Time-reversal algorithms in viscoelastic media

Imaging and time reversal in random media

We present a general method for estimating the location of small, well-separated scatterers in a randomly inhomogeneous environment using an active sensor array. The main features of this method are (i) an arrival time analysis of the echo received from the scatterers, (ii) a singular value decomposition of the array response matrix in the frequency domain, and (iii) the construction of an obje...

Time Reversal for Waves in Random Media

In time reversal acoustics experiments, a signal is emitted from a localized source, recorded at an array of receivers-transducers, time reversed, and finally re-emitted into the medium. A celebrated feature of time reversal experiments is that the refocusing of the re-emitted signals at the location of the initial source is improved when the medium is heterogeneous. Contrary to intuition, mult...

Time reversal for waves in time-dependent random media

s : Regularization through stochastic forcing and its impact on nonlinear time-reversal A. Nachbin IMPA, Est. D. Castorina, 110, J. Botanico, CEP 22460-320, Rio, RJ, Brasil A large amount of mathematical theory has been developed for the time-reversal of linear waves in random media. This work concerns the extension to one-dimensional, weakly nonlinear water waves. Weakly dispersive water waves...

Time Reversal for Classi al Waves in Random Media

Interferometric Imaging and Time Reversal in Random Media

Short Description. We present a comparative study of time reversal and array imaging in random media. We explain that the time reversal process is fundamentally different than imaging, and it cannot be used for imaging purposes. We also describe briefly the resolution of time reversal and imaging. Since they occur in random media, the resolution theory is augmented with the important concept of...