Close-Range Photogrammetric Techniques for Deformation Measurement: Applications to Landslides

In this chapter, the application of close-range photogrammetry for deformation measurements in the field of landslide investigation and monitoring is discussed. Main advantages of this approach are the non-contact operational capability, the large covered area on the slope to analyze, the high degree of automation, the high acquisition rate, the chance to derive information on the whole surface, not limited to a few control points (area-based deformation measurement), and, generally, a lower cost with respect to 3D scanning technology. Applications are organized into two categories: (1) surface-point tracking (SPT) and (2) comparison of surfaces obtained from dense image matching. Different camera configurations and geometric models to transform points from the image space to the object space are also discussed. In the last part of the chapter, a review of the applications reported in the literature and two case studies from the experience of the authors are reported.