[Insight-users] ShapedNeighborhoodIterator: how to get indexes and how to check bounds?

[Hugues Fontenelle]

Dear all,

 

It is my first post on the list and perhaps my question has already been
answered previously, albeit I couldn't find where. I'd be glad if you could
help even with a link.

I'm implementing a filter similar to the one found in
Examples\Iterators\ShapedNeighborhoodIterators1.cxx

 

[1] I understand that the advantage of the
NeighborhoodAlgorithm::ImageBoundaryFacesCalculator is to lighten the burden
of the algorithm where no check for bounds is necessary.

However in the (inner) loop of the ShapedNeighborhoodIterator, no bounds are
checked; instead all neighbors are visited (even those falling outside of
the image).

How can I check for this?

 

[2] In the (inner) loop of the ShapedNeighborhoodIterator, I can get the
values of the pixels with ci.Get() .

How can I get the indexes? The GetIndex method does not work.

 

Thank you for your time,

 

Hugues

 

Here is my code:

 

  typedef itk::ShapedNeighborhoodIterator< ImageType >
ShapedNeighborhoodIteratorType;

  ShapedNeighborhoodIteratorType::OffsetType top = {{0,-1}};

  ShapedNeighborhoodIteratorType::OffsetType bottom = {{0,1}};

  ShapedNeighborhoodIteratorType::OffsetType left = {{-1,0}};

  ShapedNeighborhoodIteratorType::OffsetType right = {{1,0}};

  ShapedNeighborhoodIteratorType::RadiusType radius;

  radius.Fill( 1 );

 

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

  FaceCalculatorType faceCalculator;

  FaceCalculatorType::FaceListType faceList;

  FaceCalculatorType::FaceListType::iterator faceListIterator;

  faceList = faceCalculator( inputImage, inputImage->GetRequestedRegion(),
radius );

 

  for ( faceListIterator=faceList.begin(); faceListIterator !=
faceList.end(); ++faceListIterator)

  {

    std::cout << "Face group" << std::endl;

 

    ShapedNeighborhoodIteratorType it( radius, reader->GetOutput(),
*faceListIterator );

 

    for (it.GoToBegin(); !it.IsAtEnd(); ++it)

    {

      std::cout << "Centre index: " << it.GetIndex() << std::endl;

 

      it.ActivateOffset(top);

      it.ActivateOffset(bottom);

      it.ActivateOffset(left);

      it.ActivateOffset(right);

 

      ShapedNeighborhoodIteratorType::ConstIterator ci;

 

      std::cout << "  Neighbor values: ";

      for (ci = it.Begin(); ci != it.End(); ci++)

      {

        std::cout << ci.Get() << " "; // All neighbors visited?!?, How to
GetIndex() ?!?

      }

      std::cout << std::endl;

    }

  }

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