[Insight-users] itkResampleImageFilter and transformation matrix
Gomez, Alberto
alberto.gomez at kcl.ac.uk
Tue Nov 9 09:24:03 EST 2010
Hello all,
I am resampling one volume (1) into another (2) to compare them. They
have different origin, orientation, etc. I can think of two ways of
achieving this, but only one works for me and I wonder why, maybe you
can help me.
1st way: Using itk::ResampleImageFIlter with no transformation, setting
useReferenceImageOn and using volume (2) as reference. This works fine.
2nd way: Not using reference image, but instead using a transformation
from volume(1) to volume(2). For some reason this does not work.
I obtain transformation matrix from the orientation and offset of each
image, and I am sure that both matrices (lets call them M1 and M2) are
correctly computed. What I do next is compute M = inv(M1)*M2
and transform image 1 through M (actually through its inverse, since the
transform operates from output to input). In addition I fix the output
spacing, origin, startindex and size to those of image (2) so that my
resulting transformed image is in the same space as the image (2) and i
can display both together.
My guess is that this does not work because even if I set
useReferenceImageOff(), the input orientation is taken into account and
therefor my matrix is not the right one...
Anyone can give any advice on this??
Thank you,
Alberto
--
Alberto Gomez
Division of Imaging Sciences
The Rayne Institute
4th Floor, Lambeth Wing
St Thomas' Hospital
London SE1 7EH
email: alberto.gomez at kcl.ac.uk
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