InterSpeech 2021

Among different differential beamforming approaches, the minimum-norm one has received much attention as it maximizes the white noise gain(WNG). WNG measures the robustness of beamformer. But in practice, the conventional minimum-norm differential beamforming with omnidirectional elements still suffers in low white-noise-gain at the low frequencies. The major contributions of this paper are as follows: First, we extend the existing work by presenting a new solution with the use of the directional microphone elements, and show clearly the connection between the conventional beamforming and the proposed beamforming. Second, through the derivation as well as simulations, we show the proposed solution brings noticeable improvement in WNG at the low frequencies when the null positions of the directional elements coincide with the null-constraints of minimum norm solution.