[Insight-users] Resample an image to a higher resolution in the same space with a zero derivative edge condition

[Kishore Mosaliganti]

Is this class relevant to your problem?

http://www.itk.org/Doxygen318/html/classitk_1_1ZeroFluxNeumannBoundaryCondition.html

Kishore

On Thu, Sep 23, 2010 at 5:42 PM, Seth Gilchrist <seth at mech.ubc.ca> wrote:
> Hello,
> I know what you are thinking...why are you up-sampling an image?  Here is
> the situation and problem and I hope that you can help.
>
> I have an image of vectors (3D image, 3D vectors) that is of a course
> resolution (35,20,20).  These vectors represent the displacement of a
> grouping of pixels in a fixed image. Each voxel in the vector image
> represents the average displacement of 21x21x21 voxels in the fixed image.
> What I want to do is linearly interpolate the data from the course vector
> image into the grid (they occupy the same space) of the fixed image.  The
> new vector image will then be used to morph the fixed image into the moving
> image space, giving a deformable-like transform, and then the fixed and
> moving image can be operated on in the same space.
>
> The problem is that when interpolating the values at the edge of the vector
> image the interpolator uses a single value for the out-of-bounds pixels.
> This means that the vectors at the edge of my new vector image converge to
> the displacement represented by the out-of-bounds value (a constant).  What
> I would like, is to have the edge given a zero derivative (Neumann)
> condition (or even better, be able to try a few different boundary
> conditions).  I have looked through the interpolate and resample filters and
> can't seem to find this already implemented.  Has this been done, or should
> I just get on writing it myself?
>
> Thanks for your time and help.
>
> Regards,
> Seth
>
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