[Insight-users] Help with moving NeighborhoodIterator with an offset

[Matt McCormick]

Hi Anna,

You want to look at how ImageBoundaryFacesCalculator is used:

http://www.itk.org/Doxygen/html/structitk_1_1NeighborhoodAlgorithm_1_1ImageBoundaryFacesCalculator.html

Create one, then only iterate on region 0.

Matt

On Mon, Dec 5, 2011 at 10:57 AM, anna han wan <anna.han.wan at gmail.com> wrote:
> Hi all,
>
> I am using NeighborhoodIterator to visit all voxels of my image(3D) and to
> do some processing within a rectangular neighborhood. As doing this is a
> time consuming process, I decided to move the iterator with an offset rather
> than visiting every voxel. When I run my code I got the following error:
>
>
>
> Unhandled exception at 0x000007fefcceaa7d in main.exe: Microsoft C++
> exception: itk::ExceptionObject at memory location 0x00b4f4a8.
>
>
>
> This is because the iterator has reached the image border. So my question is
> how can I increment the ierator with an offset and check at the same time if
> I reched the image border?  I find the function InBounds but I don’t know
> how to use it properly?
>
>
>
>
>
>
>
>
>
> The relevent part of my code that the error is related to is as follows:
>
>
>
> typedef itk::NeighborhoodIterator<ImageType> NeighborhoodIteratorType;
>
> NeighborhoodIteratorType It(radius, image,region);
>
> It.NeedToUseBoundaryConditionOff();
>
>
>
> NeighborhoodIteratorType::OffsetType ItOffset;
>
> ItOffset.Fill(2);
>
>
>
>
>
>       for ( It.GoToBegin(); !It.IsAtEnd();  It += ItOffset)
>
>       {
>
>
>
>             sum=0;
>
>             for(i = 0; i < It.Size(); i++)
>
>             {
>
>               if (It.GetPixel(i)>0)
>
>                     sum=sum+1;
>
>             }
>
>
>
>       }
>
>
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