ITK  5.0.0
Insight Segmentation and Registration Toolkit
WikiExamples/ImageSegmentation/LabelImageToLabelMapFilter.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 ConnectedComponentImageFilterType = itk::ConnectedComponentImageFilter <ImageType, ImageType >;
ConnectedComponentImageFilterType::Pointer connectedComponentImageFilter
= ConnectedComponentImageFilterType::New ();
connectedComponentImageFilter->SetInput(image);
connectedComponentImageFilter->Update();
using LabelImageToLabelMapFilterType = itk::LabelImageToLabelMapFilter <ImageType>;
LabelImageToLabelMapFilterType::Pointer labelImageToLabelMapFilter
= LabelImageToLabelMapFilterType::New ();
labelImageToLabelMapFilter->SetInput(connectedComponentImageFilter->GetOutput());
labelImageToLabelMapFilter->Update();
// The output of this filter is an itk::LabelMap, which contains itk::LabelObject's
std::cout << "There are " << labelImageToLabelMapFilter->GetOutput()->GetNumberOfLabelObjects() << " objects." << std::endl;
return EXIT_SUCCESS;
}
void CreateImage(ImageType::Pointer image)
{
// Create an image with 2 connected components
start[0] = 0;
start[1] = 0;
unsigned int NumRows = 200;
unsigned int NumCols = 300;
size[0] = NumRows;
size[1] = NumCols;
region.SetSize(size);
region.SetIndex(start);
image->SetRegions(region);
image->Allocate();
// Make a square
for(unsigned int r = 20; r < 80; r++)
{
for(unsigned int c = 30; c < 100; c++)
{
pixelIndex[0] = r;
pixelIndex[1] = c;
image->SetPixel(pixelIndex, 255);
}
}
// Make another square
for(unsigned int r = 100; r < 130; r++)
{
for(unsigned int c = 115; c < 160; c++)
{
pixelIndex[0] = r;
pixelIndex[1] = c;
image->SetPixel(pixelIndex, 255);
}
}
}