I tried registering two hi-res, high contrast images (SPGR 256x256x124, skull-stripped) from
the same individual acquired a few months apart. When I used 7 dof, the registration was
perfect. However, when I used 12 dof, the registration was off by about 90 degrees and badly
scaled (around a factor of 1.5). The results were the same for correlation ratio and mutual
info. I checked the headers, and the voxel sizes were identical and correct. Any idea why this
Do you think that applying a bias field correction to example_func would improve the
registration to the hi-res structural image?