Acoustic beamforming through adaptive diagonal loading

Acoustic beamforming is an important technology in microphone array signal processing. It relates to the acquisition of speech signals by intelligent devices in complex environments. Acoustic beamforming is to form spatial directivity of microphone array, enhance desired signal, and suppress interference and noise. When the direction of desired signal is not accurately known, acoustic beamforming method like Frost beamforming would fail to filter interference and noise signals. This paper attempts to enhance the robustness of acoustic beamforming against inaccurate signal direction. Based on diagonal loading technique, an adaptive method is proposed to estimate signal direction. Simulation is performed on the basis of Frost beamforming method. The results show that the proposed adaptive diagonal loading method is able to suppress interference and noise signals. The signal to interference noise ratio is improved compared with non-adaptive method.