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;

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>