[Insight-developers] bug in BSplineDeformableTransform?

[Luis Ibanez]

Stefan, Tomas,

Thanks for pointing this out and for proposing
the fix.

We will take care of it before cutting ITK 3.6.


   Thanks


       Luis


---------------------
Tomáš Kazmar wrote:
> Hi Stefan,
> 
>  thanks for sending the link, I attached some more info to the bug 
> report and
> hopefully the right way to patch it.
> 
> Regards,
> Tomas
> 
> 
> # Hi Tomas,
> # # This seems to be the same problem as bug 4021, which i reported a 
> while ago.
> # # http://www.itk.org/Bug/view.php?id=4021
> # # Apparently it hasn't been fixed yet. :)
> # # Kind regards,
> # Stefan.
> # # At 23:12 18-3-2008, =?iso-8859-2?Q?Tom=E1=B9=20Kazmar?= wrote:
> # >Hi all,
> # >
> # >   recently i tried to use second order b-splines to warp images and
> # >the results contained sharp steps (~were not smooth). I am not sure
> # >whether I do something wrong. Has anybody used it successfully?
> # >
> # >It seems to me that there is an error in
> # >BSplineInterpolatingWeightFunction in combination with
> # >BSplineKernelFunction. The first uses kernel in the range -1..2 and
> # >the second defines the support as -1.5..1.5.
> # >
> # >Should I report it as a bug? There is a simple patch but once more
> # >I am not sure whether I use it the right way.
> # >
> # >Here is the relevant part of code:
> # >
> # >   const unsigned int SplineOrder = 2;
> # >   typedef itk::BSplineDeformableTransform<float, Dimension, 
> SplineOrder> # > TransformType;
> # >   TransformType::Pointer bsplineTransform = TransformType::New();
> # >   typedef TransformType::RegionType RegionType;
> # >   RegionType bsplineRegion;
> # >   RegionType::SizeType size;
> # >   const unsigned int nodesOutsideImage = SplineOrder;
> # >   const unsigned int nodesInsideImage = 4;
> # >   const unsigned int numberOfGridNodes = nodesInsideImage + # > 
> nodesOutsideImage;
> # >   size.Fill( numberOfGridNodes );
> # >   bsplineRegion.SetSize( size );
> # >   typedef TransformType::SpacingType SpacingType;
> # >   SpacingType spacing;
> # >   spacing[0] = 1.0 * floor( (width-1) / (double)(nodesInsideImage-1) );
> # >   spacing[1] = 1.0 * floor( (height-1) / 
> (double)(nodesInsideImage-1) );
> # >   typedef TransformType::OriginType OriginType;
> # >   OriginType origin;
> # >   origin[0] = 0.0 - spacing[0];
> # >   origin[1] = 0.0 - spacing[1];
> # >   bsplineTransform->SetGridSpacing( spacing );
> # >   bsplineTransform->SetGridOrigin( origin );
> # >   bsplineTransform->SetGridRegion( bsplineRegion );
> # >
> # >
> # >Regards,
> # >Tomas
> # >_______________________________________________
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