Beam-based time reversal imaging

We present a beam-based time reversal (TR) imaging scheme for point scatterers, utilizing data measured by arrays of wide-angle sources and receivers. The scheme starts with a pre-processing phase where the sources/receivers arrays are divided into sub-arrays, and the field of each sub-array is transformed using a discrete Fourier transform (DFT) into a set of directional beams. This converts the wide-angle transducers data into the beam-domain data, describing the amplitudes of the scattered beams due to each excitation beam. The beam-domain time-reversal processing phase is formulated next. It is shown that the beam-domain TR operator is sparse and low rank for a given sub-domain of interest in the target domain.