A comparative study between different pre-whitening decorrelation based acoustic feedback cancellers

The use of an adaptive feedback canceller (AFC) based on signals pre-whitening/filtering in hearing aids seems very attractive, since it limits desired signal degradation when amplification gain is increased. In this paper, we present a comparative assessment of the performances of some existing pre-whitening decorrelation based methods. The used criteria consider the adaptive filter performances, the system stability and the speech quality in terms of distortion and oscillation. Results show that the method including the loudspeaker pre-whitening and the microphone filtering is the best. Moreover, the use of an adequate algorithm for adaptive pre-whitener based on the minimization of a criterion which considers the inter-correlation between the pre-whitened loudspeaker and the filtered microphone signals improves more the performances.