Workbench Command is a set of command-line tools that can be used to perform simple and complex operations within Connectome Workbench.
REGRESS AFFINE FROM WARPFIELD
wb_command -volume-warpfield-affine-regression
<warpfield> - the input warpfield
<affine-out> - output - the output affine file
[-roi] - only consider voxels within a mask (e.g., a brain mask)
<roi-vol> - the mask volume
[-fnirt] - input is a fnirt warpfield
<source-volume> - the source volume used when generating the fnirt
warpfield
[-flirt-out] - write output as a flirt matrix rather than a world
coordinate transform
<source-volume> - the volume you want to apply the transform to
<target-volume> - the target space you want the transformed volume to
match
For all voxels in the warpfield, do a regression that predicts the
post-warp coordinate from the source coordinate. When -roi is specified,
only consider voxels with a value greater than 0 in <roi-vol>.
The default is to expect the warpfield to be in relative world
coordinates (mm space), and to write the output as a world affine (mm
space to mm space). If you are using FSL-created files and utilities,
specify -fnirt and -flirt as needed, as their coordinate conventions are
different.