A new multi-beam approach to real-time 3-D imaging

In this paper we propose a new beamforming approach for real-time 3-D imaging, called Multi-Transmit Synthetic Aperture (MTSA). In this approach multiple simultaneous beams are spread evenly across the imaged region, using a subset of elements to form each beam. The beamformer was implemented for a 143 element array using four Field Programmable Gate Arrays (FPGA). An approximate expression for the round trip time of flight between each transmit and receive element was developed to simplify the calculation of the beamforming delays. Linear interpolation was used to limit time quantization effects. The design was tested by comparing computer simulations of the gate array design with a theoretical model of the beamformer.