Surgical vs. algorithm alignment. Simulated alignments of the HMMS to CANAL based on random initial misalignments (N = 10,000). Two techniques were compared: surgical alignment (blue) of the HMMS-HEAD or algorithm alignment (green) of the HMMS-HEAD via the BBS. (a) Probability density function of RMS error shows lower mean error for algorithm (0.58°/s) compared to surgical (2.29°/s) alignment. (b) Probability density function of point-to-point error also shows lower mean error for algorithm (2.21%) compared to surgical (11.04%) alignment.