1Statistical Stability of Ultrawideband Time-Reversal Imaging in Random Media

Abstract—We carry out a study on the statistical stability of ultrawideband (UWB) time-reversal (TR) imaging in random me-dia under different combinations of random medium parameters and interrogating signal properties. We examine conditions under which frequency decorrelation in random media provides a more effective “self-averaging ” and therefore better statistical stability. We also present a new frequency-synthesized technique for UWB time-reversal-based imaging. This technique is employed to construct time-reversal-operator-decomposition (DORT under its French acronym) and multiple-signal-classification (MUSIC) images using either linear or full-aspect transceiver array config-urations. The proposed technique automatically provides the best images of desired target(s) in terms of focusing resolution without the need for (synthetic) propagation of time-reversed signals and ad hoc determination of the optimal focusing time instant. In addition, information about the imaging domain (background) can be stored and reused to reconstruct different targets. Index Terms—Frequency decorrelation, MUltiple SIgnals Clas-sification (MUSIC), statistical stability, time-reversal, volumetric beamforming. I