Sparse geometries for two-dimensional array transducers in volumetric imaging

Two random sparse array geometries and an ad hoc sparse array were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth of field comparisons were made from simulated on-axis beamplots for both normal and parallel processing receive beams. A random array with Gaussian distribution of transmitters and uniform distribution of receivers was found to have better resolution and depth of field than the other sparse arrays. This array was fabricated and experimental system response measurements were made. Comparisons of B-scan images of a tissue mimicking phantom show improvement in resolution and depth of field that is consistent with simulation results