Study and Development of the INTEL Technique for Improving Speech Intelligibility

Abstract : This report describes theoretical and experimental studies done to improve the performance of INTEL, a process for improving the signal-to-noise ratio of speech which has been corrupted by wideband noise. The theoretical study is a detailed statistical study of the process, showing how it works, why its effect on speech is different from its effect on noise, and why the cepstrum, a closely similar process, does not provide similar benefits. The experimental studies were explorations suggested by previous studies. These studies implemented various modifications to the basic process in the hope that they would improve its performance. The modifications were: Threshold clipping, Center clipping, Harmonic emphasis, and Adaptation to narrow-band speech. In addition, a number of experiments were conducted to study the effect of phase on speech intelligibility.