Phase Processing for Single-Channel Speech Enhancement: History and recent advances
Many short-time Fourier transform (STFT) based single-channel speech enhancement algorithms are focused on estimating the clean speech spectral amplitude from the noisy observed signal in order to suppress the additive noise. To this end, they utilize the noisy amplitude information and the corresponding a priori and a posteriori SNRs while they employ the observed noisy phase when reconstructing enhanced speech signal. This paper presents two contributions: i) reconsidering the relation between the phase group delay deviation and phase deviation, and ii) proposing a closed-loop single-channel speech enhancement approach to estimate both amplitude and phase spectra of the speech signal. To this end, we combine a group-delay based phase estimator with a phase-aware amplitude estimator in a closed loop design. Our experimental results on various noise scenarios show considerable improvement in the objective perceived signal quality obtained by the proposed iterative phase-aware approach compared to conventional Wiener filtering which uses the noisy phase in signal reconstruction.