Hi Kamran,
> i calculated the jacobian determinant after deformation, i want to know
> what it mean if i have for example 1.5 or 0.7 on the determinante?
It's the local volume change factor at that voxel. So 1.5 means that
voxel has 50% larger volume in the target (or possibly source... you'd
have to check the convention for how you computed the Jacobian from
the deformation field -- which maps source to target, but is defined
over the domain of the target voxels).
> ...
> and how i can calculate the mean of deformation vector?
If all your deformation fields are defined over the same target (e.g.
a template), then simply taking the mean (e.g. with imcalc) might be
what you want to do. However, arithmetic averaging of "large"
deformations might not be what you want; see the following paper for
discussion of this issue (not an easy read though, I'm afraid, in my
opinion anyway...)
http://dx.doi.org/10.1016/j.neuroimage.2004.07.068
Best,
Ged.
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