β-order MMSE spectral amplitude estimation for speech enhancement

This paper proposes β-order minimum mean-square error (MMSE) speech enhancement approach for estimating the short time spectral amplitude (STSA) of a speech signal. We analyze the characteristics of the β-order STSA MMSE estimator and the relation between the value of β and the spectral amplitude gain function of the MMSE method. We further investigate the effectiveness of a range of fixed-β values in estimating STSA based on the MMSE criterion, and discuss how the β value could be adapted using the frame signal-to-noise ratio (SNR). The performance of the proposed speech enhancement approach is then evaluated through spectrogram inspection, objective speech distortion measures and subjective listening tests using several types of noise sources from the NOISEX-92 database. Evaluation results show that our approach can achieve a more significant noise reduction and a better spectral estimation of weak speech spectral components from a noisy signal as compared to many existing speech enhancement algorithms.