ITK/Examples/Iterators/ImageRegionIteratorWithIndex

This example demonstrates how to traverse an itkImage. This iterator varies from ImageRegionIterator in that it provides efficient access to the location (index) of the current pixel.

ImageRegionIteratorWithIndex.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileReader.h"
3. include "itkImageRegionIteratorWithIndex.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"

int main(int argc, char*argv[]) {

 if(argc < 2)
   {
   std::cerr << "Required: filename" << std::endl;
   return EXIT_FAILURE;
   }

 typedef itk::Image<unsigned char, 2>  ImageType;

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

 ImageType::Pointer image = reader->GetOutput();
 
 ImageType::SizeType regionSize;
 regionSize[0] = 5;
 regionSize[1] = 4;

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

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

 itk::ImageRegionIteratorWithIndex<ImageType> imageIterator(image,image->GetLargestPossibleRegion());

 while(!imageIterator.IsAtEnd())
   {
   std::cout << "Index: " << imageIterator.GetIndex() << " value: " << imageIterator.Get() << std::endl;
 
   // Set the current pixel to white
   imageIterator.Set(255);
   
   ++imageIterator;
   }

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

 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;

}

</source>

CMakeLists.txt

<source lang="cmake"> cmake_minimum_required(VERSION 2.6)

PROJECT(ImageRegionIteratorWithIndex)

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(ImageRegionIteratorWithIndex ImageRegionIteratorWithIndex.cxx) TARGET_LINK_LIBRARIES(ImageRegionIteratorWithIndex vtkHybrid ITKNumerics ITKBasicFilters ITKCommon ITKIO)

</source>