this is the response that I hoped to receive,but I have some questions:
1)If I put vecreg in place of applywarp, the script give me the components
V1, V2, V3 of the new space?
Because I thought to start with vecreg to warp single vectors (V1, V2,V3 of
study 1;V1,V2,V3 of study 2 ...)in the new space and then calculate a "kind
of media" to get the triad final vector V1, V2,V3.
2)Can you write an example for L1,V1 in practical way, thanks!
>I see now.
>You can reconstruct a tensor from its decomposition using the
>formula: Tensor = sum( Li * Vi * Vi')
>This can be implemented easily using several calls to fslmaths (after
>splitting the vectors into x,y,z components using fslsplit).
>Note that you cannot use tbss_non_FA directly on vector images such as
>V1 etc. You will need to edit the tbss_non_FA script, and use vecreg
>instead of applywarp. Vecreg will apply a local rotation to the
>vectors that is induced by the warpfield.