ITK/Examples/ImageProcessing/ConnectedComponentImageFilter

ConnectedComponentImageFilter.cxx

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkConnectedComponentImageFilter.h"
#include "itkRescaleIntensityImageFilter.h"

#include "itkImageToVTKImageFilter.h"

#include "vtkImageViewer.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkSmartPointer.h"
#include "vtkImageActor.h"
#include "vtkInteractorStyleImage.h"
#include "vtkRenderer.h"
 
typedef itk::Image<unsigned char, 2>  ImageType;

static void CreateImage(ImageType::Pointer image);

int main( int argc, char *argv[])
{
  ImageType::Pointer image = ImageType::New();
  CreateImage(image);

  typedef itk::ConnectedComponentImageFilter <ImageType, ImageType >
    ConnectedComponentImageFilterType;

  ConnectedComponentImageFilterType::Pointer labelFilter
    = ConnectedComponentImageFilterType::New ();
  labelFilter->SetInput(image);
  labelFilter->Update();

  typedef itk::RescaleIntensityImageFilter< ImageType, ImageType > RescaleFilterType;
  RescaleFilterType::Pointer rescaleFilter = RescaleFilterType::New();
  rescaleFilter->SetOutputMinimum(0);
  rescaleFilter->SetOutputMaximum(255);
  rescaleFilter->SetInput(labelFilter->GetOutput());

  typedef itk::ImageToVTKImageFilter<ImageType> ConnectorType;
  ConnectorType::Pointer originalConnector = ConnectorType::New();
  
  originalConnector->SetInput(image);

  vtkSmartPointer<vtkImageActor> originalActor =
    vtkSmartPointer<vtkImageActor>::New();
  originalActor->SetInput(originalConnector->GetOutput());

  ConnectorType::Pointer labelConnector = ConnectorType::New();
  labelConnector->SetInput(rescaleFilter->GetOutput());
  
  vtkSmartPointer<vtkImageActor> labelActor =
    vtkSmartPointer<vtkImageActor>::New();
  labelActor->SetInput(labelConnector->GetOutput());

  // There will be one render window
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->SetSize(600, 300);

  vtkSmartPointer<vtkRenderWindowInteractor> interactor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);

  // Define viewport ranges
  // (xmin, ymin, xmax, ymax)
  double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
  double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

  // Setup both renderers
  vtkSmartPointer<vtkRenderer> leftRenderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(leftRenderer);
  leftRenderer->SetViewport(leftViewport);
  leftRenderer->SetBackground(.6, .5, .4);

  vtkSmartPointer<vtkRenderer> rightRenderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(rightRenderer);
  rightRenderer->SetViewport(rightViewport);
  rightRenderer->SetBackground(.4, .5, .6);

  // Add the sphere to the left and the cube to the right
  leftRenderer->AddActor(originalActor);
  rightRenderer->AddActor(labelActor);

  leftRenderer->ResetCamera();
  rightRenderer->ResetCamera();

  renderWindow->Render();

  vtkSmartPointer<vtkInteractorStyleImage> style =
    vtkSmartPointer<vtkInteractorStyleImage>::New();

  interactor->SetInteractorStyle(style);

  interactor->Start();
  
  return EXIT_SUCCESS;
}

void CreateImage(ImageType::Pointer image)
{
  // Create an image with 2 connected components
  ImageType::RegionType region;
  ImageType::IndexType start;
  start[0] = 0;
  start[1] = 0;

  ImageType::SizeType size;
  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++)
      {
      ImageType::IndexType pixelIndex;
      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++)
      {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;

      image->SetPixel(pixelIndex, 255);
      }
    }
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)

PROJECT(ConnectedComponents)

include_directories(/home/doriad/src/ITK/Wrapping/WrapITK/ExternalProjects/ItkVtkGlue/src/)

FIND_PACKAGE(VTK REQUIRED)
INCLUDE(${VTK_USE_FILE})

FIND_PACKAGE(ITK REQUIRED)
INCLUDE(${ITK_USE_FILE})

ADD_EXECUTABLE(ConnectedComponents ConnectedComponents.cpp)
TARGET_LINK_LIBRARIES(ConnectedComponents
vtkHybrid
ITKBasicFilters ITKCommon ITKIO)