Permanent Laser Scanning and 3D Time Series Analysis for Geomorphic Monitoring using Low-Cost Sensors and Open-Source Software

Abstract. This study presents a first assessment of the performances of a low-cost permanent laser scanning (PLS) system for geomorphic monitoring applications. The goal is to evaluate the applicability and accuracy of these accessible technologies in comparison with high-end, commercial laser scanning systems. The assessment focuses on accuracy estimations and reliability in detecting and quantifying geomorphic changes over time in a target area in the Rotmoos valley, located in the Ötztal (Tyrol, Austria), featuring sediment movement and riverbed changes that are manually induced in an experimental setup. In this study, we use a Livox Avia scanner, controllable via an open SDK and Raspberry Pi, as low-cost monitoring setup in comparison to a high-end RIEGL VZ-2000i TLS. We acquired 14 epochs of point clouds from both systems simultaneously while inducing changes to the scene in-between acquisitions. Changes are quantified via direct point cloud comparison using the M3C2 algorithm and assessed both spatially per epoch as well as regarding the time series information at selected locations. Our results show consistent change values and patterns obtained with both Livox and RIEGL scans, demonstrating that, despite minor differences in time series trends, the low-cost Livox scanner effectively captures geomorphic changes comparable to those measured by the RIEGL. Our presented approach, by leveraging affordable hardware and open-source software tools, could provide a cost-effective solution for long-term environmental monitoring. By comparing the results obtained from both systems, this research highlights the potential of low-cost alternatives for continuous geomorphic monitoring, offering valuable insights for cost-effective environmental management and research.