Speaker Direction-of-Arrival Estimation Based on Frequency-Independent Beampattern

The differential microphone array (DMA) becomes more and more popular recently. In this paper, we derive the relationship between the direction-of-arrival (DoA) and DMA’s frequencyindependent beampatterns. The derivation demonstrates that the DoA can be yielded by solving a trigonometric polynomial. Taking the dipoles as a special case of this relationship, we propose three methods to estimate the DoA based on the dipoles. However, we find these methods are vulnerable to the axial directions under the reverberation environment. Fortunately, they can complement each other owing to their robustness to different angles. Hence, to increase the robustness to the reverberation, we proposed another new approach by combining the advantages of these three dipole-based methods for the speaker DoA estimation. Both simulations and experiments show that the proposed method not only outperforms the traditional methods for small aperture array but also is much more computationally efficient with avoiding the spatial spectrum search.