Iterate Region In Image With Neighborhood

Synopsis

Iterate over a region of an image with a neighborhood (with write access).

Results

../../../../_images/Yinyang5.png

Yinyang.png

../../../../_images/IterateRegionWithWriteAccess.png

Yinyang.png In VTK Window

Output:

An extensive list of the neighborhood will be printed to the screen.

Code

C++

#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkNeighborhoodIterator.h"

#include <itkImageToVTKImageFilter.h>

#include "vtkVersion.h"
#include "vtkImageViewer.h"
#include "vtkImageMapper3D.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkSmartPointer.h"
#include "vtkImageActor.h"
#include "vtkInteractorStyleImage.h"
#include "vtkRenderer.h"

int
main(int argc, char * argv[])
{
  if (argc < 2)
  {
    std::cerr << "Required: filename" << std::endl;
    return EXIT_FAILURE;
  }

  using ImageType = itk::Image<unsigned char, 2>;

  using ReaderType = itk::ImageFileReader<ImageType>;
  ReaderType::Pointer reader = ReaderType::New();
  reader->SetFileName(argv[1]);
  reader->Update();

  ImageType::Pointer image = reader->GetOutput();

  ImageType::SizeType regionSize;
  regionSize[0] = 50;
  regionSize[1] = 1;

  ImageType::IndexType regionIndex;
  regionIndex[0] = 0;
  regionIndex[1] = 0;

  ImageType::RegionType region;
  region.SetSize(regionSize);
  region.SetIndex(regionIndex);

  ImageType::SizeType radius;
  radius[0] = 1;
  radius[1] = 1;

  itk::NeighborhoodIterator<ImageType> iterator(radius, image, region);


  while (!iterator.IsAtEnd())
  {
    // Set the current pixel to white
    iterator.SetCenterPixel(255);

    for (unsigned int i = 0; i < 9; i++)
    {
      ImageType::IndexType index = iterator.GetIndex(i);
      std::cout << index[0] << " " << index[1] << std::endl;

      bool IsInBounds;
      iterator.GetPixel(i, IsInBounds);
      if (IsInBounds)
      {
        iterator.SetPixel(i, 255);
      }
    }
    ++iterator;
  }

  // Visualize
  using ConnectorType = itk::ImageToVTKImageFilter<ImageType>;
  ConnectorType::Pointer connector = ConnectorType::New();
  connector->SetInput(image);

  vtkSmartPointer<vtkImageActor> actor = vtkSmartPointer<vtkImageActor>::New();
#if VTK_MAJOR_VERSION <= 5
  actor->SetInput(connector->GetOutput());
#else
  connector->Update();
  actor->GetMapper()->SetInputData(connector->GetOutput());
#endif

  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;
}

Classes demonstrated