High Resolution SAR Interferometry: influence of local topography in the context of glacier monitoring
Résumé
SAR interferometric data offers the opportunity to measure temperate glacier surface topography and displacement between the two acquisitions. Recently, reliable estimates of the phase gradient given by interferogram local frequencies become mandatory with the increase of the SAR resolution. In this paper, an original 2-step method for estimating local frequencies is proposed. The 2D phase signal is considered to have two deterministic components corresponding to low-resolution fringes and high-resolution patterns due for instance to the micro-relief. The first step of the proposed algorithm consists in the low-resolution phase flattening. In the second step the local high-resolution frequencies are estimated from the phase auto-correlation functions computed on adaptive neighborhoods using only the pixels which belong to the same HR spatial feature and respect the ”local stationarity” hypothesis. Results with both real ERS 1/2 tandem and simulated TerraSAR-X interferograms are presented to illustrate the potential of the proposed method.