• Title/Summary/Keyword: Stereo acoustic echo canceller

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Post Processing using Blind Signal Separation in Stereo Acoustic Echo Canceller (스테레오 음향반향제거기의 BSS 후처리방법)

  • Lee, Haeng Woo
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.10 no.1
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    • pp.131-138
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    • 2014
  • This paper is on a stereo acoustic echo canceller with the blind signal separation for post processing. The convergence speed of the stereo acoustic echo canceller is deteriorated due to mixing two residual signals which are update signals of each echo canceller. To solve this problem, we are to use the blind signal separation(BSS) method separating the mixed signals after the echo cancellers. The blind signal separation method can extracts the source signals by means of the iterative computations with two input signals. We had verified performances of the proposed acoustic echo canceller for stereo through simulations. The results of simulations show that the acoustic echo canceller for stereo using this algorithm operates stably without divergence in the normal state. And, when the speech signals were inputted, this echo canceller achieved about 2dB higher ERLE with the BSS post processing method than without this method. This stereo echo canceller showed the best performance in the case of inputting the real voice signal.

An Acoustic Echo Canceller for Stereo Using Blind Signal Separation (암묵신호분리를 이용한 스테레오 음향반향제거기)

  • Lee, Haeng Woo
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.8 no.3
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    • pp.125-131
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    • 2012
  • This paper is on a stereo acoustic echo canceller with the blind signal separation. The convergence speed of the stereo acoustic echo canceller is deteriorated due to mixing two residual signals in the update signal of each echo canceller. To solve this problem, we are to use the blind signal separation(BSS) method separating the mixed signals. The blind signal separation method can extracts the source signals by means of the iterative computations with two input signals. We had verified performances of the proposed acoustic echo canceller for stereo through simulations. The results of simulations show that the acoustic echo canceller for stereo using this algorithm operates stably without divergence in the normal state. And, when the speech signals were inputted, this echo canceller achieved about 3dB higher ERLE in the case of using the BSS algorithm than the case of not using the BSS algorithm. But this echo canceller didn't get good performances in the case of inputting the white noises as stereo signals.

Pseudo Stereophonic Acoustic Echo Canceller using Hyper-plane Projection Algorithm (Hyper-plane투영 알고리듬을 이용한 의사 스테레오 음향 반향 제거기)

  • 박필구;이원철
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.6
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    • pp.17-30
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    • 1999
  • This paper proposes a new stereophonic acoustic echo canceller to prevent impairments on the voice quality and to remove acoustic echo effectively appearing in stereo environment at the instant of abrupt change of the transmission room environment in teleconferencing system. In stereophonic acoustic echo canceller, the major defective problems are the large computational complexity of estimating echo path systems due to the long impulse response of the true echo paths and the performance degradation of echo canceller due to large correlation between dual stereo signals. Moreover, the change of the suboptimal solution for the echo canceller was considered as a critical deficient factor on to the performance of stereophonic echo canceller. To overcome these problems, this paper proposes pseudo stereophonic acoustic echo canceller using Hyper-plane projection algorithm, which shows the robustness to the environment change of the transmission room and the efficiency of computational complexity.

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Performance Improvement of Stereo Acoustic Echo Canceler Using Gram-Schmidt Orthogonality Principle (그람-슈미트 (Gram-Schmidt) 직교원리를 이용한 스테레오 음향 반향 제거기의 성능향상)

  • 김현태;박장식;손경식
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.5
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    • pp.28-34
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    • 2001
  • In stereo acoustic echo canceller scheme, coefficients of adaptive filter converge very slowly or misconverge to real acoustic echo path in receiving room. This is due to cross-correlation in stereo signals. In this paper, a new preprocess algorithm is proposed to improve the performance of stereo AEC(acoustic echo canceller) without computational burden. The proposed algorithm reduces cross-correlation using Gram-Schmidt orthogonality principles and nonlinear filtering. Computer simulations demonstrate that this algorithm performs well compared to conventional ones. When the acoustic path of transmitting room is changed, stereo AEC using proposed algorithm is well performed.

