Map fixed and moving images to their half-way space

[devDonnn]

I use the following command to register two T1w images:

antsRegistrationSyNQuick.sh -d 3 -f vol1.nii.gz -m vol2.nii.gz -o output_ -t so -n 4 -j 1

Now, for my particular application I want to apply warps for both images - fixed and moving - so these end up being co-registered as well. I see that I get both images warped but either image1 is mapped to image2 space or image2 mapped to image1 space. Instead, I would like to apply (half?) warps on both so both undergo warps (AND interpolation) and are well-registered too (same space). Is this possible? This is analogous to FreeSurfer's mri_robust_register tool where both images are co-registered to their half-way space.

[ntustison]

unbiased_pairwise_registration.sh