Inter-channel decorrelation by sub-band resampling in frequency domain

This paper presents a novel decorrelation procedure by frequency-domain resampling in sub-bands. The new procedure expands on the idea of resampling in the frequency domain that efficiently and effectively alleviates the non-uniqueness problem for a multi-channel acoustic echo cancellation system while introducing minimal distortion to the signal. We show in theory and verify experimentally that the amount of decorrelation in each sub-band, measured in terms of the coherence, can be controlled arbitrarily by varying the resampling ratio per frequency bin. For perceptual evaluation, we adjust the sub-band resampling ratios to match the coherence given by other decorrelation procedures. The speech quality (PESQ) score from the proposed decorrelation procedure remains high at around 4.5, which is about the highest possible PESQ score after signal modification.