Rock wall characterization using high-speed vehicle-mounted videogrammetry

Rock wall characterization is important for the safety and maintenance of transportation and mining operations. In Nordic countries, extensive rock slope inspections are regularly required to ensure operational safety, but the traditional manual methods are both time-consuming and hazardous for the inspectors. This research explores the use of vehicle-mounted videogrammetry as an alternative to traditional manual or drone-based photogrammetry for rock wall inspections. Videogrammetry involves extracting consecutive frames from video footage captured by a moving vehicle. The method was tested for its accuracy in generating 3D models of rock slopes and its suitability for kinematic rockfall hazard assessments. The results indicate the method produces spatially accurate models with minimal deviations from drone-based photogrammetry, providing reliable data for rockfall simulations. Rockfall hazard metrics such as Probability of Failure (PoF) and Factor of Safety (FoS) were consistent with those from drone-based models. Additionally, the data acquisition was much faster, making it an ideal solution for routine inspections of long road segments or large mining sites. Compared to airborne laser scanning (ALS), the proposed method offers better rock wall surface detail, ensuring more precise rockfall hazard predictions. This study demonstrates that vehicle-mounted videogrammetry is a practical and efficient tool for regular rock slope inspections in both transportation and mining sectors.