Automatic detection and reconstruction of 2D/3D building shapes from spaceborne TomoSAR point clouds

Kurzfassung

Modern spaceborne SAR sensors such as TerraSAR-X/ TanDEM-X and COSMO-SkyMed can deliver very high resolution (VHR) data beyond the inherent spatial scales of buildings. Processing this VHR data with advanced interferometric techniques such as SAR tomography (TomoSAR) allows generation of 4D point clouds; containing not only the 3D positions of the scatterer location but also estimates of seasonal/temporal deformation on the scale of centimeters or even millimeters; making them very attractive for generating dynamic city models from space. Motivated by these chances, the authors have earlier proposed approaches that demonstrated first attempts towards reconstruction of building façades from this class of data. The approaches work well when high density of façade points exist and full shape of the building could be reconstructed if data is available from multiple views e.g., from both ascending and descending orbits. However, there are cases when no or only few façade points are available. This happens usually for lower height buildings and renders detection of façade points/regions very challenging. Moreover, problems related to the visibility of façades mainly pointing towards the azimuth direction can also cause difficulties in deriving the complete structure of individual buildings. These problems motivated us to reconstruct full 2D/3D shape of buildings via exploitation of roof points. In this paper, we present a novel and complete data driven framework for automatic (parametric) reconstruction of 2D/3D building shapes (or footprints) using unstructured TomoSAR points clouds generated particularly from one viewing angle only. The proposed approach is illustrated and validated by examples using TomoSAR point clouds generated from single viewing angle TerraSAR-X high-resolution spotlight data stacks covering two different test areas with one containing simple moderate sized buildings in the city of Las Vegas, USA and the other containing relatively complex building structures in the city of Berlin, Germany.