Terrestrial laser scanner to detect landslide displacement fields: a new approach.

A terrestrial laser scanner (TLS) allows the generation of a detailed model of a landslide surface. In this way, when two or more georeferenced models obtained by multi‐temporal scans are available, the landslide displacement field can be computed. Nevertheless, such a computation is a relatively complex task because the recognition of correspondences among the multi‐temporal models is required. The Iterative Closest Point (ICP) algorithm allows the alignment of two 3D objects having a common part by iterative shape matching. A new method for the automatic calculation of a landslide displacement field is presented here. It is based on a piecewise application of the ICP algorithm and is made possible by the robustness of this algorithm against noise and small morphological modifications. After a series of numerical experimentations, this method was successfully applied to two test sites located in the North‐Eastern Italian Alps affected by high‐risk landslides of the slump type (Perarolo di Cadore and Lamosano) with very different observational conditions.