Fast and Accurate Acoustic-Coupling Level Estimation for Echo Reduction

This paper introduces a new acoustic-coupling level (ACL) estimation method for an echo reduction based on Wiener filtering. This method employs two techniques: 1) a fast and robust ACL estimation using a short-time correlation between received and microphone input signals in time and frequency spectral domains and 2) compensation of the ACL estimation error caused by the inaccurate correlation obtained when applying the fast Fourier transform (FFT) with a short finite frame length. The proposed ACL estimation method continuously updates the estimated ACL and immediately tracks a rapid echo-path change even during double-talk periods. The performance with this method is demonstrated by simulation results in which the better acoustic-coupling level is obtained than the conventional method, the undesired echo is sufficiently suppressed, and the speech distortion is decreased.

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