Suppression of aberration in deeper-region US images using multi-look adaptive beamforming

Multi-look techniques, such as spatial compounding and synthetic aperture, are useful to suppress unwanted aberration with improved coherence by compounding the signals of multi-transmission events. We propose a different approach for multi-look techniques involving just a single transmission event with the help of adaptive beamforming. This approach uses delay and sum output, which is constructed from one transmission event. Adaptive weights are calculated for several virtually oriented mode vector directions. We then obtain compounded output by summing the weighted signals (mode vector compounding; MVC). Because the directions are slightly away from the transmit axis, the output is expected to yield reduced multi-path signals that do not come directly from the axis of dynamic focusing. The results suggest that the effect of spatial correlation of the aberrated wave is suppressed by the compounding of mode directions. For Amplitude and Phase Estimation (APES) with MVC, the spatial resolution does not degrade because of the strong sidelobe reduction by the adaptive weights. With this approach, aberration suppression within single transmission events without the tradeoff of resolution is promising.