Dear SPM,
I am a new user in SPM for spatial normalization. Currently I am trying
to find the six parameters for the rigid body transformation. There are
two ways I had explored, spm_coreg and coregister in GUI. The result
from spm_coreg and the one from the unix window by running GUI are the
same. However in GUI, the output dindow print out the transformation
matrix. How Xo, Yo, Zo transformed to X1, Y1, Z1. So I use spm_imatrix
to convert the matrix into parameters. But I get 12 parameters for affine
transformation. I wonder if the GUI is using affine tranformation or
rigid body transformation. I wonder if the result is due to the fact that
spm_imatrix is under the affine model. And I would like to know if there
are any other spm matlab command that can transform the matrix of
coregister from GUI output window to six parameters of rigid body
transformation?
Another question is about the output of spm_coreg. Is there any way to
find out which value represents x-shift, y-shift, z-shift, pitch, row and
yaw? And what unit they are in (mm, voxel or other unit for shifts and
degree or radian for roation)?
Thank you so much.
Helen
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