Ultrasound scattering model: 2-D cross-correlation and focusing criteria--theory, simulations, and experiments.

A microscopic scattering model is developed to expedite simulation studies of ultrasound imaging in soft tissue using multichannel transducer probes. The model fully accounts for the physics of broadband signals, propagating wave packets, and time delay focusing. Analytical results are presented for 2-D transducer arrays; 1-D results can be trivially extracted by setting the number of rows equal to unity. The 2-D cross-correlation and the 2-D form of the Mallart-Fink (MF) focusing factor are calculated. It is demonstrated that the scattering model reduces to the 2-D form of the monochromatic van Cittert Zernike (VCZ) analysis. Simulation results for the focusing factor are presented, and comparisons are given between the values obtained from simulation, analytical theory, and actual water tank experiments. The comparative results are all in close accord with each other.