Binaural speech enhancement with instantaneous coherence smoothing using the cepstral correlation coefficient

In this paper we propose a novel approach to cepstral smoothing for reducing musical noise fluctuations in binaural speech enhancement. Similar to other methods, our approach computes a preliminary spectral gain function using the magnitude-squared coherence function and applies an instantaneous weighting to the gain function in the cepstral domain. In this contribution, the weighting function is based on the binaural cepstral correlation coefficient (CCC). We introduce the CCC and briefly discuss its properties. Similar to the cepstrum, the CCC emphasizes the spectral envelope and fundamental frequency information of the target signal, however, in a representation normalized to a range of [-1,1] and less sensitive to spatially uncorrelated noise. Thus, it can be easily and effectively used as a weight in the cepstral domain. The utility of the CCC is confirmed via experiments with different noise types and several instrumental measures.