Table 1.

Errors are computed by measuring the average of the absolute distances between eight radiolucent landmarks implanted in the femur head, greater trochanter, patella, and the condyle. The residual distances are measured between the opposite sides of the femur (hip to knee). Errors in angular measurements for tibiofemoral (TF) and lateral‐distal femoral (LDF) are reported in the last two columns. Each method is tested twice on the animal cadaver. The C‐arm translation was nearly 210 mm to acquire each nonoverlapping CBCT volume. The first four rows present the results using vision‐based methods suggested in this paper. We then present the errors of registration using external trackers as well as image‐based stitching of overlapping CBCT volumes with NCC similarity measure. Note that in this table the results of stitching using 2D features (Section 5.B) are not presented as measurements on a similar animal specimen were not reported in Ref. [24]. All errors are measured by comparing the stitching measurements with the measurements from a complete CT of the porcine specimen as ground truth

Tracking method error	Stitching error (mm)	Absolute distance error (%)	TF error	LDF error
	Mean ± SD	Mean	Mean ± SD	Mean ± SD
Marker tracking of patient (Section 4.A.1)	0.33 ± 0.30	0.14	0.6° ± 0.2°	0.5 ± 0.3°
Marker tracking of surgical bed (Section 4.A.2)	0.62 ± 0.21	0.26	0.7 ± 0.3°	2.2 ± 0.4°
RGBD‐SLAM tracking (Section 4.B)	0.91 ± 0.59	0.42	0.5 ± 0.2°	0.6 ± 0.4°
Surface data tracking (Section 4.C)	1.72 ± 0.72	0.79	1.0 ± 0.7°	3.1 ± 1.9°
Infrared tracking (Section 5.A)	1.64 ± 0.87	0.73	0.3 ± 0.1°	2.4 ± 0.8°
Image‐based registration	9.27 ± 2.11	6.52	1.2 ± 0.5°	2.7 ± 1.5°