afni.nimh.nih.gov

Hi Michael,

That program uses weighted least squares over
the volume as a cost function. So all voxels matter,
though low intensity ones are almost irrelevant.

A small shift (or any, for that matter) just means
resampling the volume on a transformed grid and
computing a new cost. If the cost happens to be
lower after applying a 0.005mm shift, so be it.

- rick