Improved Approach to Stereophonic Channel Decorrelation based on missing fundamental theory

摘要

Decorrelation is a well known issue in the context of Stereophonic Acoustic Echo Cancellation: it is related to the problem of uniquely identifying each pair of room acoustic paths, due to high interchannel coherence. This paper proposes an improvement to a previous work to decorrelate a stereo signal based on the missing fundamental phenomenon. An adaptive algorithm is employed to track the behavior of one of the two channels, ensuring a continuous decorrelation without affecting the stereo perception. The improvement is obtained through a constraint function, based on a sigmoid function, applied to the adaptive coefficient which controls the fundamental frequency estimation. Several results are presented, comparing our approach with a technique based on non linearity and the masked noise injection method. The comparison is done in terms of convergence speed improvement and subjective quality perception, in order to confirm the validity of the improved proposed approach.