[Insight-users] Making a deformation field denser in order to deform points

[Yago Diez]

Hi everyone,

I have a problem regarding itk deformation fields:

Specifically, I want to know where a particular point ends up after
registration. Said registration has produced a deformation field. I have
already used this deformation field to deform the source image and produce
the output image for registration (this was done using itkWarpImageFilter).

My problem is that at this moment I only want to transform one point. The
obvious solution was to read the corresponding voxel in the deformation
field and add it to the point, but the problem is that the deformation
field is not "dense enough", so in most cases, the read deformation for a
point ends up being zero (see attached image for a screen capture of a 2D
slice of my 3D deformation field).

 I have noticed how when I deform an image with itkWarpImageFilter, there
is an "extra" interpolation step which would avoid the problem I am having,
but so far I have not been able to interpolate a deformation field. Any
ideas on how to do that?

Thank you




Yago Diez Donoso (PhD)
Computer Vision and Robotics Group http://vicorob.udg.es/
E-mail: yago at eia.udg.es; yagodiezdonoso at gmail.com
Phone: (int. code) 34 972418013
University of Girona
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