Multi-channel echo cancellation with round robin regularization
First Claim
1. A method for canceling echo of a plurality of playback signals in a captured signal, comprising:
- decomposing the plurality of playback signals into a plurality of subband signals;
applying a plurality of adaptive filters each having an inverse correlation matrix to the plurality of subband signals;
selecting each of the plurality of adaptive filters in a round robin sequence;
regularizing the inverse correlation matrix of each selected adaptive filter, regularizing the inverse correlation matrix further comprising;
inverting the inverse correlation matrix to produce a correlation matrix;
regularizing the correlation matrix to produce a regularized correlation matrix;
obtaining a regularized inverse correlation matrix by inverting the regularized correlation matrix; and
reducing the echo in the captured signal using the outputs of the adaptive filters.
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Abstract
A method and system of multi-channel echo cancellation using round robin regularization. The multi-channel round robin regularization echo cancellation method includes applying a plurality of adaptive filters, each having an inverse correlation matrix, to the multi-channel playback signal. Each of the plurality of adaptive filters is selected in a round robin sequence, so that every round each of the filters is selected. The inverse correlation matrix associated with each selected adaptive filter then is regularized as needed. The regularized adaptive filter then is used to remove the echo of the multi-channel playback signal from a captured signal. Regularization is implemented in a round robin manner to ensure that each subband is selected so that the adaptive filter for that subband can be examined. Other features of the multi-channel echo cancellation system and method include dynamic switching between monaural and multi-channel echo cancellation and mixed processing for lower and upper subbands.
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Citations
34 Claims
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1. A method for canceling echo of a plurality of playback signals in a captured signal, comprising:
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decomposing the plurality of playback signals into a plurality of subband signals; applying a plurality of adaptive filters each having an inverse correlation matrix to the plurality of subband signals; selecting each of the plurality of adaptive filters in a round robin sequence; regularizing the inverse correlation matrix of each selected adaptive filter, regularizing the inverse correlation matrix further comprising; inverting the inverse correlation matrix to produce a correlation matrix; regularizing the correlation matrix to produce a regularized correlation matrix; obtaining a regularized inverse correlation matrix by inverting the regularized correlation matrix; and reducing the echo in the captured signal using the outputs of the adaptive filters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A computer-implemented method for eliminating echoes of a plurality of playback signals in a captured signal, comprising:
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decomposing the plurality of playback signals into subbands; processing the subbands using a recursive least squares (RLS) adaptive filter for each of the subbands; selecting each of the RLS adaptive filters in round robin scheme; regularizing the selected RLS adaptive filter to ensure stability, regularizing the selected RLS adaptive filters further comprising; computing a correlation matrix of the RLS adaptive filter by inverting an inverse correlation matrix; regularizing a correlation matrix of the RLS adaptive filter to obtain a regularized correlation matrix; computing a regularized inverse correlation matrix of the RLS adaptive filter from the regularized correlation matrix; and reducing echoes in the captured signal using the outputs of the RLS adaptive filters. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for automatically switching between two different types of echo cancellation processes when processing one or more playback signals and a captured signal containing echo, comprising:
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detecting whether the one or more playback signals is monaural; processing the captured signal and the one or more playback signals using a monaural echo cancellation process if the one or more playback signals are monaural; processing the captured signal and the one of more playback signals using a multi-channel round robin regularization echo cancellation process if the one or more playback signals are not monaural; using an estimation technique to estimate a correlation matrix for the multi-channel round robin regularization echo cancellation process, using the estimation technique further comprising one of; (a) solving a normal equation in a statistical manner using a method of steepest descent when dynamically switching from the multi-channel round robin regularization echo cancellation process to the monaural echo cancellation process; (b) solving the normal equation deterministically using a least squares process when dynamically switching from the monaural echo cancellation process to the multi-channel round robin regularization echo cancellation process; and dynamically switching between the monaural echo cancellation process and the multi-channel round robin regularization echo cancellation process whenever the detection changes from one type to another. - View Dependent Claims (26, 27, 28, 29)
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30. A process for canceling echoes of a plurality of playback signals in a captured signal, the captured signal comprising lower captured subbands containing lower frequencies of the captured signal and higher captured subbands containing higher frequencies of the captured signal and the plurality of playback signals comprising lower playback subbands containing lower frequencies of the plurality of playback signals and higher playback subbands containing higher frequencies of the plurality of playback signals, the process comprising:
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using a first echo cancellation process to cancel echoes from the upper captured subbands; and using a multi-channel round robin regularization echo cancellation process to cancel the echoes in the lower captured subbands, the multi-channel round robin regularization echo cancellation process further comprising; applying a plurality of adaptive filters, which are recursive least square (RLS) adaptive filters and each of the plurality of adaptive filters comprising an inverse correlation matrix, to each of the lower playback subbands; selecting each of the plurality of adaptive filters in a round robin sequence; regularizing the inverse correlation matrix of each selected adaptive filter; computing each correlation matrix from an inverse correlation matrix. - View Dependent Claims (31, 32, 33, 34)
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Specification