Application of a Range-Doppler Algorithm to Frequency-Domain Beamforming of Ultrasound Signals

Software implementation of frequency-domain beamforming has become increasingly popular for fast imaging using ultrasound arrays. Stolt migration, which focuses aperture data in a 2-D frequency domain, has been adapted to ultrasound imaging, and can reduce beamforming time by up to two orders of magnitude compared to conventional delay-and-sum (DAS) beamforming. However, processing data in a 2-D frequency domain can require more memory to achieve sufficient accuracy and avoid interpolation errors. Here, we describe and apply the Range Doppler Algorithm (RDA) to focus ultrasound signals. RDA was first proposed for fast beamforming of monostatic data in radar remote sensing. RDA achieves image-reconstruction speed similar to Stolt migration, while all operations are done in one dimension at a time, allowing for efficient and intuitive implementation. Through simulation and phantom experiments, we show that RDA achieves similar image quality as DAS, while increasing the reconstruction speed by approximately a factor of 10.