Control of echo cancellation filters
AssigneeFrance Telecom
InventorsAlexandre Guerin, Jean-Luc Garcia
Life of this patent
Estimating the term…
Abstract
Coefficients of an adaptive filter representative of an acoustic channel between an emitted acoustic signal and a microphone signal are determined and smoothed in time. An echo is then estimated by filtering the emitted acoustic signal with the smoothed coefficients. Properties of the estimated echo and of the microphone signal are estimated. The echo cancellation filter is controlled as a function of a comparison between the properties of the estimated echo and those of the microphone signal so as to take into account the potential presence of a signal other than an echo signal in the microphone signal.
Claims21
Method of controlling an echo cancellation filter comprising:
- determining coefficients of an adaptive filter representative of an acoustic channel between an emitted acoustic signal and a microphone signal;
- smoothing in time the coefficients of said adaptive filter;
- determining an estimated echo by filtering the emitted acoustic signal with the smoothed coefficients;
- estimating properties of said estimated echo;
- estimating the same properties on the microphone signal;
- comparing said properties of the estimated echo and said properties of the microphone signal so as to evaluate the presence of a signal other than an echo signal in the microphone signal;
- and
- controlling the echo cancellation filter for cancelling an echo in the microphone signal, as a function of the comparison;
- wherein the steps of estimating properties of the estimated echo and of estimating properties of the microphone signal each comprise an auto-regressive modeling.
A computer program product for a device for controlling an echo cancellation filter, the program product comprising instructions or portions of instruction for controlling the following steps when executed by a computer of said device:
- determining coefficients of an adaptive filter representative of an acoustic channel between an emitted acoustic signal and a microphone signal;
- smoothing in time the coefficients of said adaptive filter;
- determining an estimated echo by filtering the emitted acoustic signal with the smoothed coefficients;
- estimating properties of said estimated echo;
- estimating the same properties on the microphone signal;
- comparing said properties of the estimated echo and said properties of the microphone signal so as to evaluate the presence of a signal other than an echo signal in the microphone signal;
- and
- controlling the echo cancellation filter for cancelling an echo in the microphone signal, as a function of the comparison;
- wherein the steps of estimating properties of the estimated echo and of estimating properties of the microphone signal each comprise an auto-regressive modeling.
Device for controlling an echo cancellation filter, comprising:
- means for determining coefficients of an adaptive filter representative of an acoustic channel between an emitted acoustic signal and a microphone signal;
- means for smoothing in time coefficients of said adaptive filter;
- means for determining an estimated echo by filtering the emitted acoustic signal with said smoothed coefficients;
- means for estimating properties of said estimated echo;
- means for estimating the same properties on the microphone signal;
- means for comparing said properties of the estimated echo and said properties of the microphone signal so as to evaluate the presence of a signal other than an echo signal in the microphone signal;
- and
- means for controlling the echo cancellation filter for the microphone signal as a function of said comparison;
- wherein the means for estimating properties of the estimated echo and the means for estimating properties of the microphone signal each implement auto-regressive modeling.
Device according to 11, wherein the means for estimating properties of the estimated echo further comprise means for determining a prediction residual arising from a prediction of the estimated echo by the auto-regressive model determined for said estimated echo, and the means for estimating properties of the microphone signal further comprise means for determining a prediction residual arising from a prediction of the microphone signal by the autoregressive model determined for said microphone signal.
Communication system comprising at least one terminal having a loudspeaker for emitting an acoustic signal, a microphone for sensing a microphone signal, an echo cancellation filter for compensating an acoustic channel between the emitted acoustic signal and the microphone signal, and a device for controlling the echo cancellation filter, wherein the device for controlling the echo cancellation filter comprises:
- means for determining coefficients of an adaptive filter representative of an acoustic channel between the emitted acoustic signal and the microphone signal;
- means for smoothing in time coefficients of said adaptive filter;
- means for determining an estimated echo by filtering the emitted acoustic signal with said smoothed coefficients;
- means for estimating properties of said estimated echo;
- means for estimating the same properties on the microphone signal;
- means for comparing said properties of the estimated echo and said properties of the microphone signal so as to evaluate the presence of a signal other than an echo signal in the microphone signal;
- and
- means for controlling the echo cancellation filter for the microphone signal as a function of said comparison;
- wherein the means for estimating properties of the estimated echo and the means for estimating properties of the microphone signal each implement auto-regressive modeling.
A communication terminal, comprising a loudspeaker for emitting an acoustic signal, a microphone for sensing a microphone signal, an echo cancellation filter for compensating an acoustic channel between the emitted acoustic signal and the microphone signal, and
- a controller for the echo cancellation filter, wherein the controller comprises:
- means for determining coefficients of an adaptive filter representative of an acoustic channel between the emitted acoustic signal and the microphone signal;
- means for smoothing in time coefficients of said adaptive filter;
- means for determining an estimated echo by filtering the emitted acoustic signal with said smoothed coefficients;
- means for estimating properties of said estimated echo;
- means for estimating the same properties on the microphone signal;
- means for comparing said properties of the estimated echo and said properties of the microphone signal so as to evaluate the presence of a signal other than an echo signal in the microphone signal;
- and
- means for controlling the echo cancellation filter for the microphone signal as a function of said comparison;
- wherein the means for estimating properties of the estimated echo and the means for estimating properties of the microphone signal each implement auto-regressive modeling.
Dependencies are inferred from the claim text.