Method for determining a noise reference signal for noise compensation and/or noise reduction
View Patent ↗The invention provides a method for determining a noise reference signal for noise compensation and/or noise reduction. A first audio signal on a first signal path and a second audio signal on a second signal path are received. The first audio signal is filtered using a first adaptive filter to obtain a first filtered audio signal. The second audio signal is filtered using a second adaptive filter to obtain a second filtered audio signal. The first and the second filtered audio signal are combined to obtain the noise reference signal. The first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal.
1. A computer implemented method for determining a noise reference signal for noise compensation, comprising:
in a first computer process, receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
in a second computer process, filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
in a third computer process, filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
in a fourth computer process, combining the first and the second filtered audio signal to obtain the noise reference signal;
wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal;
wherein a first transfer function models a transfer from a wanted signal originating from a wanted sound source to the first signal path and a second transfer function models a transfer from the wanted signal originating from the wanted sound source to the second signal path, and wherein the transfer function of the first adaptive filter is based on the second transfer function and wherein the transfer function of the second adaptive filter is based on the first transfer function.
2. The computer implemented method according to claim 1 , further comprising:
in a computer process, adapting the first and the second adaptive filter.
3. The computer implemented method according to claim 2 , wherein adapting the first and the second adaptive filter is based on a normalized least mean square method.
4. The computer implemented method according to claim 3 , wherein the normalized least mean square method comprises modifying a set of filter coefficients of the first and/or second adaptive filter based on the power or power density of the first and second audio signal.
5. The computer implemented method according to claim 2 wherein adapting the first and second adaptive filter is based on a minimization of the signal-to-noise ratio of the noise reference signal.
6. The computer implemented method according to claim 5 , wherein the method based on the minimization of the signal-to-noise ratio comprises determining a power or power density of the first and the second audio signal.
7. The computer implemented method according to claim 5 , wherein the method based on the minimization of the signal-to-noise ratio comprises determining a power or power density of the noise component of the first and second audio signal.
8. The computer implemented method according to claim 5 , wherein minimizing the signal-to-noise ratio of the noise reference signal is based on the power or power density of the first and the second audio signal and on the power or power density of the noise component of the first and second audio signal.
9. A computer implemented method for determining a noise reference signal for noise compensation, comprising:
in a first computer process, receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
in a second computer process, filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
in a third computer process, filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
in a fourth computer process, combining the first and the second filtered audio signal to obtain the noise reference signal;
wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal;
in a computer process, adapting the first and the second adaptive filters based on a normalized least mean square method wherein the normalized least mean square method comprises modifying a set of filter coefficients of the first and/or second adaptive filter based on the noise reference signal.
10. A computer implemented method for determining a noise reference signal for noise compensation, comprising:
in a first computer process, receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
in a second computer process, filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
in a third computer process, filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
in a fourth computer process, combining the first and the second filtered audio signal to obtain the noise reference signal;
wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal;
in a computer process, adapting the first and the second adaptive filter wherein adapting the first and the second adaptive filter comprises normalizing modified filter coefficients of the first and/or second adaptive filter using a predetermined normalization factor.
11. The computer implemented method according to claim 10 , wherein the predetermined normalization factor is based on one or more filter coefficients or on one or more modified filter coefficients of the first and/or second adaptive filter.
12. A computer implemented method for determining a noise reference signal for noise compensation, comprising:
in a first computer process, receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
in a second computer process, filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
in a third computer process, filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
in a fourth computer process, combining the first and the second filtered audio signal to obtain the noise reference signal;
wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal wherein the first and the second audio signal each are a beamformed signal, emanating from different beamformers.
13. A computer implemented method for determining a noise reference signal for noise compensation, comprising:
in a first computer process, receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
in a second computer process, filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
in a third computer process, filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
in a fourth computer process, combining the first and the second filtered audio signal to obtain the noise reference signal;
wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal wherein combining the first and the second filtered audio signal comprises subtracting the first filtered audio signal from the second filtered audio signal.
14. A computer implemented method for processing an audio signal for noise compensation, comprising:
in a first computer process, receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
in a second computer process, filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
in a third computer process, filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
in a fourth computer process, combining the first and the second filtered audio signal to obtain the noise reference signal;
wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal;
filtering the noise reference signal on the second signal path using a third adaptive filter to obtain a filtered noise reference signal; and
combining the first audio signal from the first signal path and the filtered noise reference signal to obtain an output signal with reduced noise.
15. A computer program product including computer code on a non-transitory computer readable storage medium for determining a noise reference signal for noise compensation, the computer code comprising:
computer code for receiving a first audio signal on a first signal path and a second audio signal on a second signal path;
computer code for filtering the first audio signal using a first adaptive filter to obtain a first filtered audio signal;
computer code for filtering the second audio signal using a second adaptive filter to obtain a second filtered audio signal; and
computer code for combining the first and the second filtered audio signal to obtain the noise reference signal; wherein the first and the second adaptive filter are adapted such as to minimize a wanted signal component in the noise reference signal;
wherein a first transfer function models a transfer from a wanted signal originating from a wanted sound source to the first signal path and a second transfer function models a transfer from the wanted signal originating from the wanted sound source to the second signal path, and wherein the transfer function of the first adaptive filter is based on the second transfer function and wherein the transfer function of the second adaptive filter is based on the first transfer function.
16. The computer program product according to claim 15 , further comprising:
computer code for adapting the first and the second adaptive filter.
17. The computer program product according to claim 16 , wherein the computer code for adapting the first and the second adaptive filter is based on a normalized least mean square method.
18. The computer program product according to claim 17 , wherein the computer code for the normalized least mean square method comprises computer code for modifying a set of filter coefficients of the first and/or second adaptive filter based on the noise reference signal.
19. The computer program product according to claim 17 , wherein the computer code for the normalized least mean square method comprises computer code for modifying a set of filter coefficients of the first and/or second adaptive filter based on the power or power density of the first and second audio signal.
20. The computer program product according to claim 17 , wherein the computer code for adapting the first and the second adaptive filter comprises computer code for normalizing modified filter coefficients of the first and/or second adaptive filter using a predetermined normalization factor.
21. The computer program product according to claim 16 wherein the computer code for adapting the first and second adaptive filter is based on a minimization of the signal-to-noise ratio of the noise reference signal.
22. The computer program product according to claim 21 , wherein the computer code for the method based on the minimization of the signal-to-noise ratio comprises computer code for determining a power or power density of the first and the second audio signal.
23. The computer program product according to claim 21 , wherein computer code for the method based on the minimization of the signal-to-noise ratio comprises computer code for determining a power or power density of the noise component of the first and second audio signal.
24. The computer program product according to claim 21 , wherein the computer code for minimizing the signal-to-noise ratio of the noise reference signal is based on the power or power density of the first and the second audio signal and on the power or power density of the noise component of the first and second audio signal.
25. A computer program product having computer code on a non-transitory computer readable storage medium, the computer code executable on a computer for processing an audio signal for noise compensation, computer code comprising:
computer code for determining a noise reference signal according to claim 15 , using a first audio signal on a first signal path and a second audio signal on a second signal path;
computer code for filtering the noise reference signal on the second signal path using a third adaptive filter to obtain a filtered noise reference signal; and computer code for combining the first audio signal from the first signal path and the filtered noise reference signal to obtain an output signal with reduced noise.