Results

The study of figure uses synthetic data. The physical surface S is generated from the MRI scalp, then submitted to a known geometric transformation. Using this method, we know the exact transformation that the algorithm should find, which allows us to evaluate its accuracy.

  

Figure 7.4: MRI to physical space registration. Left: unregistered Right: registered.

A typical registration result is illustrated at figure . We applied a variety of rigid transformations to the synthetic data, including translations up to 5 cm and rotations from -20^o to +20^o around each axis. In all cases, the registration procedure recovers the exact inverse transformation with sub-pixel accuracy.
Practically, for non-synthetic data, the accuracy of the registration is limited by the MR image voxel size and the discrete nature of the scalp surface.