INTELLIGIBILITY IMPROVEMENTS USING DIVERSE SUB-BAND PROCESSING APPLIED TO NOISY SPEECH

The paper presents the results of a series of experiments to assess the capability of a multi-microphone sub-band adaptive (MMSBA) signal processing scheme for improving the intelligibility of speech corrupted with noise recorded in an automobile. The noise corrupted speech signals were presented to 15 normal hearing volunteer subjects at various SNRs, and numbers and distributions of sub-bands. The results of listening tests were analysed to determine: (i) The direction and statistical significance (DSS) of any effect of processing treatment on intelligibility. (ii) The DSS of any effect of processing treatment on perceived quality. (iii) The DSS of any effect of the numbers of sub-bands used in sub-band processing (SBP). (iv) The DSS of any effect of the spacing of sub-bands used in SBP. In the experimental cases considered, the MMSBA scheme employing diverse sub-band processing is shown to deliver a statistically significant improvement in terms of both speech intelligibility and perceived quality when compared with both the wide-band processed and the noisy unprocessed case.