Information extraction: from electromagnetic response to ground characteristics

Person in charge: J.-M. Nicolas, LTCI - Télécom ParisTech

The objectives of this first subproject concern the extraction of relevant information for the monitoring of natural environment deformation and subsidence. Natural environments are generally characterized by a strong variability of their scattering behavior in both space and time, which may severely affect the accuracy of displacement estimation techniques. Such effects are mainly due to the scene topography (amplitude and phase modifications, SAR reconstruction errors, geometric distortions, shadowing,...) and to the intrinsic nature of the observed natural media. In the framework of displacement estimation, two kinds of natural media can be discriminated:

• Coherent scatterers (CS) are characterized by a stable response which may be detected and recognized at different acquisition dates.
• Distributed media (surfaces, volumes) have a response dominated by speckle. Geometrical variations (displacements or change in the surface or volume structure) may then be estimated using incoherent techniques, like amplitude correlation, or partially coherent ones from interferometric image pairs.

It is why we propose to develop specific tools devoted to coherent scatterers (Work Package 1) and to media characterization (Work Package 2). These tools will be used by the second subproject to guide the extraction of displacement measure and the third subproject to assess the confidence in the results.