ITK/Examples/ImageProcessing/MergeLabelMapFilter

#include "itkBinaryImageToShapeLabelMapFilter.h"
#include "itkMergeLabelMapFilter.h"
 
int main(int argc, char* argv[])
{
  typedef itk::Image<int, 3> ImageType;
 
  //Binary Image to Shape Label Map. 
  typedef itk::BinaryImageToShapeLabelMapFilter<ImageType> BI2SLMType;
  typedef BI2SLMType::OutputImageType LabelMapType;
  typedef BI2SLMType::LabelObjectType LabelObjectType;
 
  typedef itk::MergeLabelMapFilter<LabelMapType> MergerType;
  MergerType::Pointer merger = MergerType::New();
  merger->SetMethod(MergerType::PACK);
 
  int noObjects = 4;
 
  for (int i = 1; i <= noObjects; i++)
    {
    LabelMapType::Pointer labelMap = LabelMapType::New();
    LabelObjectType::Pointer labelObject = LabelObjectType::New();
 
    labelObject->SetLabel(1);
    labelMap->AddLabelObject(labelObject);
    labelMap->Update();
 
    merger->SetInput(i - 1, labelMap);
    }
 
  merger->Update();
  std::cout << "number of objects:  "
      << merger->GetOutput()->GetNumberOfLabelObjects() << "\n";
  std::cout << "number of expected objects:  " << noObjects << "\n";
 
  return EXIT_SUCCESS;
}