3D displacement retrieval on glacial areas by airborne multi-view photogrammetry

Résumé — With the development of photogrammetry and computer vision, Unmanned Aerial Vehicle (UAV) embedded with digital compact camera plays an important role on gathering geographic information [1]. In this context, a novel method is proposed in this article for monitoring displacement of natural environment by airborne multi-view photogrammetry. The method is implemented for calculating 3D displacement of a glacier area in one month and a half. We illustrate the application of Micmac, a powerful and free photogrammetry software, for point cloud reconstruction. With the GPS embedded on the UAV whose precision is not quiet high, we succeed in georeferencing point clouds. As we do not have any ground control point in land, two different ways of registration have been introduced to align point clouds. Afterwards, a set of tools is presented for calculating 2D displacement maps from point clouds. We introduce at last an inversion processing to calculate a 3D displacement map. The final result shows the 3D displacement of each pixel in the entire scene. Since final result is influenced by the precision of point cloud registration, this paper also highlights useful improvements to do in the future to obtain the 3D displacement with higher precision.