[Insight-developers] Bug 3647

[Jim Miller]

Karthik,

Dirk checked in the modifications to the Resample filter last week.  Can you
give it try to see if it addresses the issues you were having?

Jim

On 8/22/06, Karthik Krishnan <Karthik.Krishnan at kitware.com> wrote:
>
> Miller, James V (GE, Research) wrote:
>
> > Karthik,
> >
> > You checked some changes to ImageFunction and
> > LinearInterpolateImageFunction that I would like to discuss.
> >
> > Inside LinearInterpolateImageFunction you put in a call to
> > IsInsideBuffer().
> >
> I was worried about that, but given that there are several index
> calculations, multiplications for triliear interpolation etc, would 6
> inequality comparisons add much ?
>
> > The use case to date has been that it is the calling function's
> > responsibility to only evaluate the function at a pixel that is inside
> > the image.
> >
> > Also, you are caching the BufferedRegion as an ivar of the
> > ImageFunction.  There does not seem to be a reason for this as the
> > BufferedRegion should be available via an inline call on the image
> > itself (which the ImageFunction has access to).
> >
> The class has access to the image but is that an inlined call ?  The
> only reason, I was caching it as an ivar was that it would be used every
> call to EvaluateAtContinuousIndex().
>
> > Looking at the bug log, it looks like you were trying to address an
> > issue whereby the last slice of a resampled image would be blank.
> >
> Thanks. That was the exact issue I needed to address. We have been
> registering MR images with poor interslice resolution and very few
> slices to go with (8 slices) and discarding the border slices made it
> even thinner leaving very few features to guide the registration.
>
> The problem seemed to be one of the last slices not being considered
> inside the buffer, because of a tranform with a near zero z-translation.
>
> > Dirk Padfield has a fix for this particular problem.  The problem is
> > one of numerical precision, and samples that were supposed to be on
> > the last slice were numerically just a smidge past the last slice.
> > Dirk changed some of the calculations in the ResampleImageFilter to
> > use integral/fixed point arithmetic.  This fixed the problems he was
> > having with the ResampleImageFilter. I'll have a Dirk check in these
> > changes.
> >
> Thank you very much. If you are crunched for time checking in those
> changes etc, could you please mail the filter code.
>
> > *Jim Miller*
> > */_____________________________________/*
> > /Visualization & Computer Vision
> > GE Research
> > Bldg. KW, Room C223
> > 1 Research Circle, Schenectady NY 12309-1027
> >
> > _millerjv at research.ge.com <_//_mailto:millerjv at research.ge.com_//_>_/
> > /(518) 387-4005, Dial Comm: 8*833-4005/
> > /Cell: (518) 505-7065, Fax: (518) 387-6981/
> >
> >
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