Hi SPM users,
I'm doing affine registration of the 3D data to the atlas. The 3D data sets and the atlas have different resolutions and dimensions. I get the mat file with VG (atlas), VF (input data) and Affine matrix, when I do the spm_imatrix(Affine) and apply the translations, rotations and scales directly to the image (VF) using reorient, I don't see the correct results. Is the affine matrix in the mat file dependent on the parameters in VG, VF?
I saw the description in the spm_affreg script that voxels in VF (input data) map to those in VG (atlas template) by VG.mat\M*VF.mat. I even tried this Pure_affine = VG.mat\Affine*VF.mat and tried to apply the resulting translations, rotations and scales to the image (VF) using reorient, but I don't see the correct results.
I think I'm doing somethin wrong. Please let me know if anyone knows how to extract the pure transformation parameters that are independent.
Thank you very much for your time and patience,
Aaryani
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