Residual echo detection based on non-causality

Abstract

Methods and systems detect residual echo in an audio signal in a non-causal manner. A non-causal residual echo detector allows accurate detection of any residual echo from an AEC (acoustic echo canceller). The non-causally detected residual echo may be utilized to perform various actions such as selecting between different causal AECs, tuning a causal AEC, and/or characterizing the performance of the causal AEC. Aspects leverage an understanding that the information about residual echo being present in a signal does not have to be causal in the sense that it is acceptable and even advantageous to know some time afterwards (e.g., after a signal has undergone acoustic echo cancellation and is output for further processing or transmission) that a residual echo was present in the signal. Such an approach is different from the case of an AEC, which needs to know right away, with a fairly low signal delay involved, whether residual echo is present.