A method to increase the image formation speed in an annular-array digital ultrasound system consisting of N elements with a plurality of transmit and receive channels. Selectively dropping one or more transmit or receive channels during image formation reduces the amount of data needed to form an image, thus increasing the image formation frame rate through faster scan speeds or reducing the amount of digitized data required to process an image. The improved frame rate does result in some reduction in resolution, SNR and potentially DOF, but these drawbacks can be mitigated by synthetically recovering missing transmit-to-receive data pairs.
