Aperture analysis of coarrays for focused ultrasound imaging

A coarray in an ultrasound imaging system consists of a pair of transmit and receive arrays that can generate identical point spread functions. As an imaging system with two-dimensional arrays is required to mitigate receiver complexities, the coarray can be an effective concept to select the minimum number of arrays with the same performances as the full array. Both analytical evaluations and simulations confirm that the coarray is affected by the angle of the selected imaging plane, but is achievable when the images are reconstructed by using the dynamic transmit focusing method with overlapping wave fields from transmit beams.