Multi-Speaker Direction of Arrival Estimation using SRP-PHAT Algorithm with a Weighted Histogram

A direction of arrival (DOA) estimator for concurrent speakers in a reverberant environment is presented. The DOA estimation task is formulated in the short-time Fourier transform (STFT) in two stages. In the first stage, a single narrow-band DOA per time-frequency (T-F) is selected, since the speech sources are assumed to exhibit disjoint activity in the STFT domain. The narrow-band DOA is obtained as the maximum of the narrow-band steered response power phase transform (SRP-PHAT) localization spectrum at that T-F bin. In addition, for each narrow-band DOA, a quality measure is calculated, which provides the confidence in the estimated decision. In the second stage, the wide-band localization spectrum is calculated using a weighted histogram of the narrow-band DOAs with the quality measures as weight. Finally, the wide-band DOA estimation is obtained by selecting the peaks in the wide-band localization spectrum. The results of our experimental study demonstrate the benefit of the proposed algorithm as compared to the wide-band SRP-PHAT algorithm in a reverberant environment.