<div dir="ltr">Great!</div><div class="gmail_extra"><br><div class="gmail_quote">On Sun, Dec 6, 2015 at 10:44 AM, Imre Goretzki <span dir="ltr"><<a href="mailto:goretzki.imre@gmail.com" target="_blank">goretzki.imre@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
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    Thank you Cory,<br>
    <br>
    I implemented the vtkThreshold today, now it is working fine.<span class="HOEnZb"><font color="#888888"><br>
    <br>
    Imre</font></span><div><div class="h5"><br>
    <br>
    <div>Am 06.12.2015 um 16:22 schrieb Cory
      Quammen:<br>
    </div>
    <blockquote type="cite">
      <div dir="ltr">
        <div class="gmail_extra">
          <div class="gmail_quote">On Sat, Dec 5, 2015 at 1:15 PM, Imre
            Goretzki <span dir="ltr"><<a href="mailto:goretzki.imre@gmail.com" target="_blank">goretzki.imre@gmail.com</a>></span>
            wrote:<br>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Hey
              guys,<br>
              <br>
              I have a question about the "GenerateValues" method of
              MarchingCubes. My image has several points that have
              intensity values that lie between 928 and 1600.<br>
              <br>
              My understand of<br>
              <br>
              int idxContour = 1;<br>
              double from = 920;<br>
              double to = 930;<br>
              <br>
              ImageToVTKImageFilter con = ...<br>
              <br>
              marchingCube->setInputData(con->GetOutput());<br>
              marchingCube->GenerateValues(idxContour, from, to);<br>
              marchingCube->Update();<br>
              <br>
              is that the algorithm will take all points that have an
              intensity value that lies between 920 and 930. These
              points are combined to one contour. Via MATLAB and ITK's
              histogram I can validate the amout of points that have a
              specific intensity value. </blockquote>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"> </blockquote>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">If
              I plot the points that were generated by marching cubes, I
              do not get all of them (I cannot see all of them), e.g.<br>
              the histogram says that there are about 200000 points that
              have an intensity value 928. If I use 928 as the lower
              bound for the GenerateValues method, there are just some
              of them plotted - approximately.<br>
              <br>
              Is my understanding of GenerateValues correct?<br>
            </blockquote>
            <div> </div>
            <div>
              <div>Not exactly. vtkMarchingCubes will extract individual
                isocontours - surfaces that represent the locations in a
                dataset with a particular value. vtkMarchingCubes and
                other isocontour filters in VTK can generate surfaces
                from more than one isovalue. GenerateValues() is a
                convenience function to specify a range of isovalues.</div>
              <div><br>
              </div>
              <div>A vtkThreshold filter will extract all points in the
                dataset in a value range and may be what you want.</div>
            </div>
            <div> </div>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Next
              question: (more than 1 contour)<br>
              <br>
              If I want to generate more than 1 contour. How do I
              initialize the marchingCube and, more interesting, how do
              I get the output of a specific contour. I'm thinking about
              the following:<br>
              <br>
              <br>
              marchingCube->SetNumberOfContours(2);<br>
              marchingCube->GenerateValues(1, from_1, to_1);<br>
              marchingCube->GenerateValues(2, from_2, to_2);<br>
              <br>
              vtkSmartPointer<vtkOutlineFilter> outline =
              vtkSmartPointer<vtkOutlineFilter>::New();<br>
outline->SetInputConnection(marchingCube->GetOutput(1));<br>
              <br>
              vtkSmartPointer<vtkPolyDataMapper> outlineMapper =
              vtkSmartPointer<vtkPolyDataMapper>::New();<br>
outlineMapper->SetInputConnection(outline->GetOutputPort());<br>
              <br>
              vtkSmartPointer<vtkPolyDataMapper> data1 =
              vtkSmartPointer<vtkPolyDataMapper>::New();<br>
data1->SetInputConnection(marchingCube->GetOutput(1));<br>
              <br>
              vtkSmartPointer<vtkPolyDataMapper> data2 =
              vtkSmartPointer<vtkPolyDataMapper>::New();<br>
data2->SetInputConnection(marchingCube->GetOutput(2));<br>
              <br>
              I know that the above lines are not working like this, but
              I actually do not know how to do that. Right now I have 2
              marchingCube instances that do the work for data1/data2
              but that should not do the trick.<br>
            </blockquote>
            <div><br>
            </div>
            <div>You can't set up two different isocontour surfaces and
              get two different outputs this way. Using two separate
              vtkMarchingCubes instances is the right way to go.</div>
            <div><br>
            </div>
            <div>HTH,</div>
            <div>Cory</div>
            <div> </div>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>
              I hope you can help me<br>
              <br>
              Greetings<br>
              Imre<br>
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            </blockquote>
          </div>
          <br>
          <br clear="all">
          <div><br>
          </div>
          -- <br>
          <div>Cory Quammen<br>
            R&D Engineer<br>
            Kitware, Inc.</div>
        </div>
      </div>
    </blockquote>
    <br>
  </div></div></div>

</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">Cory Quammen<br>R&D Engineer<br>Kitware, Inc.</div>
</div>