xfmdecomp
decompose a .xfm transformation into rotation, translation, scale, and shear
xfmdecomp <input.xfm>
DESCRIPTION
xfmdecomp is a Perl script that decomposes a linear MNI .xfm transformation file into its constituent geometric components: rotation angles, scale factors, shear parameters, and translation offsets. The decomposed parameters are printed to standard output.
This is useful for inspecting registration results, verifying that transformations are within expected ranges, and extracting specific geometric parameters for analysis or reporting.
The decomposition extracts:
- Rotations: angles around the x, y, and z axes (in degrees)
- Translations: offsets along the x, y, and z axes (in millimetres)
- Scales: scaling factors along the x, y, and z axes
- Shears: shear parameters
Only linear (affine) transformations can be decomposed. Non-linear grid transformations are not supported.
OPTIONS
xfmdecomp does not accept option flags. The single argument is the transform file to decompose.
<input.xfm>- Input MNI transformation file containing a linear (affine) transform.
EXAMPLES
Decompose a linear transformation:
xfmdecomp registration.xfm
Save the decomposition to a file:
xfmdecomp registration.xfm > params.txt
AUTHOR
Andrew Janke - McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University.
COPYRIGHTS
Copyright © 2000 by Andrew Janke