Fringe detection in SAR interferograms

In last decades many interferometric Synthetic Aperture Radar (SAR) applications have been developed aiming at measuring terrain morphology or deformations. The geodesic information is carried by the interferometric phase. However, this can be observed only in the principal interval giving the so called wrapped phase. To extract the interesting information, e.g., height surface or terrain deformation, the absolute phase should be estimated from the wrapped phase observations. In this work we present an approach to solve PU relying on the local analysis of the wrapped phase signal gradients to recover fringes and phase jumps. The proposed fringe detection algorithm is tested on both synthetic and real data. Synthetic phase surfaces are generated characterized by different signal-to-noise ratio and using a real topographic scene. Real interferograms obtained by processing ENVISAT and TerraSAR-X SAR images are also used to test the above algorithm. First results show that the proposed approach is able to recognize and reconstruct fringes in noisy interferograms.