Role of Phase Estimation in Speech Enhancement

Typical speech enhancement algorithms that operate in the Fourier domain only modify the magnitude component. It is commonly understood that the phase component is perceptually unimportant, and thus, it is passed directly to the output. In recent intelligibility experiments, it has been reported that the Short-Time Fourier Transform (STFT) phase spectrum can provide significant intelligibility when estimated using a window function lower in dynamic range than the typical Hamming window. Motivated by this, we investigate the role of the window function for STFT phase estimation in relation to speech enhancement. Using a modified STFT Analysis-Modification-Synthesis (AMS) framework, we show that noise reduction can be achieved by modifying the window function used to estimate the STFT phase spectra. We demonstrate this through spectrogram plots and results from two objective speech quality measures.