Single-channel time reversal with Lanczos iterations.

Abstract

Recent investigations of array-based time reversal techniques employing Lanczos iterations have demonstrated convergence properties superior to equivalent methods using power iterations [A. A. Oberai et al., “Efficient time reversal by Lanczos iterations,” J. Acoust. Soc. Am. 123, 3596 (2009)]. In numerical scattering simulations, time reversal techniques developed for a single-channel transducer are applied to study echoes from a thin-walled spherical shell. When power iterations are employed, a narrowband waveform corresponding to the dominant scattering mode of the target is selected. Lanczos iterations converge to this waveform in fewer transmissions and simultaneously identify additional higher-order target scattering features. The performance of both techniques is studied in the presence of varying levels of stochastic and deterministic noise. [Work supported by the Office of Naval Research.]