Abstract: The focused beamformer is an efficient broadband beamforming method because of the advantages of the ability to operate in multipath environments and computational efficiency. However, the robustness of the focused beamformer is not good enough when the error of signal direction exists. To overcome the shortcoming, a novel robust broadband beamforming method based on the focusing approach is presented in this paper to achieve a constant beamwidth for acoustic imaging. The proposed method mainly applies the idea of Robust Capon Beamforming (RCB) to the focusing approach to get the more exact focusing transformation matrix and then reduce the focused data error. Thus it can greatly improve the robustness performance of the focused beamformer.

Key words: constant-beamwidth, acoustic imaging, focusing beamforming, RCB, RSS