EFIDIR: extraction and fusion of information for displacement measurement from radar imagery
Spaceborne SAR (Synthetic Aperture Radar) imagery allows ground displacement to be measured with a precision as high as centimer or even millimeter by using series of images. This precision can be reached only by exploiting the mass of radar available data or the potential of recently launched satellites: high-resolution (Metric) or polarimetric images. This article presents the main results obtained by the ANR project EFIDIR (Extraction and Fusion of Information for Displacement measurement from Radar imagery, 2008-2012) which gathers specialists of SAR images, information processing and geosciences. A ground based SAR (GB-SAR) and specific processing methods were developed (radar tomography. oversampling of complex images...) to improve the characterization of electromagnetic scattering and EAR data pre-processing. The methods for extracting displacement information from the amplitude (texture tracking) or from the phase (multitemporal interferometry) have been expanded and tested on glacier large displacements or small interseismic deformations. An original data mining approach has also been developed for extracting frequent sequential patterns and successfully applied to the detection of patterns related to the ground deformation hidden by atmospheric artifacts. Finally a new approach to represent uncertainty by the possibility theory was introduced in the inversion step that can reconstruct 3D displacement fields (East, North, Up) or estimate the model parameters of geophysical phenomena at the origin of the observed surface displacements. These studies thus illustrate the major stages of processing chains from SAR data acquisition to geophysical modeling.
sar images interferometry data mining geophysics polarimetry