[vtkusers] vtkPolyDataToImageStencil noise issue

[Raghuram.O.S.]

I have attached a slice of the generated mhd image.

On Mon, Mar 19, 2012 at 11:50 AM, Raghuram.O.S. <raghuramos1987 at gmail.com>wrote:

>
>
> On Mon, Mar 19, 2012 at 7:35 AM, Jothybasu Selvaraj <jothybasu at gmail.com>wrote:
>
>> What is your polydata made of?
>>
>> Is it from 2D contours?
>>
>
> My polydata has 3D triangles. Here is the DumpXML output for it.
> ------------------------
> out_p_w.vtk
>  contains a
> vtkPolyData that has 1310888 cells and 1772275 points.
> Cell type vtkTriangle occurs 1310888 times.
>  contains point data with 2 arrays.
> Array 0 is named scalars
> Array 1 is named Normals
>  contains cell data with 0 arrays.
>  contains field data with 0 arrays.
>
>
>
>>
>> You may post your code, that would make people to help you better.
>>
>
> Sorry, I should have done that.
>
> int main(int, char *[])
> {
>     vtkSmartPointer<vtkPolyDataReader> pdR =
>         vtkSmartPointer<vtkPolyDataReader>::New();
>   vtkSmartPointer<vtkSphereSource> sphereSource =
>     vtkSmartPointer<vtkSphereSource>::New();
>   vtkSmartPointer<vtkWarpScalar> warp=
>     vtkSmartPointer<vtkWarpScalar>::New();
>   sphereSource->SetRadius(20);
>   sphereSource->SetPhiResolution(30);
>   sphereSource->SetThetaResolution(30);
>   pdR->SetFileName("../../data/vtk/out_p_w.vtk");
>   //pdR->SetFileName("../../data/vtk/out_poly_append_one.vtk");
>   //pdR->SetFileName("../../vis/out_poly.vtk");
>   //vtkSmartPointer<vtkPolyData> pd = sphereSource->GetOutput();
>   pdR->Update();
>   vtkSmartPointer<vtkPolyData> pd = pdR->GetOutput();
>   //warp->SetInput(pd);
>   //warp->SetScaleFactor(10);
>   //warp->Update();
>   //vtkSmartPointer<vtkPolyData> pd =
>   //pd = warp->GetOutput();
>   //sphereSource->Update();
>
>   vtkSmartPointer<vtkImageData> whiteImage =
>     vtkSmartPointer<vtkImageData>::New();
>   double bounds[6];
>   pd->GetBounds(bounds);
>   double spacing[3]; // desired volume spacing
>   spacing[0] = 0.31;
>   spacing[1] = 0.31;
>   spacing[2] = 0.31;
>   whiteImage->SetSpacing(spacing);
>
>   // compute dimensions
>   int dim[3];
>   for (int i = 0; i < 3; i++)
>     {
>     dim[i] = static_cast<int>(ceil((bounds[i * 2 + 1] - bounds[i * 2]) /
> spacing[i]));
>     }
>   whiteImage->SetDimensions(dim);
>   whiteImage->SetExtent(0, dim[0] - 1, 0, dim[1] - 1, 0, dim[2] - 1);
>
>   double origin[3];
>   origin[0] = bounds[0] + spacing[0] / 2;
>   origin[1] = bounds[2] + spacing[1] / 2;
>   origin[2] = bounds[4] + spacing[2] / 2;
>   whiteImage->SetOrigin(origin);
>
> #if VTK_MAJOR_VERSION <= 5
>   whiteImage->SetScalarTypeToUnsignedChar();
>   whiteImage->AllocateScalars();
> #else
>   whiteImage->AllocateScalars(VTK_UNSIGNED_SHORT,1);
> #endif
>   // fill the image with foreground voxels:
>   unsigned char inval = 255; unsigned char outval = 0;
>   vtkIdType count = whiteImage->GetNumberOfPoints();
>   for (vtkIdType i = 0; i < count; ++i)
>     {
>     whiteImage->GetPointData()->GetScalars()->SetTuple1(i, inval);
>     }
>
>   // polygonal data --> image stencil:
