[vtkusers] strange output, any advice please

[Bill Lorensen]

The example's output is an isosurface made of of triangles. Also, as
the description says,
"This example creates polydata models from a 3D volume that contains
discrete labels. These volume are normally the output of a
segmentation algorithm." It looks as though infoseekerr is generating
an isosurface from grayscale data.

Delaunay3D creates a volume of tetrahedras from a pointset. As you
mentioned I believe it is a convex hull.. They serve different
purposes. It is not clear what the problem is that infoseekerr is
trying to solve. Until infoseekeer can explaint the problem, I don't
see how we can be of any help.


On Thu, Dec 17, 2009 at 8:49 AM, David Doria <daviddoria+vtk at gmail.com> wrote:
> On Thu, Dec 17, 2009 at 8:08 AM, Ali Habib <ali.mahmoud.habib at gmail.com> wrote:
>> Dear Bill,
>> I used VtkDelunary3D instead of 2D, and I used before reconstruction series
>> of fillters to decrease the dataset ,attached is the output
>>
>> The code I used is :
>>
>> vtkDICOMImageReader v16 =  vtkDICOMImageReader::New();
>>
>>             v16->SetDirectoryName(@"D:\work\Master
>> Degree\DataSet\case2\DICOM\PA1\ST1\SE2");
>>
>>             v16->SetDataOrigin(2, 2, 1);
>>
>>             v16->Update();
>>
>>             /////////////////////Pre processing
>>
>>             // STEP 1:
>>
>>             vtkImageShrink3D VIS =  vtkImageShrink3D::New();
>>
>>             VIS->SetInputConnection(v16->GetOutputPort());
>>
>>             VIS->SetShrinkFactors(2, 2, 1);
>>
>>             VIS->Update();
>>
>>             // STEP 2:
>>
>>             vtkImageThreshold VIT =  vtkImageThreshold::New();
>>
>>             VIT->SetInputConnection(VIS->GetOutputPort());
>>
>>             VIT->ThresholdByLower(200);
>>
>>             VIT->ThresholdByUpper(2000);
>>
>>             VIT->Update();
>>
>>             //step3
>>
>>             vtkImageGaussianSmooth VIG = vtkImageGaussianSmooth::New();
>>
>>             VIG->SetInputConnection(VIS->GetOutputPort());
>>
>>             VIG->SetStandardDeviation(1.4, 1.4, 1.4);
>>
>>             VIG->Update();
>>
>>
>>
>>             //////////////// Create the 3d volume /////////////////
>>
>>
>>
>>             vtkMarchingCubes skinExtractor =  vtkMarchingCubes::New();
>>
>>             skinExtractor->GetOutput()->ReleaseDataFlagOff();
>>
>>             skinExtractor->SetInputConnection(VIG->GetOutputPort());
>>
>>             skinExtractor->SetValue(0, 500);
>>
>>             skinExtractor->ComputeGradientsOn();
>>
>>             skinExtractor->Update();
>>
>>
>>
>>             vtkTriangleFilter VTF =  vtkTriangleFilter::New();
>>
>>             VTF->SetInputConnection(skinExtractor->GetOutputPort());
>>
>>             VTF->GetOutput()->ReleaseDataFlagOff();
>>
>>             VTF->Update();
>>
>>
>>
>>             vtkDelaunay3D stripper =  vtkDelaunay3D::New();
>>
>>             stripper->SetInputConnection(VTF->GetOutputPort());
>>
>>             stripper->GetOutput()->ReleaseDataFlagOff();
>>
>>             stripper->Update();
>>
>>
>>
>>             // Create Mapper
>>
>>            vtkDataSetMapper skinMapper =  vtkDataSetMapper::New();
>>
>>            skinMapper->SetInputConnection(stripper->GetOutputPort());
>>
>>
>>
>>
>>
>>
>
> That is the expected output of Delaunay3D. I never understood what it
> would be used for myself. It is very "convex-hull-ish".
>
> I'm not exactly sure what the output of this example is, and I'm also
> not very familiar with DICOM, but maybe you can look at:
> http://www.vtk.org/Wiki/VTK/Examples/Medical/Cxx/GenerateModelsFromLabels
>
> (Bill - we should try to add images to a lot of these as we have time).
>
> Thanks,
>
> David
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