Time-frequency constraints for phase estimation in single-channel speech enhancement

Previous single-channel speech enhancement algorithms often employ noisy phase while reconstructing the enhanced signal. In this paper, we propose novel phase estimation methods by employing several temporal and spectral constraints imposed on the phase spectrum of speech signal. We pose the phase estimation problem as estimating the unknown clean speech phase at sinusoids observed in additive noise. To resolve the ambiguity in phase estimation problem, we introduce individual time-frequency constraints: group delay deviation, instantaneous frequency deviation, and relative phase shift. Through extensive simulations, the effectiveness of the proposed phase estimation methods in single-channel speech enhancement is demonstrated. Employing the estimated phase for signal reconstruction in medium-to-high SNRs leads to consistent improvement in perceived quality compared to when noisy phase is used.