>   vtkSmartPointer<vtkPolyDataToImageStencil> pol2stenc =
>     vtkSmartPointer<vtkPolyDataToImageStencil>::New();
> #if VTK_MAJOR_VERSION <= 5
>   pol2stenc->SetInput(pd);
> #else
>   pol2stenc->SetInputData(pd);
> #endif
>   pol2stenc->SetOutputOrigin(origin);
>   pol2stenc->SetOutputSpacing(spacing);
>   pol2stenc->SetOutputWholeExtent(whiteImage->GetExtent());
>   pol2stenc->Update();
>
>   vtkSmartPointer<vtkImplicitFunctionToImageStencil> func2stenc =
>   vtkImplicitFunctionToImageStencil::New();
>   //vtkSmartPointer<vtkElevationFilter> elev = vtkElevationFilter::New();
>   //elev->SetInput(pd);
>   //vtkSmartPointer<vtkImplicitDataSet> imp = vtkImplicitDataSet::New();
>   //imp->SetDataSet(elev->GetOutput());
>
>    //func2stenc->SetThreshold(0.1);
>   //func2stenc->SetInput(imp);
>   //func2stenc->SetOutputOrigin(origin);
>   //func2stenc->SetOutputSpacing(spacing);
>   //func2stenc->SetOutputWholeExtent(whiteImage->GetExtent());
>   //func2stenc->Update();
>
>   // cut the corresponding white image and set the background:
>   vtkSmartPointer<vtkImageStencil> imgstenc =
>     vtkSmartPointer<vtkImageStencil>::New();
> #if VTK_MAJOR_VERSION <= 5
>   imgstenc->SetInput(whiteImage);
>   imgstenc->SetStencil(pol2stenc->GetOutput());
>   //imgstenc->SetStencil(func2stenc->GetOutput());
> #else
>   imgstenc->SetInputData(whiteImage);
>   imgstenc->SetStencilConnection(pol2stenc->GetOutputPort());
>   //imgstenc->SetStencilConnection(func2stenc->GetOutputPort());
> #endif
>   //imgstenc->ReverseStencilOff();
>   imgstenc->SetBackgroundValue(outval);
>   imgstenc->Update();
>
>   vtkSmartPointer<vtkMetaImageWriter> writer =
>     vtkSmartPointer<vtkMetaImageWriter>::New();
>   writer->SetFileName("SphereVolume_p_w.mhd");
> #if VTK_MAJOR_VERSION <= 5
>   writer->SetInput(imgstenc->GetOutput());
> #else
>   writer->SetInputData(imgstenc->GetOutput());
> #endif
>   writer->Write();
>
>   return EXIT_SUCCESS;
> }
>
>
>
>
>
>>
>> Jothy
>>
>> On Mon, Mar 19, 2012 at 2:51 AM, Raghuram.O.S. <raghuramos1987 at gmail.com>wrote:
>>
>>> Hi,
>>>
>>> I have been trying to convert polydata to imagedata using the image
>>> stencil filter. I seem to be running into an issue of noise in the
>>> converted image. I get random triangles in the image which are pretty huge
>>> in the middle of actual data. I saw this post
>>> http://www.vtk.org/pipermail/vtkusers/2011-October/119302.html and
>>> tried using the implicit function. But, the post doesnt have a full example
>>> and there doesnt seem to be an example of
>>> vtkImplicitFunctionToImageStencil.
>>>
>>> My polydata doesnt seem to have any issues when I render it using
>>> polydatamapper. I have been using the example on the site at
>>> http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/PolyDataToImageData (as
>>> indicated in the previous post also).
>>> --
>>> Regards,
>>> Onti
>>>
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>>
>>
>> --
>> Jothy
>>
>>
>
>
> --
> Regards,
> Onti
>



-- 
Regards,
Onti
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