Robust audio localization with phase unwrapping

Most of multichannel sound source Direction Of Arrival (DOA) estimation algorithms suffer from spatial aliasing problems. The phase differences between a pair of microphones are wrapped beyond the spatial aliasing frequency. A common solution is to adjust the distance between the microphones to obtain a suitable aliasing frequency, and take only the frequency band below the aliasing frequency for localization. With correct phase unwrapping, a broader frequency band can be utilized for localization. In this paper, we investigate a method for phase unwrapping solving the spatial aliasing problem for scenarios with a single source and high-level diffuse background noise (around 0dB SNR). The aliasing frequency is estimated from the signal, and is used to unwrap a phase difference vector. Pre- and post-processing steps are applied to increase the robustness. Our experiments with a large number of simulated and real signals demonstrate the robustness of our method in noise.