ITK/Examples/Iterators/ShapedNeighborhoodIteratorManual

ShapedNeighborhoodIterator.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkShapedNeighborhoodIterator.h"
3. include "itkImageRegionIterator.h"
4. include "itkNeighborhoodAlgorithm.h"

// Notice that char type pixel values will not appear // properly on the command prompt therefore for the // demonstration purposes it is best to use the int // type, however in real applications iterators have // no problems with char type images. //typedef itk::Image<unsigned char, 2> ImageType; typedef itk::Image<unsigned int, 2> ImageType;

void CreateImage(ImageType::Pointer image);

int main(int, char*[]) {

 ImageType::Pointer image = ImageType::New();
 CreateImage(image);
 ImageType::SizeType radius;
 radius[0] = 1;
 radius[1] = 1;

 typedef itk::ShapedNeighborhoodIterator<ImageType> IteratorType;

 IteratorType::OffsetType top = Template:0,-1;
 IteratorType::OffsetType bottom = Template:0,1;
 IteratorType::OffsetType left = Template:-1,0;
 IteratorType::OffsetType right = Template:1,0;
 IteratorType::OffsetType center = Template:0,0;

 typedef itk::NeighborhoodAlgorithm
   ::ImageBoundaryFacesCalculator< ImageType > FaceCalculatorType;

 FaceCalculatorType faceCalculator;
 FaceCalculatorType::FaceListType faceList;
 faceList = faceCalculator(image, image->GetLargestPossibleRegion(),
                           radius);
 FaceCalculatorType::FaceListType::iterator faceListIterator;

 for ( faceListIterator=faceList.begin(); faceListIterator != faceList.end(); ++faceListIterator)
   {
   IteratorType iterator(radius, image, *faceListIterator);
   iterator.ActivateOffset(top);
   iterator.ActivateOffset(bottom);
   iterator.ActivateOffset(left);
   iterator.ActivateOffset(right);
   iterator.ActivateOffset(center);

   for(iterator.GoToBegin(); !iterator.IsAtEnd(); ++iterator) // Crashes here!
     {
     // The method for accessing pixel values using neighborhood
     // iterators is GetPixel(offset).
     std::cout << "top: " << iterator.GetPixel(top) << std::endl;
     std::cout << "bottom: " << iterator.GetPixel(bottom) << std::endl;
     std::cout << "left: " << iterator.GetPixel(left) << std::endl;
     std::cout << "right: " << iterator.GetPixel(right) << std::endl;
     /*
     std::cout << "top: " << iterator[top] << std::endl;
     std::cout << "bottom: " << iterator[bottom] << std::endl;
     std::cout << "left: " << iterator[left] << std::endl;
     std::cout << "right: " << iterator[right] << std::endl;
     */
     }
   }

 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;
 size[0] = 100;
 size[1] = 200;

 region.SetSize(size);
 region.SetIndex(start);

 image->SetRegions(region);
 image->Allocate();

 itk::ImageRegionIterator<ImageType> imageIterator(image,region);

 while(!imageIterator.IsAtEnd())
   {
   imageIterator.Set(0);

   ++imageIterator;
   }

} </source>

CMakeLists.txt

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

project(ShapedNeighborhoodIterator)

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

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

endif()

add_executable(ShapedNeighborhoodIterator MACOSX_BUNDLE ShapedNeighborhoodIterator.cxx)

if( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(ShapedNeighborhoodIterator ITKReview ${ITK_LIBRARIES})

else( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(ShapedNeighborhoodIterator ${ITK_LIBRARIES})

endif( "${ITK_VERSION_MAJOR}" LESS 4 )

</syntaxhighlight>

Download and Build ShapedNeighborhoodIterator

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

cd ShapedNeighborhoodIterator/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:

./ShapedNeighborhoodIterator

WINDOWS USERS PLEASE NOTE: Be sure to add the ITK bin directory to your path. This will resolve the 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.