Table 3.

Mean and standard deviation of rotational angle errors in simulation studies -- I. without noise in the 2D marker positions and II. with different levels of errors in 2D marker positions, and in phantom experiments.

Cases	Motion Type		Mean ± std. (°) of rotational angle errors
			LR (pitch)	AP (yaw)	SI (roll)
Simulation I	TM, RM, TRM		< 10−3
Simulation II	TRM with 2D noise level (mm) ([μ, σ])	[0, 0.22]	0.7 ± 0.4	0.5 ± 0.4	0.6 ± 0.4
		[0, 0.44]	1.1 ± 0.9	1.1 ± 0.7	1.1 ± 0.6
		[0, 0.388]	1.1 ± 0.7	1.2 ± 0.7	0.9 ± 0.7
		[0, 0.776]	2.5 ± 1.9	1.9 ± 1.2	1.9 ± 1.4
Phantom experiment	TM		0.1 ± 0.2	−0.6 ± 0.3	−0.8 ± 0.4
	RM	AP	0.1 ± 0.3	1.5 ± 0.6	0.6 ± 0.7
		SI	0.5 ± 0.2	0.5 ± 0.4	1.7 ± 1.0
	TRM	SI	−0.1 ± 0.2	−1.1 ± 0.7	0.4 ± 1.0