Direct sampled I/Q beamforming: a strategy for very low cost ultrasound

We describe a new beamforming strategy designed to support the development of an extremely low cost hand held ultrasound system. Our size and cost constraints for this system are too aggressive to make conventional beamforming feasible. We propose a radical beamforming scheme, direct sampled I/Q (DSIQ) beamforming that applies focal delays only via complex rotation of data acquired by directly digitizing the RF echo data. This strategy has a very low cost in terms of digital and analog hardware. We describe the DSIQ beamformer, and discuss efficiencies in hardware implementation. We show results of experiments performed using a Philips SONOS 5500 imaging system. Theses results show that image quality is acceptable for routine applications such as intravenous line insertion.