Generating an undisturbed signal out of an audio signal including a disturbing signal

• US 20030218972A1
• Filed: 04/04/2003
• Published: 11/27/2003
• Est. Priority Date: 04/04/2002
• Status: Abandoned Application

• Current Assignee: Castel GmbH
• Original Assignee: Castel GmbH
• Inventors: Pasztor, Gabor, Nagy, Gabor, Szabo, Tamas
• Application Number:
  US10/406,446
• Publication Number:
  US 20030218972A1
• Time in Patent Office: Days
• US Class Current: 370/203
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

A method is described for generating an undisturbed signal out of an audio signal including a disturbing signal. The method comprises the steps of: estimating auto-correlation matrices and cross-correlation vectors of the equation of the Wiener filtering problem, calculating the coefficients of the solution vector of the equation of the Wiener filtering problem, evaluating the quality of the calculated coefficients, controlling the estimation step depending on the quality of the calculated coefficients, generating a correction signal out of the disturbing signal depending on the calculated coefficients, and correcting the audio signal depending on the correction signal.

Claims

1. A method of generating an undisturbed signal out of an audio signal including a disturbing signal, comprising:

estimating autocorrelation matrices and cross-correlation vectors of the equation of the Wiener filtering problem;

calculating the coefficients of the solution vector of the equation of the Wiener filtering problem;

evaluating the quality of the calculated coefficients;

controlling the estimation step depending on the quality of the calculated coefficients;

generating a correction signal out of the disturbing signal depending on the calculated coefficients; and

correcting the audio signal depending on the correction signal.

2. The method of claim 1, further comprising:

recursively conditioning the estimated autocorrelation matrices and cross-correlation vectors.

3. The method of claim 1, wherein calculating the coefficients includes dividing the hypermatrix equation of the multi-channel Wiener filtering problem into a diagonal part and some non-diagonal partitions.

4. The method of claim 3, wherein the diagonal parts are considered as Toeplitz matrices and the non-diagonal partitions are Toeplitz-like matrices.

5. The method of claim 3, wherein a fast Fourier transformation is used for matrix multiplications.

6. The method of claim 3, wherein the diagonal parts and the non-diagonal partitions result in a recursive form of the separated equations of the Wiener filtering problem.

7. The method of claim 1, wherein evaluating includes deciding whether the calculated solution vector shall be used and wherein this decision depends on the quality of the solution vector.

8. The method of claim 7, wherein an error signal is generated depending on the quality of the solution vector.

9. The method of claim 1, wherein controlling is carried out such that the quality of the Solution vector is increased.

10. The method of claim 9, wherein a feedback control signal is generated depending on the quality of the solution vector, and estimating the autocorrelation matrices and the cross-correlation vectors depending on the feedback control signal.

11. The method of claim 9, wherein a feedback control signal is generated depending on the quality of the solution vector, and recursively conditioning the autocorrelation matrices and the cross-correlation vectors depending on the feedback control signal.

12. The method of claim 1, wherein generating includes filtering the disturbing signal (X) depending on the solution vector.

13. The method of claim 12, wherein a FIR filter is provided for filtering the disturbing signal.

14. The method of claim 1, further comprising delaying the audio signal.

15. A computer program comprising computer instructions for carrying out the method of claim 1 if the computer program, is introduced into a digital computer.

16. A computer-readable medium comprising the computer program of claim 15 wherein the computer-readable medium may be introduced into a digital computer.

19. The method of claim 10, wherein a feedback control signal is generated depending on the quality of the solution vector, and recursively conditioning the autocorrelation matrices and the cross-correlation vectors depending on the feedback control signal.

17. A digital computer for generating an undisturbed signal out of an audio signal including a disturbing signal, comprising:

estimators for estimating auto-correlation matrices and cross-correlation vectors of the equation of the Wiener filtering problem;

a calculator for calculating the coefficients of the solution vector of the equation of the Wiener filtering problem, an evaluator for evaluating the quality of the calculated coefficients;

a controller for controlling the estimators depending on the quality of the calculated coefficients;

a filter for generating a correction signal out of the disturbing signal depending on the calculated coefficients; and

means for correcting the audio signal depending on the correction signal.

18. An electrical circuit for generating an undisturbed signal out of an audio signal including a disturbing signal, comprising:

estimators for estimating auto-correlation matrices and cross-correlation vectors of the equation of the Wiener filtering problem;

a calculator for calculating the coefficients of the solution vector of the equation of the Wiener filtering problem;

an evaluator for evaluating the quality of the calculated coefficients;

a controller for controlling the estimators depending on the quality of the calculated coefficients;

a filter for generating a correction signal out of the disturbing signal depending on the calculated coefficients; and

means for correcting the audio signal depending or the correction signal.