Extraction of Bridges over Water in Multi-aspect High-resolution Insar Data

Modern airborne SAR sensors provide spatial resolution in the order well below half a meter. In such data many features of urban objects are visible, which were beyond the scope of radar remote sensing only a few years ago. Core elements of urban infrastructure are bridges. In high-resolution InSAR data even small bridges are mapped to extended data regions covering large numbers of pixels. Therefore, in data of this quality the identification of bridge structure details is possible at least by visual interpretation. The special appearance of bridges over water in high-resolution InSAR data is discussed. Geometric constraints for the mapping of certain bridge elements in interferometric SAR imagery are given. An approach for detection of such bridges is proposed. Information about the bridge structure is extracted in subsequent fine analysis. First results of the approach are demonstrated using orthogonal InSAR single-pass data sets of spatial resolution better than 40cm.