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PolyDataToImageData

vtk-examples/Cxx/PolyData/PolyDataToImageData

Description

  • Contributed by: Lars Friedrich

This example generates a sphere (prerequisite: closed surface of type vtkPolyData) and converts it into volume representation (vtkImageData) where the foreground voxels are 255 (inside) and the background voxels are 0 (outside). Internally [vtkPolyData](https://www.vtk.org/doc/nightly/html/classvtkPolyData.html#details)ToImageStencil is utilized. The resultant image is saved to disk in metaimage file format (SphereVolume.mhd).

Question

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Code

PolyDataToImageData.cxx

#include <vtkImageData.h>
#include <vtkImageStencil.h>
#include <vtkMetaImageWriter.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyDataToImageStencil.h>
#include <vtkSphereSource.h>

/**
 * This program generates a sphere (closed surface, vtkPolyData) and converts it
 * into volume representation (vtkImageData) where the foreground voxels are 1
 * and the background voxels are 0. Internally vtkPolyDataToImageStencil is
 * utilized. The resultant image is saved to disk in metaimage file format
 * (SphereVolume.mhd).
 */
int main(int, char*[])
{
  vtkNew<vtkSphereSource> sphereSource;
  sphereSource->SetRadius(20);
  sphereSource->SetPhiResolution(30);
  sphereSource->SetThetaResolution(30);
  auto pd = sphereSource->GetOutput();
  sphereSource->Update();

  vtkNew<vtkImageData> whiteImage;
  double bounds[6];
  pd->GetBounds(bounds);
  double spacing[3]; // desired volume spacing
  spacing[0] = 0.5;
  spacing[1] = 0.5;
  spacing[2] = 0.5;
  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);
  whiteImage->AllocateScalars(VTK_UNSIGNED_CHAR, 1);

  // 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:
  vtkNew<vtkPolyDataToImageStencil> pol2stenc;
  pol2stenc->SetInputData(pd);
  pol2stenc->SetOutputOrigin(origin);
  pol2stenc->SetOutputSpacing(spacing);
  pol2stenc->SetOutputWholeExtent(whiteImage->GetExtent());
  pol2stenc->Update();

  // Cut the corresponding white image and set the background:
  vtkNew<vtkImageStencil> imgstenc;
  imgstenc->SetInputData(whiteImage);
  imgstenc->SetStencilConnection(pol2stenc->GetOutputPort());
  imgstenc->ReverseStencilOff();
  imgstenc->SetBackgroundValue(outval);
  imgstenc->Update();

  vtkNew<vtkMetaImageWriter> writer;
  writer->SetFileName("SphereVolume.mhd");
  writer->SetInputData(imgstenc->GetOutput());
  writer->Write();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(PolyDataToImageData)

find_package(VTK COMPONENTS 
  CommonCore
  CommonDataModel
  FiltersSources
  IOImage
  ImagingStencil
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "PolyDataToImageData: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(PolyDataToImageData MACOSX_BUNDLE PolyDataToImageData.cxx )
  target_link_libraries(PolyDataToImageData PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS PolyDataToImageData
  MODULES ${VTK_LIBRARIES}
)

Download and Build PolyDataToImageData

Click here to download PolyDataToImageData and its CMakeLists.txt file. Once the tarball PolyDataToImageData.tar has been downloaded and extracted,

cd PolyDataToImageData/build

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./PolyDataToImageData

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.