Evaluation of Reflectance for Building Materials Classification With Terrestrial Laser Scanner Radiation

Abstract

The main purpose of this work is the evaluation of the potential of Terrestrial Laser Scanning (TLS) technology to perform a reflectance analysis of scanned objects. A laser beam, having a coherent beam in the field of visible light (wavelength between 532nm and 680 nm), can lead to optical diffraction phenomena that allow a correlation between the degree of crystallinity of solids (in particular dispersed crystalline materials) and its reflectivity. Different materials with known crystallinity values have been examined and the diffraction value has been analysed for two types of lasers, one pulsed and the other phase measurement, with two different acquisition conditions (nadiral and oblique position). The results demonstrated the correlation by verifying that the incident laser light beam is more refracted by materials with a higher degree of crystallinity than less crystalline or amorphous materials.

Smartphone LiDAR Technologies for Surveying and Reality Modelling in Urban Scenarios: Evaluation Methods, Performance and Challenges

“…The 1 cm resolution scan of brass was good, while the 1.5 cm and 2 cm resolution scans produced surface variation values of 0.1455 and 0.1000 due to some splitting and deformation (Figure 15b,c). Problems in scanning metallic materials could be caused by the surface structure; metallic materials can be scanned more easily by increasing the acquisition distance and angle of the laser beam [15].…”

“…In this test, we considered albedo as a parameter characterising the material. The measurement of albedo was documented in [15]. We performed the scans by keeping the mobile devices in the nadir direction to the samples and moving them as little as possible (near-static conditions).…”