Overfitting-Resistant Speech Dereverberation

This paper proposes a method that prevents the overfitting problem inherent in the joint source-channel estimation approach to speech dereverberation. The approach has several desirable attributes such as high estimation accuracy. However, the channel-related parameters estimated with the conventional implementation of this approach often overfit the source characteristics present in observed signals. This overfitting results in unstable behavior of the dereverberation process. The problem stems from the fact that the conventional implementation employs a point estimation scheme to obtain the parameters describing the source characteristics. The proposed method marginalizes the source parameters to mitigate the overfitting problem. Two kinds of experimental results are reported, one of which was obtained in a single source situation and shows the ability to prevent the overfitting; the other is obtained in a multi-source scenario indicating the applicability of the proposed method to multi-source situations.