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Performance Improvement of Stereo Acoustic Echo Canceller Using MINT Filtering (MINT 필터링에 의한 스테레오 음향 반향 제거기의 성능 향상)

  • 차경환
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.1
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    • pp.42-46
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    • 2002
  • In this paper, a new pre-processing algorithm is proposed to improve the performance of stereo acoustic echo canceller. The proposed algorithm has the improved performance by the estimation error reduction of filter coefficient using input signal which was reduced reverberation of room in the basis MINT (Mu1tip1e-input/output Inverse Theorem) filtering. For real stereo speech signal and real room impulse response the results of simulation, we showed that the proposed method could improved 3∼5 dB ERLE (Echo Return Loss Enhancement) regardless of NLMS (Normalized Least Mean Square) and Projection adaptive algorithm.

Performance Improvement of Stereophonic Acoustic Echo Canceler Using Non-linear Pre-processing Filter (비선형 전처리필터를 이용한 스테레오 음향 반향 제거기의 성능향상)

  • 박장식;정일규;손경식;김현태
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.3
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    • pp.264-273
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    • 2002
  • Adaptive filters cannot exactly estimate the echo path of the receiving room because of the cross-correlation of stereo signals. In this paper, a new pre-processing method reducing the cross-correlation without degradation of stereophony is proposed to enhance the performance of stereophonic acoustic echo canceller. To reduce the cross-correlation, absolutes of two orthogonal signals derived from each channel signals are added to original channel signals. Assuming that the power of each channel signal is larger than that of the cross-correlation, the computation of pre-processing can be reduced. As results of simulations, it is shown that the performance of stereo acoustic echo canceller with the proposed pre-processing method is better than that of conventional ones.

Acoustic Echo Canceller for Synthetic Stereo Using HRTF (머리 전달 함수를 이용한 합성 스테레오 음향 반향 제거기)

  • 박장식;백주순;손경식
    • Proceedings of the Korea Multimedia Society Conference
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    • 2002.05c
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    • pp.149-153
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    • 2002
  • In this brief, Acoustic echo cancellation scheme is proposed to enhance the presence of multiple participants of hands-free voice and video conference. Synthetic stereo using head related transfer function and the stereo echo cancellation scheme are proposed. It is shown that the proposed synthetic stereo echo cancellation scheme is well performed by computer simulation.

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A Simplified Orthogonal Projection Algorithm for Stereo Acoustic Echo Cancellation (스테레오 음향반향제거를 위한 간략화된 직교투사 알고리즘)

  • Lee, Haeng-Woo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.11
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    • pp.2388-2396
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    • 2012
  • This paper is on an simplified orthogonal projection method which cancel the acoustic echo signals in the stereo acoustic echo canceller. Comparing with the NLMS algorithm which is widely used for simplicity and stability, it shows that this method has the improvement of the convergence performances for signals with the high auto-correlation, and has small computational quantities. To verify the convergence characteristics of the proposed algorithm, we simulated about various input signals. And we compared the results of simulation for this algorithm with the ones for the NLMS algorithm. By these works, it was proved that the stereo acoustic echo canceller adopting the proposed algorithm shows about 3dB more high ERLE than the NLMS algorithm for the white noise signals, and 5dB for the colored voice signals.

Stereo Acoustic Echo Canceller Using Difference Components of Channel Signals (채널 신호의 차성분을 이용한 스테레오 음향 반향 제거기)

  • Kim Hyun Tae;Park Jang Sik;Son Kyung Sik
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.119-122
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    • 1999
  • In stereo acoustic echo canceller scheme, adaptive filters coefficients converge very slowly or misconverge to real acoustic echo path in receiving room. This is due to cross-correlation between channel signals. In this paper, new preprocessor using absolute difference factor between stereo signals is proposed to reduce cross-correlation between signals. Computer simulations demonstrate that this preprocessor perform well to the half wave rectifier which has simple and good performance of the several preprocessors in recent papers. When the paths in transmitting room change, performance does not degrade in proposed preprocessor.

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Stereo Echo Canceller Using Non-linear Pre-processing Filter (비선형 전처리 필터를 이용한 스테레오 음향반향 제거기)

  • 정일규;김현태;박장식;손경식
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.193-196
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    • 2000
  • An stereophonic acoustic echo canceller cannot exactly estimate the echo path in the receiving room, because of the cross-correlation between stereo signals. In this paper, the new preprocessing filter is proposed to reduce the cross-correlation between the signals without influence on stereophonic sound. Two channel signals are linearly decorrelated by using orthogonality principles and the attenuated absolute values of the decorrelated signals are added to each channel input signals. Assuming that the power of each channel signal is larger than that of the cross-correlation, computational burden is reduced.

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