Table 6. Effect of materials on range measurements.

Material	Scanner	Mean Value	Standard Deviation	Relative Error	RMSE
		${\stackrel{-}{\mathit{x}}}_{\mathit{M}}$(mm)	${\stackrel{-}{\mathit{\sigma }}}_{\mathit{M}}$ (mm)	${\stackrel{-}{\mathit{\eta }}}_{\mathit{M}}$ (%)	(mm)
Wood (True value: 4m)	URG-04LX	3985.3	17.6	-0.38	16.1
	RPLidar A1	4020.3	22.4	0.44	21.6
	UTM-30LX	4005.6	13.2	0.13	5.8
Steel (True value: 1.95m)	URG-04LX	1932.6	9.8	-0.12	19.4
	RPLidar A1	1929.0	12.4	-0.15	22.45
	UTM-30LX	1942.3	8.6	-0.09	8.7
Plastic (True value: 1.85m)	URG-04LX	1798.7	13.6	-3.2	52.3
	RPLidar A1	1789.8	16.7	-4.4	61.9
	UTM-30LX	1810.9	9.6	-2.2	39.1
Wall (True value: 3.4m)	URG-04LX	3387.3	17.8	-0.54	13.2
	RPLidar A1	3374.1	21.6	-0.63	25.5
	UTM-30LX	3393.7	11.8	-0.51	6.7