Effective post-processing for single-channel frequency-domain speech enhancement

Conventional frequency-domain speech enhancement filters improve signal-to-noise ratio (SNR), but also produce speech distortions. This paper describes a novel post-processing algorithm devised for the improvement of the quality of the speech processed by a conventional filter. In the proposed algorithm, the speech distortion is first compensated by adding the original noisy speech, and then the noise is reduced by a post-filter. Experimental results on speech quality show the effectiveness of the proposed algorithm in lower speech distortions. Based on our isolated word recognition experiments conducted in 15 real car environments, a relative word error rate (WER) reduction of 10.5% is obtained compared to the conventional filter.