Table 1.

Summary of the main features of the tracking system, as were obtained using home‐made phantoms

precision for relative motion	$<0.3 \text{mm}$
precision in absolute position for big displacements (20 cm)	$<1 \text{mm}$
maximum speed detected	11.5 cm/s
minimum amplitude of periodic motion detection	$<0.4 \text{mm}$
precision when tracking Anzai phantom	${\mathrm{R}}^2>0.996$
number of independent points tracked	arbitrary a

^aOnly limited by the speed of the computer; up to 20 in the proposed setup.