Using the coherence function for noise reduction

Abstract
With the development of hand-free radio communications there is great interest in noise cancelling or speech enhancement in a car. We assume that M observations are available; each one is composed of signal and noise (si+bi), and s1is the signal to be estimated. Whatever the distance between microphones is, the signals are strongly correlated, while the correlation between noises becomes rather weak for a sufficiently great distance. The coherence function is then a pertinent criterion to know whether a speech signal exists or not. The three methods presented use the coherence function to filter the observations so giving an estimate of the signal s1. The procedures presented are first shown for M = 2. Then, a generalisation of these procedures is offered. The performances of the three methods have been evaluated on real noisy speech signals by objective tests (gain on the signal-to-noise ratio, distance measures) and informal listening tests.

This publication has 0 references indexed in Scilit: