Semi-Global Matching of Pléiades Tri-Stereo Imagery to Generate Detailed Digital Topography for High-Alpine Regions

Abstract

Nowadays, several sensors are capable of acquiring very high resolution (VHR) satellite images in stereo, and even in tri-stereo mode. These data can be efficiently exploited with photogrammetric methods, such as semi-global matching (SGM), to produce high quality 2.5D digital terrain information. Regarding the production of digital terrain models, since VHR (tri-)stereo satellite images are available at high temporal frequencies for nearly the whole globe, they can be considered an attractive alternative to restricted and expensive airborne laserscanning (ALS) data. In this study, SGM is applied to a Pléiades-1A image triplet, to generate an accurate and detailed 3D point cloud and a 2.5D digital surface model (DSM) for a high-alpine study area in South Tyrol with complex, snow- and ice-covered topography. Visual and quantitative comparison to an ALS reference DSM showed that there were only small elevation errors for large parts of the study area. Errors were higher in regions that were obscured by shade. This is one of the first studies demonstrating that SGM is not only capable of delivering reliable digital surface information for flat and hilly regions, but also for high-alpine areas with complex terrain.