Height Retrieval of Isolated Buildings from Single High Resolution SAR Images

Detection of man-made structures in urban areas, in terms of both geometric and electromagnetic features, from a single, possibly High Resolution (HR), Synthetic Aperture Radar (SAR) image is a highly interesting open challenge. Within this framework a possible approach for the extraction of some relevant parameters, describing shape and materials of a generic building, is here proposed. The approach is based on sound electromagnetic models for the radar returns of each element of the urban scene: a fully analytical representation of electromagnetic returns from the scene constituents to an active microwave sensor is employed. Some possible applications of feature extractions from real SAR images, based on above approach, have been already presented in literature as first examples of potentiality of a model-based approach but here the overall theory is analyzed and discussed in depth, to move to general considerations about its soundness and applicability, as well as efficiency of further applications may be derived. For the sake of conciseness, although the proposed approach is general and can be applied for the retrieval of different scene parameters (in principle, anyone contributing to the radar return), we here focus on the extraction of the building height, and we assume that the other parameters are either a priori known (e.g., electromagnetic properties of the materials), or have been previously retrieved from the same SAR image (e.g., building length and width). An analysis of the sensitiveness of the height retrieval to both model inaccuracies and to errors on the knowledge of the other parameters is performed. Some simulation examples accompany and validate the solution scheme that we propose.