关键词: 谱减法, 倒谱距离, 语音增强, 音乐噪声

Abstract: The basic spectral subtraction algorithm has some shortcomings under the low SNR environment, such as, poor noise reducing effect, too much residual musical noise and low speech intelligibility. An improved spectral subtraction algorithm is presented. At first, the cepstral distances of speech signal is calculated to distinguish the voice from the noise part. In this process, a dynamical calculation value of noise is adopted in the improved algorithm while the basic algorithm uses a statistical mean value. Then according to the ratio of cepstral distance of current frame to noise frame, it can set a dynamical spectral values coefficient, which avoids the shortcomings caused by the unchanged coefficient in basic algorithm. Finally, three methods are proposed to reduce the musical noise. The numerical results show that the improved algorithm can reduce noise effectively, and also enhance speech intelligibility, which can meet the demand of speech enhancement.

Key words: spectral subtraction, cepstral distance, speech enhancement, musical noise