Ideal binary masking for reducing convolutive noise

It is important to know the degree to which convolutive noise disrupts the perceptual aspects of speech and its intelligibility. This paper presents the ideal binary masking criterion for reducing the convolutive noise (reverberation) and to improve the quality and intelligibility of speech. The noise is suppressed using ideal binary time–frequency masking that is based on signal-to-reverberation ratio (SRR) of individual time–frequency channels. All T–F channels with the SRR greater than pre-selected threshold are retained while others are eliminated. The performance of algorithm is evaluated using IEEE sentences corrupted with different degrees of reverberation times (RT₆₀) ranging from 0.3 to 2.0 s. The results indicate that with the increase of reverberation time, the intelligibility and perceptual aspects of speech decrease. Additional analyses indicated that ideal binary masking reduced the temporary envelope spreading effect introduced by the reverberation. The algorithm is evaluated with perceptual evaluation of speech quality, SNR_LOSS, log-likelihood-ratio and frequency weighted segmental signal-to-noise ratio.