Musical Noise Removal of Enhanced Speech Using Gray Level Values of Spectrogram Plots

Enhanced speech using Power Spectral Subtraction method is computationally quite simple but results in an annoying residual noise also called musical noise due to its narrowband spectrum and presence of tone like characteristics. To eliminate this modifled spectral subtraction technique is proposed in our previous work which is based on cross terms, which were made zero in the conventional spectral subtraction method. This technique could efiectively suppress musical noise, but at the cost of speech intelligibility. To overcome this problem, a post processing technique is proposed in this paper, which is based on the gray level values of pixels in the spectrogram of enhanced speech. This method can effectively suppress musical noise without noticeable efiect on speech intelligibility. Both subjective and objective performance assessments conflrm that our method is efiective.