DSM generation from very high optical and radar sensors: Problems and potentialities along the road from the 3D geometric modeling to the Surface Model

The availability of new high resolution optical and radar spaceborne sensors offers new interesting potentialities for the acquisition of data useful for the generation of Digital Surface Models (DSMs). The accuracy level of DSM is strictly related both to the image orientation and to the matching process. As regards the image orientation, remote sensing community usually adopts two different types of models for High Resolution Satellite Imagery (HRSI): the physical sensor models and the generalized sensor models also called rigorous and Rational Polynomial Functions (RPFs) models respectively. In a scientific software developed by the research group of Geodesy and Geomatic Area of the University of Rome "La Sapienza" both rigorous and RPFs models are implemented, with a specific tool for the terrain-independent Rational Polynomial Coefficients (RPCs) generation; the software manages the imagery acquired by several optical sensors (EROS A, Ikonos, QuickBird, Cartosat-1, WorldView-1, GeoEye-1) and by the Italian SAR constellation COSMO-SkyMed. In the same software a facility for image matching is embedded. The Area Base Matching (ABM) is used, combined with the orientation model re-parametrized in terms of RPCs. In the present work some examples of models application and DSM generation are analyzed and discussed.