On robust and high directive beamforming with small-spacing microphone arrays for scattered sources

This paper is devoted to beamforming with small-spacing microphone arrays for processing broadband and scattered acoustic sources. It presents a maximum diffuse noise gain (MDNG) beamformer in this context using the joint diagonalization technique, which is effective in suppressing diffuse and directional noise, but at a price of low white noise gain (WNG). We also introduce a maximum WNG (MWNG) beamformer, which is robust to the array imperfections, but paying a price of sacrificing the diffuse noise gain (DNG). To make a tradeoff between WNG and DNG so that the beamformer, on the one hand, can achieve high directivity and, on the other hand, is robust to implement, we propose a generalized MDNG beamformer, which includes both the MDNG and MWNG beamformers as particular cases. Simulations are conducted to illustrate the properties and advantages of the proposed beamformers.