Robust beamforming in the STFT domain based on constrained minimum power combination

Beamforming is a powerful technique for spatial interference suppression. However, in practical applications, there always exists a trade-off issue between the directivity capability of an array and its robustness on spatial white noise. In this paper, in order to combine the robustness merit of the delay-and-sum beamformer and the high directional gain merit of the superdirective beamformer, we propose a constrained minimum-power combination method. This approach can automatically select the best beamformer during processing so as to control the unwanted white noise amplification and keep the maximum directivity factor if possible. The performance on the robustness and the directional gain are evaluated in ideal and complicated acoustic fields respectively. The results verify that the proposed beamformer always achieves the best performance comparing to other popular beamformers.