Front–End Architecture Design for Low-Complexity 3-D Ultrasound Imaging Based on Synthetic Aperture Sequential Beamforming

The 3-D ultrasound imaging provides distinct advantages over its 2-D counterpart leading to a more accurate analysis of tumors and cysts. However, the front end of a 3-D system must receive and process data at prodigious rates, making it impractical for power-constrained portable systems. Synthetic aperture sequential beamforming (SASB) is an ultrasound beamforming technique that splits the computation into two stages, such that the computation in Stage 1 can be completed in the power-constrained front end while the remaining computation can be done elsewhere. In this article, we present several algorithmic and architectural techniques to enable efficient computation of Stage 1 processing without compromising imaging quality. Specifically, we present algorithmic techniques that reduce the computational complexity in Stage 1 by 17× through a systematic reduction in the number of apodization coefficients. We propose a 3-D die stacked architecture where the signals received by 961 active transducers are digitized, routed by a network-onchip, and processed in parallel. This architecture does not require the explicit storage of incoming data samples. We synthesize the architecture using TSMC 28-nm technology node. The front-end power consumption is around 1.5 W, making it suitable for portable applications.