vtk vtkPolyData 转 vtkImageData

 

 一、利用相应 api

// Convert the image to a polydata
  vtkNew<vtkImageDataGeometryFilter> imageDataGeometryFilter;
  imageDataGeometryFilter->SetInputConnection(source1->GetOutputPort());
  imageDataGeometryFilter->Update();

vtkNew<vtkImageToPolyDataFilter> filter;

    filter->SetInputConnection(reader->GetOutputPort());
    filter->SetOutputStyleToPolygonalize();
    filter->SetError(0);
    filter->DecimationOn();
    filter->SetDecimationError(0.0);
    filter->SetSubImageSize(25);
 
    vtkNew<vtkTriangleFilter> triFilter;
    triFilter->SetInputConnection(filter->GetOutputPort());
    vtkPolyData* poly = triFilter->GetOutput();

 二、自己处理实现

vtkSmartPointer<vtkImageData> polyDataToImageData(vtkSmartPointer<vtkPolyData> polydata)
  {
    vtkSmartPointer<vtkImageData> imageData = vtkSmartPointer<vtkImageData>::New();
    double bounds[6];
    polydata->GetBounds(bounds);
    double spacing[3]; // desired volume spacing
    spacing[0] = 0.5;
    spacing[1] = 0.5;
    spacing[2] = 0.5;
    imageData->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]));
    }
    imageData->SetDimensions(dim);
    imageData->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;
    imageData->SetOrigin(origin);

#if VTK_MAJOR_VERSION <= 5
    whiteImage->SetScalarTypeToUnsignedChar();
    whiteImage->AllocateScalars();
#else
    imageData->AllocateScalars(VTK_UNSIGNED_CHAR, 1);
#endif
    // fill the image with foreground voxels:
    unsigned char inval = 255;
    unsigned char outval = 0;
    vtkIdType count = imageData->GetNumberOfPoints();
    for (vtkIdType i = 0; i < count; ++i)
    {
      imageData->GetPointData()->GetScalars()->SetTuple1(i, inval);
    }

    //polygonal data --> image stencil:
    vtkSmartPointer<vtkPolyDataToImageStencil> pdtoImageStencil = vtkSmartPointer<vtkPolyDataToImageStencil>::New();
    pdtoImageStencil->SetInputData(polydata);
    pdtoImageStencil->SetOutputOrigin(origin);
    pdtoImageStencil->SetOutputSpacing(spacing);
    pdtoImageStencil->SetOutputWholeExtent(imageData->GetExtent());
    pdtoImageStencil->Update();

    //cut the corresponding white image and set the background:
    vtkSmartPointer<vtkImageStencil> imageStencil = vtkSmartPointer<vtkImageStencil>::New();
    imageStencil->SetInputData(imageData);
    imageStencil->SetStencilConnection(pdtoImageStencil->GetOutputPort());
    imageStencil->ReverseStencilOff();
    imageStencil->SetBackgroundValue(outval);
    imageStencil->Update();

    imageData->DeepCopy(imageStencil->GetOutput());
    return imageData;
  }