| -h | Help, prints usage message. |
| -o | Output file name for affine transform. |
| -I | Maximum number of iterations. |
| -N | Don't weight using normals. |
| -M | Minimum distance weight, range [0.0-1.0]: Useful values are 0.25 (default) for global matching and 0.0 for local matching.. |
| -E | Tolerance in the mean registration metric value. |
| -i | Initial affine transform object. |
| -g | Use maximal gradient contours. |
| -a | Find the general affine transform. |
| -r | Find the rigid body (aka registration) transform, default. |
| -t | Find the translation only transform. |