convert warp file from AFNI FSL

AFNI version info (afni -ver): Version AFNI_22.0.09 'Hadrian'

I have a2b.1D and a2b+orig. files generated from
How can I convert these files to be recognized by FSL's commands?

Thank you very much.

Copying a BRIK/HEAD file is as easy as:

3copy a2b+orig a2b.nii.gz

for example.

The affine transformation format is pretty different between the two software. I don't know of a simple way to do that.


Thanks for your suggestion .
I have tried this.
When I used FSL command (applywarp) to apply it, the error was reported:
'An error occured while reading file: a2b.nii'

Hi, Ashley-

Could you please copy+paste your command?

I don't think outputs a warp dataset---that would only output when the estimated warp is nonlinear (and hence a whole dataset is needed to describe local shifts/warps), which would be estimated by 3dQwarp, @SSwarper, @animal_warper, etc. The main output in terms of alignment parameters is the set of affine parameters: (by default) 12 numbers that represent shifts, rotations, shears and scalings of a dataset. Affine parameters are global, hence apply to stretch or rotate the whole dataset, and so only the 12 numbers are needed in either "matrix" or "parameter" form---hence it would be good to know what command you actually ran, for getting this registration information out.

The dataset output by is most likely the one showing the source dataset aligned/registered to the base one, hence I guess it is a 3D volume only to be overlayed on the reference/base one. (Note: a nonlinear warp dataset would typically have three subvolumes, each representing a local shift along a different dimension.)