In Situ Change Analysis and Monitoring through Terrestrial Laser Scanning

In addition to inherent degradation with time, geologic hazards such as coastal erosion, landslides, and seismic activity constantly threaten public infrastructure. Repeat surveys using terrestrial laser scanning [TLS, ground-based light detection and ranging (LIDAR)] enable rapid, time-series, three-dimensional (3D) data acquisition to map, see, analyze, and understand the influence of such processes. Previously, change detection and analysis between scan surveys has been conducted during postprocessing upon return to the office, limiting the effectiveness and efficiency of the field investigation. A newly developed methodology quickly georeferences scans upon field acquisition and immediately performs change detection using a novel algorithm to compare acquired scans to baseline models directly in the field. Implementation and testing of the change analysis algorithm was performed on objects moved in a laboratory setting, on displaced piles at an outdoor geotechnical testing facility, and on site at an active landslide. The developed methodology and algorithm successfully detected and quantified varying degrees of change and showed significant time savings compared to traditional postprocessing techniques and common change analysis approaches.