[Insight-users] itk::BSplineDownsampleImageFilter

[Luis Ibanez]

Hi Jef,

Could you please describe in more detail what you mean by

                     "portraited half in Y -dimension?"

if you could post a screenshot that will be great.

It will help us a lot to track the potential source of the problem.

FYI, please note that one of the recent changes in ITK is that
the coordiantes of pixels are now copmuted consistently at the
center of the pixel. This applies to the BSpline Grids as well,
and had an impact on what gets to be considered to be inside
and outside of the image.

(this may or may not be related to the change in behavior that
you are observing...)



      Thanks


           Luis



------------------------------------------------------------------
On Thu, Feb 4, 2010 at 12:33 PM, jef vdmb <jvdmb at hotmail.com> wrote:
> Hi,
>
> I am using the bspline downsample filter in the 3.16 version
>
>      typedef itk::BSplineResampleImageFilterBase<InputImageType,
> InputImageType> ResamplerType;
>      typename itk::BSplineDownsampleImageFilter<
> InputImageType,InputImageType, ResamplerType >::Pointer df
>           = itk::BSplineDownsampleImageFilter<
> InputImageType,InputImageType, ResamplerType >::New();
>         df->SetSplineOrder(3);
>     df->SetInput(input);
>     df->Update();
>
> Unless I am using this filter incorrectly, it would seem that there is a
> problem with the filter. The output computed is wrong. The output image
> properties are set correctly (half the size, double the spacing,...) but the
> content of the original image is only portraited half in Y -dimension? This
> is not the case in the 3.8 version, the filter seems to have broken
> somewhere in between, probalby due to changes in the file
> itkBSplineResampleImageFilterBase.txx.
>
> The result is the same for all resampler types:
>
>     typedef itk::BSplineResampleImageFilterBase<InputImageType,
> InputImageType> ResamplerType;
>     typedef itk::BSplineCenteredResampleImageFilterBase<InputImageType,
> InputImageType> CenteredResamplerType;
>     typedef itk::BSplineL2ResampleImageFilterBase<InputImageType,
> InputImageType> L2ResamplerType;
>     typedef itk::BSplineCenteredL2ResampleImageFilterBase<InputImageType,
> InputImageType> CenteredL2ResamplerType;
>
> The Upsampler doesn't show the same issues, it works fine in both 3.16 and
> 3.8 versions.
>
> Regards,
> Jef
>
>
>
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