Extraction of Bridge Features from high-resolution InSAR Data and optical Images

Modern airborne SAR sensor systems provide geometric resolution in the order well below half a meter. By SAR interferometry from pairs of such images DEM of the same grid size can be obtained. In data of this kind many features of urban objects become visible, which were beyond the scope of radar remote sensing only a few years ago. However, because of the side-looking SAR sensor principle, layover and occlusion issues inevitably arise in undulated terrain or urban areas. Therefore, SAR data are difficult to interpret even for senior human interpreters. Furthermore, the quality of the InSAR DEM may vary significantly depending on the local topography. In order to support interpretation SAR data are often analyzed using additional complementary information provided by maps or other remote sensing imagery. In this paper a fusion of high-resolution InSAR data and one aerial image is discussed for the example of a scene containing bridges that are core elements of infrastructure. The aims are improvement of the 3D visualization of the scene and the extraction of the main parameters of the bridges´ geometry.