Using terrestrial laser scanner and RPA-based-photogrammetry for surface analysis of a landslide: a comparison

Abstract: Gravitational mass movements are natural destructive processes that can cause enormous losses. New technologies such as laser scanning and remotely piloted aircrafts (RPA) along with Structure-from-Motion-Multi-View Stereo (SfM-MVS) photogrammetry technique provides an alternative to conventional mapping methods. A hill with a landslide located in the city of Cunha - SP was surveyed by terrestrial laser scanner (TLS) and RPA-based SfM-MVS. SfM-MVS point cloud covers a larger area and point distribution is more homogeneous while TLS points have an uneven distribution. Small distances between point clouds were predominant in the vicinity of the landslide and greater differences only occurred on the scene edges. DEMs (Digital Elevation Model) were generated from both point clouds. The volume of material displaced from the upper part (scarp) of the landslide was 70.05 m3 for the TLS DEM and 77.15 m3 for the SfM-MVS while the volume of material accumulated in the lower part (body) of the landslide was 66.85 m3 and 62.68 m3 respectively. Slope and roughness were calculated and showed very similar results for TLS and SfM-MVS.

摘要：重力块体运动是一类可造成巨额损失的自然破坏性过程。激光扫描、遥控航空器（RPA）以及运动恢复结构-多视图立体匹配（SfM-MVS）摄影测量技术等新兴技术，为常规测绘方法提供了替代方案。研究针对圣保罗州库尼亚市一处发育滑坡的山丘，采用地面激光扫描仪（TLS）与基于RPA的SfM-MVS技术开展测绘。结果显示，SfM-MVS点云覆盖范围更广、点分布更均匀，而TLS点云的点分布则相对不均；滑坡周边区域的点云间距普遍较小，仅在场景边缘处存在较大差值。研究分别基于两类点云生成了数字高程模型（DEM）。滑坡上部（陡坎）的物质位移体积，TLS生成的DEM计算结果为70.05 m³，SfM-MVS的结果为77.15 m³；滑坡下部（滑体）的物质堆积体积则分别为66.85 m³与62.68 m³。此外，研究还计算了坡度与粗糙度指标，两类方法的计算结果高度相似。