Fourier-Domain Beamforming and Sub-Nyquist Sampling for Coherent Pixel-Based Ultrasound Imaging

Coherent pixel-based beamforming has been developed for generating uniform high-resolution ultrasound images. It is based on the conventional architecture of ultrasonic systems using fixed-focused beams to acquire data. The image generation, however, is time-consuming as it requires data superposition from a large number of transmits. In this study, we integrate a frequency-domain beamforming framework with pixel-based beamforming, which allows image generation with a sub-Nyquist sampling of the radio-frequency (RF) echo signals. With this sub-Nyquist sampling technique, the front-end sampling system can work at a much lower rate to get the required bandwidth of RF echo signals. As a result, the proposed beamformer can offer almost comparable image resolution and contrast with coherent pixel-based beamforming with a 9-fold sampling reduction. The experimental results demonstrated the performance of the proposed beamformer, showing its potential in applications on low-power consumption and small-size ultrasound systems.