Direct-Path Signal Cross-Correlation Estimation for Sound Source Localization in Reverberation

Sound source localization (SSL) is challenging in presence of reverberation since the cross-correlation between the direct-path signals in different microphones, which indicates the spatial information of the sound source, is interfered by the reverberation signal components. A novel algorithm is proposed in this paper to estimate the cross-correlation of the direct-path speech signals, such that the robustness of SSL to reverberation can be improved. The proposed method follows a similar scheme to the multichannel linear prediction (MCLP), which is commonly used for speech dereverberation, while avoids the explicit estimation of the direct-path signal of each channel. This is achieved by revealing the relationship between the direct-path signal cross-correlation (DPCC) and the MCLP coefficient vector, and finally deriving the DPCC by using only the multichannel reverberant signals. It is also shown that the pre-whitening operation, which is widely used for SSL, can be inherently integrated into the estimated DPCC. An adaptive method is further derived to facilitate online frame-level SSL. The proposed method can be easily applied to conventional cross-correlation based SSL methods by using the DPCC rather than the full cross-correlation. Experiments conducted in various reverberant conditions demonstrate the effectiveness of the proposed method.