Frequency Depended Spectral Subtraction For Speech Enhancement

The corruption of speech due to presence of additive background noise causes severe difficulties in various communications environments. This paper addresses the problem of reduction of additive background noise in speech. The proposed approach is a frequency dependent speech enhancement method based on the proven spectral subtraction method. Most implementations and variations of the basic spectral subtraction technique advocate subtraction of the noise spectrum estimate over the entire speech spectrum. However real world noise is mostly colored and does not affect the speech signal uniformly over the entire spectrum. In this paper, new spectral subtraction method proposed which takes into account the fact that colored noise affects the speech spectrum differently at various frequencies. This method provides a greater degree of flexibility and control on the noise subtraction levels that reduces artifacts in the enhanced speech, resulting in improved speech quality. This method outperforms the conventional spectral subtraction method with respect to speech quality and reduced musical noise.