How to Efficiently Determine the Range Precision of 3D Terrestrial Laser Scanners

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 6; p. 1466
• Main Authors: Schmitz, Berit, Holst, Christoph, Medic, Tomislav, Lichti, Derek D, Kuhlmann, Heiner
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26-03-2019; MDPI
• Subjects: Accuracy; Cyclones; Deformation; Deformation analysis; Geodetics; intensity; Laser beams; Lasers; Measurement techniques; Range finders; range precision; Scanners; Software; stochastic model; Stochastic models; Surface geometry; Surveying; terrestrial laser scanning; Switzerland; Germany; intensity; terrestrial laser scanning; range precision; stochastic model
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19061466

As laser scanning technology has improved a lot in recent years, terrestrial laser scanners (TLS) have become popular devices for surveying tasks with high accuracy demands, such as deformation analyses. For this reason, finding a stochastic model for TLS measurements is very important in order to get statistically reliable results. The measurement accuracy of laser scanners-especially of their rangefinders-is strongly dependent on the scanning conditions, such as the scan configuration, the object surface geometry and the object reflectivity. This study demonstrates a way to determine the intensity-dependent range precision of 3D points for terrestrial laser scanners that measure in 3D mode by using range residuals in laser beam direction of a best plane fit. This method does not require special targets or surfaces aligned perpendicular to the scanner, which allows a much quicker and easier determination of the stochastic properties of the rangefinder. Furthermore, the different intensity types-raw and scaled-intensities are investigated since some manufacturers only provide scaled intensities. It is demonstrated that the intensity function can be derived from raw intensity values as written in literature, and likewise-in a restricted measurement volume-from scaled intensity values if the raw intensities are not available.