ITK/Examples/ImageProcessing/ConnectedComponentImageFilter

ConnectedComponentImageFilter.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileWriter.h"
3. include "itkConnectedComponentImageFilter.h"
4. include "itkRescaleIntensityImageFilter.h"

1. include "itkImageToVTKImageFilter.h"

1. include "vtkImageViewer.h"
2. include "vtkRenderWindowInteractor.h"
3. include "vtkSmartPointer.h"
4. include "vtkImageActor.h"
5. include "vtkInteractorStyleImage.h"
6. 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);
     }
   }

} </source>

CMakeLists.txt

<source lang="cmake"> 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)

</source>