Method and system for clear signal capture
View Patent ↗A method and system for clear signal capture comprehend several individual aspects that address specific problems in improved ways. In addition, the method and system also comprehend a hands-free implementation that is a practical solution to a very complex problem. Individual aspects comprehended related to echo and noise reduction, and divergence control.
1. A method of dynamic tracking and filter divergence control in acoustic echo cancellation (AEC) wherein a microphone signal has a near-end component and a far-end component, the microphone signal resulting from an unobservable signal corrupted by an acoustic echo (the far-end component) and being processed in an attempt to restore the unobservable signal, the acoustic echo being a speaker signal modified by an acoustic path, wherein an adaptive filter models the echo path in the frequency domain, the method comprising:
receiving the microphone signal;
applying the adaptive filter to the speaker signal to produce an echo signal that models the acoustic echo;
subtracting the echo signal from the microphone signal to produce an output signal that resembles the unobservable signal;
estimating a ratio of a far-end component energy to a total microphone signal energy;
adapting the adaptive filter based on the output signal, wherein an adaptation gain is based on the ratio to achieve a balance between dynamic tracking ability and filter divergence control,
wherein the far-end component energy is estimated based on the correlation between the microphone signal and the echo signal.
2. The method of claim 1 wherein processing takes place independently in a plurality of subbands.
3. A method of dynamic tracking and filter divergence control in acoustic echo cancellation (AEC) wherein a microphone signal has a near-end component and a far-end component, the microphone signal resulting from an unobservable signal corrupted by an acoustic echo (the far-end component) and being processed in an attempt to restore the unobservable signal, the acoustic echo being a speaker signal modified by an acoustic path, wherein an adaptive filter models the echo path in the frequency domain, the method comprising:
receiving the microphone signal;
applying the adaptive filter to the speaker signal to produce an echo signal that models the acoustic echo;
subtracting the echo signal from the microphone signal to produce an output signal that resembles the unobservable signal;
estimating a ratio of a far-end component energy to a total microphone signal energy;
adapting the adaptive filter based on the output signal, wherein an adaptation gain is based on the ratio to achieve a balance between dynamic tracking ability and filter divergence control,
wherein the far-end component energy is estimated based on the correlation between the microphone signal and the echo signal, and
wherein the adaptation gain is based on the square of the ratio of the far-end energy component to the total microphone signal energy.
4. The method of claim 3 further comprising:
utilizing an auxiliary filter parallel to the adaptive filter wherein the adaption gain is further adjusted based on the auxiliary filter to compensate possible underestimation of echo.