Hi,
The shift map is in units of voxels.
FM_UD_fmap2epi.mat is the transformation between the undistorted (UD) fieldmap (FM) and the EPI (functional/diffusion) image. As we do not assume that they are perfectly registered beforehand.
All the best,
Mark
On 10 Jul 2013, at 15:32, Mingbo Cai <[log in to unmask]> wrote:
> Hi Mark,
> Sorry it was my first time to post question here and I might have made a mistake.
> I am using the neurodebian distribution of fsl v5, installed on Ubuntu. The shift file of field map unwarping is saved in reg/unwarp/FM_UD_fmap2epi_shift.nii.gz. This is what I want because what I am trying to do is align functional data from multiple sessions to the same structure without super-sampling (I am trying to bring this file to AFNI as I am more familiar with AFNI operation). So my first question is, what is the unit of this file? Is it number of voxel, or millimeter?
> The second question is what does FM_UD_fmap2epi.mat do?
> Thanks!
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