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US 8,284,949 B2Granted
Multi-channel acoustic echo cancellation system and method
AssigneeUniversity of Utah Research Foundation
InventorsBehrouz Farhang, Harsha I. K. Rao
Life of this patent
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Abstract
Techniques for multi-channel acoustic echo cancellation include adaptive filtering. An adaptive filter can use a lattice predictor of order M coupled to an adaptive LMS/Newton filter of length N, wherein M<N. The lattice predictor can provide decorrelation of the input to the LMS/Newton filter and can provide faster convergence for the LMS/Newton filter. Efficient operation of the LMS/Newton filter can also be provided by using output from the lattice predictor to provide low complexity update of weights for the LMS/Newton filter.
Claims20
A multi-channel acoustic echo cancellation system comprising:
- a plurality of first microphones disposed within a first acoustic space and configured to generate a plurality of first electronic signals, the plurality of first electronic signals derived from acoustic signals received from a first acoustic source within the first acoustic space;
- a plurality of speakers disposed within a second acoustic space and coupled to the plurality of first microphones to generate a plurality of second acoustic signals corresponding to the plurality of first electronic signals;
- a plurality of second microphones disposed within the second acoustic space and configured to generate a plurality of second electronic signals, the second electronic signals derived from acoustic signals received from a second acoustic source within the second acoustic space and echoes of the plurality of second acoustic signals generated within the second acoustic space;
- and
- an adaptive filter coupled to the plurality of second microphones and configured to adaptively filter the plurality of second electronic signals to form a plurality of echo-reduced second electronic signals using the plurality of first electronic signals as a reference, wherein the adaptive filter comprises a lattice predictor of order M configured to provide an error-prediction vector and reflection coefficient data to an LMS/Newton adaptive filter of length N, wherein M<N, said multi-channel acoustic echo cancellation system further configured such that the plurality of second electronic signals are input into a backward error predictor and the output of the backward predictor is input into a forward prediction error filter and the output of the forward prediction error filter corresponds to a u vector representing a multiplication of the inverse of a correlation matrix and a signal vector, thereby precluding the need to derive an inverse of the correlation matrix.
2 more elements
A method of multi-channel acoustic echo cancellation, comprising:
- forming a plurality of first electronic signals by transducing a plurality of acoustic signals received at a plurality of differing locations within a first acoustic space, the acoustic signals being received from a first acoustic source within the first acoustic space;
- converting each of the plurality of first electronic signals into a corresponding one of a plurality of second acoustic signals at a plurality of differing locations within a second acoustic space, the second acoustic space being different from the first acoustic space;
- forming a plurality of second electronic signals by transducing acoustic signals received at a plurality of differing locations within the second acoustic space, the acoustic signals comprising acoustic signals received from a second acoustic source within the second acoustic space and echoes of the plurality of second acoustic signals within the second acoustic space;
- and
- performing an adaptive filtering operation on the plurality of second electronic signals using the plurality of first electronic signals as a reference input to form a plurality of echo-reduced second electronic signals, wherein the adaptive filtering operation comprises forming a plurality of decorrelated signals using a lattice predictor and using the plurality of decorrelated signals in a LMS/Newton adaptive filter,
- wherein said multi-channel acoustic echo cancellation system is further configured such that the plurality of second electronic signals are input into a backward error predictor and the output of the backward predictor is input into a forward prediction error filter and the output of the forward prediction error filter corresponds to a u vector representing a multiplication of the inverse of a correlation matrix and a signal vector, thereby precluding the need to derive an inverse of the correlation matrix.
3 more elements
A system for multi-channel acoustic echo cancellation, comprising:
- means for forming a plurality of first electronic signals by transducing a plurality of acoustic signals received at a plurality of differing locations within a first acoustic space, the acoustic signals received from a first acoustic source within the first acoustic space;
- means for converting each of the plurality of first electronic signals into a corresponding one of a plurality of second acoustic signals at a plurality of differing locations within a second acoustic space, the second acoustic space being different from the first acoustic space;
- means for forming a plurality of second electronic signals by transducing acoustic signals received at a plurality of differing locations within the second acoustic space, the acoustic signals comprising acoustic signals received from a second acoustic source within the second acoustic space and echoes of the plurality of second acoustic signals within the second acoustic space;
- means for forming a plurality of decorrelated signals from the second electronic signals using the plurality of first electronic signals as a reference input;
- and
- means for using the plurality of decorrelated signals in a LMS/Newton adaptive filter to form a plurality of echo-reduced second electronic signals,
- wherein said multi-channel acoustic echo cancellation system is further configured such that the plurality of second electronic signals are input into a backward error predictor and the output of the backward predictor is input into a forward prediction error filter and the output of the forward prediction error filter corresponds to a u vector representing a multiplication of the inverse of a correlation matrix and a signal vector, thereby precluding the need to derive an inverse of the correlation matrix.
4 more elements
Dependencies are inferred from the claim text.