Table 2. Population averages and maximum values for different quantities introduced in Equations 1, 4 and 5 to measure the uncertainties introduced by a reduced number of imaging sessions.

Direction	δ(4) (mm)	Max δ(4) (mm)	R(4) (mm)	Max R(4) (mm)	Δ(4) (mm)	Max δ(4) (mm)
x	0.89±0.93	3.15	2.05±1.34	6.62	0.85±0.82	2.15
y	0.65±0.47	1.83	1.63±0.44	2.77	0.65±0.484	2.09
z	1.12±0.86	3.87	2.11±0.78	4.37	0.83±0.61	2.44