A pitch-based model for separation of reverberant speech

In everyday listening, both background noise and reverberation degrade the speech signal. While monaural speech separation based on periodicity has achieved considerable progress in handling additive noise, little research has been devoted to reverberant scenarios. Reverberation smears the harmonic structure of speech signals, and our evaluations using a pitch-based separation algorithm show that an increase in the room reverberation time causes degradation in performance due to the loss in periodicity for the target signal. We propose a two-stage monaural speech separation system that combines the inverse filtering of the room impulse response corresponding to target location with a pitch-based speech segregation method. As a result of the first processing stage, the harmonicity of a signal arriving from target direction is partially restored while signals arriving from other locations are further smeared, and this leads to improved separation. A systematic evaluation shows that the proposed system results in considerable signal-to-noise ratio gains across different conditions. 1