| 摘要 |
A thinned (greater than â wavelength element spacing) array of ultrasound transducers is used to form a large number of received near-field focused beams within an insonated region. Since array thinning allows for unambiguous scanning or imaging over only a limited region or segment, a set of transmitters are fired one at a time to insonate one segment at a time. The receiver is an array of elements, all receiving simultaneously, and a plurality of transmitters is used, each aimed at a different segment. The transmit beam is steered by switching between transmitters, and a large number of focused receive beams are formed digitally for each transmitted pulse. The transmitters are designed to provide very little energy in the direction of the receiver spatial ambiguities or "grating lobes". Also provided is a thinned array wherein the roles of the transmitters and receivers as described above are interchanged.
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