Table 2.

The distance error of the robotic arm (unit: mm).

Number of point	Coordinates of the target point			Number of image	Coordinates of the guided pinpoint			Distance error
	x	y	z		x	y	z
Case A: 3 cm
1	26.7	8.9	−46.5	I	27.0	8.2	−46.6	0.78
				II	27.4	8.1	−46.5	1.06
				III	26.5	8.4	−46.7	0.57
2	6.2	−5.4	−45.2	I	6.1	−5.3	−44.9	0.33
				II	6.3	−5.2	−44.6	0.64
				III	5.3	−4.6	−45.1	1.20
3	1.8	−19.1	−61.5	I	1.9	−19.3	−62.1	0.64
				II	1.9	−19.6	−62.1	0.78
				III	1.7	−19.5	−61.8	0.50
Max error: 1.20; average error: 0.72; standard deviation: 0.26
Case B: 7 cm
1	38.9	27.9	−89.6	I	39.2	27.8	−90.5	0.95
				II	39.2	27.9	−90.6	1.04
				III	39.6	27.8	−90.4	1.06
2	18.3	14.0	−87.7	I	18.1	13.5	−88.2	0.73
				II	17.5	13.7	−88.5	1.17
				III	18.2	13.8	−88.1	0.45
3	13.7	−0.1	−104.5	I	14.0	−0.6	−105.5	1.15
				II	14.2	−0.4	−105.6	1.24
				III	14.1	−0.1	−105.8	1.36
Max error: 1.36; average error: 1.02; standard deviation: 0.26
Case C: 12 cm
1	54.1	46.8	−136.3	I	55.4	46.6	−136.1	1.33
				II	53.5	47.4	−137.6	1.55
				III	53.9	47.2	−137.4	1.19
2	33.2	32.9	−134.6	I	34.5	32.7	−134.2	1.37
				II	32.6	33.4	−135.3	1.05
				III	32.8	33.6	−135.3	1.07
3	28.9	19.0	−151.6	I	29.8	19.4	−151.3	1.03
				II	28.0	20.1	−152.1	1.51
				III	28.0	19.3	−153.0	1.69
Max error: 1.69; average error: 1.31; standard deviation: 0.23