Binary Mask Estimation for Improved Speech Intelligibility in Reverberant Environments

A blind (non-ideal) time-frequency (T-F) masking technique is proposed for suppressing reverberation. A binary mask is estimated at each T-F unit by extracting a single variance-based feature from the reverberant signal and comparing its value against an adaptive threshold. The performance of the estimated binary mask is evaluated using intelligibility listening tests with hearing impaired listeners in four moderate to highly reverberant conditions. Results indicated that the proposed T-F masking technique yielded significant improvements in intelligibility even in highly reverberant conditions (T-60 = 1.0 s). This improvement was attributed to the recovery of the vowel/consonant boundaries which are severely smeared in reverberation.