ITK  5.0.0
Insight Segmentation and Registration Toolkit
WikiExamples/ImageProcessing/BinaryImageToLabelMapFilter.cxx
#include "itkImage.h"
using ImageType = itk::Image<unsigned char, 2>;
static void CreateImage(ImageType::Pointer image);
int main(int, char *[])
{
ImageType::Pointer image = ImageType::New();
CreateImage(image);
using BinaryImageToLabelMapFilterType = itk::BinaryImageToLabelMapFilter<ImageType>;
BinaryImageToLabelMapFilterType::Pointer binaryImageToLabelMapFilter = BinaryImageToLabelMapFilterType::New();
binaryImageToLabelMapFilter->SetInput(image);
binaryImageToLabelMapFilter->Update();
// The output of this filter is an itk::LabelMap, which contains itk::LabelObject's
std::cout << "There are " << binaryImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects() << " objects." << std::endl;
// Loop over each region
for(unsigned int i = 0; i < binaryImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects(); i++)
{
// Get the ith region
BinaryImageToLabelMapFilterType::OutputImageType::LabelObjectType* labelObject = binaryImageToLabelMapFilter->GetOutput()->GetNthLabelObject(i);
// Output the pixels composing the region
for(unsigned int pixelId = 0; pixelId < labelObject->Size(); pixelId++)
{
std::cout << "Object " << i << " contains pixel " << labelObject->GetIndex(pixelId) << std::endl;
}
}
return EXIT_SUCCESS;
}
void CreateImage(ImageType::Pointer image)
{
// Create a black image with a white square
start.Fill(0);
size.Fill(20);
region.SetSize(size);
region.SetIndex(start);
image->SetRegions(region);
image->Allocate();
itk::ImageRegionIterator<ImageType> imageIterator(image,image->GetLargestPossibleRegion());
// Make a square
while(!imageIterator.IsAtEnd())
{
if((imageIterator.GetIndex()[0] > 5 && imageIterator.GetIndex()[0] < 10) &&
(imageIterator.GetIndex()[1] > 5 && imageIterator.GetIndex()[1] < 10) )
{
imageIterator.Set(255);
}
else
{
imageIterator.Set(0);
}
++imageIterator;
}
WriterType::Pointer writer = WriterType::New();
writer->SetFileName("image.png");
writer->SetInput(image);
writer->Update();
}