PolyDataToImageData
VTKExamples/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 vtkPolyDataToImageStencil is utilized. The resultant image is saved to disk in metaimage file format (SphereVolume.mhd).
Code
PolyDataToImageData.cxx
#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkPolyData.h>
#include <vtkImageData.h>
#include <vtkSphereSource.h>
#include <vtkMetaImageWriter.h>
#include <vtkPolyDataToImageStencil.h>
#include <vtkImageStencil.h>
#include <vtkPointData.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 *[])
{
vtkSmartPointer<vtkSphereSource> sphereSource =
vtkSmartPointer<vtkSphereSource>::New();
sphereSource->SetRadius(20);
sphereSource->SetPhiResolution(30);
sphereSource->SetThetaResolution(30);
vtkSmartPointer<vtkPolyData> pd = sphereSource->GetOutput();
sphereSource->Update();
vtkSmartPointer<vtkImageData> whiteImage =
vtkSmartPointer<vtkImageData>::New();
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);
#if VTK_MAJOR_VERSION <= 5
whiteImage->SetScalarTypeToUnsignedChar();
whiteImage->AllocateScalars();
#else
whiteImage->AllocateScalars(VTK_UNSIGNED_CHAR,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();
// 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());
#else
imgstenc->SetInputData(whiteImage);
imgstenc->SetStencilConnection(pol2stenc->GetOutputPort());
#endif
imgstenc->ReverseStencilOff();
imgstenc->SetBackgroundValue(outval);
imgstenc->Update();
vtkSmartPointer<vtkMetaImageWriter> writer =
vtkSmartPointer<vtkMetaImageWriter>::New();
writer->SetFileName("SphereVolume.mhd");
#if VTK_MAJOR_VERSION <= 5
writer->SetInput(imgstenc->GetOutput());
#else
writer->SetInputData(imgstenc->GetOutput());
#endif
writer->Write();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(PolyDataToImageData)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(PolyDataToImageData MACOSX_BUNDLE PolyDataToImageData.cxx)
target_link_libraries(PolyDataToImageData ${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 PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.