ITK/Examples/Images/NeighborhoodOperatorImageFilter

NeighborhoodOperatorImageFilter.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkNeighborhoodOperatorImageFunction.h"
3. include "itkNeighborhoodOperator.h"
4. include "itkNeighborhoodAllocator.h"
5. include "itkNeighborhoodOperatorImageFilter.h"
6. 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<float, 2> FloatImageType;

void CreateImage(FloatImageType::Pointer image);

class CustomOperator

public itk::NeighborhoodOperator<float, 2>

{

 // Count the number of valid neighbors and set the output pixel to that number.
 // What we should see is that the number of neighbors is constant in the "middle"
 // of the image and the number of neighbors is fewer on the edges.

 protected:
   CoefficientVector GenerateCoefficients();

   void Fill(const CoefficientVector &coeff)
   {
     //Superclass::FillCenteredDirectional(coeff);
   }

};

CustomOperator::CoefficientVector CustomOperator::GenerateCoefficients() {

 std::cout << "Neighborhood size: " << this->GetSize() << std::endl;
 /*
 for(unsigned int i = 0; i < this->GetSize(); i++)
   {
   ImageType::PixelType pixel = this->GetElement(i);
   std::cout << "Pixel " << i << " : " << pixel << std::endl;
   }
 */

}

int main(int, char*[]) {

 FloatImageType::Pointer image = FloatImageType::New();
 CreateImage(image);

 CustomOperator customOperator;
 
 itk::NeighborhoodOperatorImageFilter<FloatImageType, FloatImageType>::Pointer filter
       = itk::NeighborhoodOperatorImageFilter<FloatImageType, FloatImageType>::New();
 filter->SetOperator(customOperator);
 filter->SetInput(image);
 filter->Update();
 
 // Visualize
 typedef itk::RescaleIntensityImageFilter< FloatImageType, itk::Image<unsigned char, 2> > RescaleFilterType;
 RescaleFilterType::Pointer rescaleFilter = RescaleFilterType::New();
 rescaleFilter->SetInput(filter->GetOutput());
 rescaleFilter->SetOutputMinimum(0);
 rescaleFilter->SetOutputMaximum(255);
 
 typedef itk::ImageToVTKImageFilter<itk::Image<unsigned char, 2> > ConnectorType;
 ConnectorType::Pointer connector = ConnectorType::New();
 connector->SetInput(rescaleFilter->GetOutput());

 vtkSmartPointer<vtkImageActor> actor =
   vtkSmartPointer<vtkImageActor>::New();
 actor->SetInput(connector->GetOutput());

 vtkSmartPointer<vtkRenderWindow> renderWindow =
   vtkSmartPointer<vtkRenderWindow>::New();

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

 vtkSmartPointer<vtkRenderer> renderer =
   vtkSmartPointer<vtkRenderer>::New();
 renderWindow->AddRenderer(renderer);

 renderer->AddActor(actor);
 renderer->ResetCamera();

 renderWindow->Render();

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

 interactor->SetInteractorStyle(style);

 interactor->Start();

 return EXIT_SUCCESS;

}

void CreateImage(FloatImageType::Pointer image) {

 // Create an image with 2 connected components
 FloatImageType::RegionType region;
 FloatImageType::IndexType start;
 start[0] = 0;
 start[1] = 0;

 FloatImageType::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 = 20; c < 80; c++)
       {
       FloatImageType::IndexType pixelIndex;
       pixelIndex[0] = r;
       pixelIndex[1] = c;

       image->SetPixel(pixelIndex, 15);
       }
   }

} </source>

CMakeLists.txt

<syntaxhighlight lang="cmake"> cmake_minimum_required(VERSION 3.9.5)

project(NeighborhoodOperatorImageFilter)

find_package(ITK REQUIRED) include(${ITK_USE_FILE}) if (ITKVtkGlue_LOADED)

 find_package(VTK REQUIRED)
 include(${VTK_USE_FILE})

else()

 find_package(ItkVtkGlue REQUIRED)
 include(${ItkVtkGlue_USE_FILE})
 set(Glue ItkVtkGlue)

endif()

add_executable(NeighborhoodOperatorImageFilter MACOSX_BUNDLE NeighborhoodOperatorImageFilter.cxx) target_link_libraries(NeighborhoodOperatorImageFilter

 ${Glue}  ${VTK_LIBRARIES} ${ITK_LIBRARIES})

</syntaxhighlight>

Download and Build NeighborhoodOperatorImageFilter

Click here to download NeighborhoodOperatorImageFilter. and its CMakeLists.txt file. Once the tarball NeighborhoodOperatorImageFilter.tar has been downloaded and extracted,

cd NeighborhoodOperatorImageFilter/build 

• If ITK is installed:

cmake ..

• If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:

cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project,

make

and run it:

./NeighborhoodOperatorImageFilter

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK and ITK bin directories to your path. This will resolve the VTK and ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.

ItkVtkGlue

ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.