyun_li123@yahoo.com</a>>
<div><br>Cc: <a href="http://us.mc1110.mail.yahoo.com/mc/compose?to=insight-users@itk.org" rel="nofollow" target="_blank">insight-users@itk.org</a><br></div>Date: Monday, March 1, 2010, 11:50 PM
<div>
<div></div>
<div><br><br>
<div><br>Hi Baoyun,<br><br><br>It looks like you missed to call the method:<br><br> SetLevelSetValue()<br><br>before you called Update() in the filter.<br><br>For guidance, please look at the file:<br><br>
Insight/Testing/Code/Algorithms/<br> itkReinitializeLevelSetImageFilterTest.cxx<br><br><br> Regards,<br><br><br> Luis<br><br><br>------------------------------------------------------<br>
<div class="gmail_quote">On Mon, Mar 1, 2010 at 2:56 PM, Baoyun Li <span dir="ltr"><<a href="http://us.mc1110.mail.yahoo.com/mc/compose?to=baoyun_li123@yahoo.com" rel="nofollow" target="_blank">baoyun_li123@yahoo.com</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;">
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<div>Dear All: </div>
<div> </div>
<div>I tried to use ReinitializeLevelSetImageFilter. The output looks weird to me. </div>
<div> </div>
<div>The input to the filter is binary image binary image with float type (255 as forground, 0 as background).</div>
<div> </div>
<div>I tried narroow band on and off. However, the output of this filter gives very high value (10^38) for voxles inside the binary mask. Almost all the outside mask voxels has value zero.</div>
<div> </div>
<div>Below is my code, can somebody tell where I made mistake.</div>
<div> </div>
<div>Baoyun</div>
<div> </div>
<div> </div>
<div>**************************code************************<br> typedef typename itk::ReinitializeLevelSetImageFilter< FeatureImageType > DistanceFilterType; <br> typename DistanceFilterType::Pointer DistanceFilter = DistanceFilterType::New(); <br>
DistanceFilter->SetInput( thresholder->GetOutput() ); <br> // DistanceFilter->NarrowBandingOn(); <br> // DistanceFilter->SetNarrowBandwidth( 10 ); <br> try<br> {<br> DistanceFilter->Update(); </div>
<div> }<br> catch( itk::ExceptionObject & excep )<br> {<br> std::cerr << "Exception caught !" << std::endl;<br> std::cerr << excep << std::endl;<br> }</div>
<div> </div>
<div> m_levelset2=DistanceFilter->GetOutput();</div>
<div> </div>
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