Implementation of stereophonic acoustic echo canceller on nVIDIA GeForce graphics processing unit

金沢大学理工研究域電子情報学系This paper presents an implementation of a stereophonic acoustic echo canceller on nVIDIA GeForce graphics processor and CUDA software development environment. For ef.ciency, fast shared memory has been used as much as possilbe. A tree adder is introduced to reduce the cost for summing thread outputs up. The performance evaluation results suggest that Even a low-cost GPU\u27s with a small number of shader processor greatly helps the echo cancellation for low-cost PC-based teleconferencing. ©2009 IEEE.

Implementation of stereophonic acoustic echo canceller on nVIDIA GeForce graphics processing unit

金沢大学理工研究域電子情報学系This paper presents an implementation of a stereophonic acoustic echo canceller on nVIDIA GeForce graphics processor and CUDA software development environment. For ef.ciency, fast shared memory has been used as much as possilbe. A tree adder is introduced to reduce the cost for summing thread outputs up. The performance evaluation results suggest that Even a low-cost GPU\u27s with a small number of shader processor greatly helps the echo cancellation for low-cost PC-based teleconferencing. ©2009 IEEE.

Implementation of Stereophonic Acoustic Echo Canceller on Intel IA-32 Processors with SIMD Capability

金沢大学理工研究域　電子情報学系本論文では、ステレオ音響エコーキャンセラのIntel IA-32プロセッサによる効率的な実現方法を検討する。SIMD実現でしばしば遭遇するデータ配置問題を、データ領域の増大なしで解決している。スカラ演算による実現と比較して4倍以上の高速化を達成している

Stereo Acoustic Echo Control Using A Simplified Echo Path Model

In handsfree tele- or video-communication, acoustic echoes arise due to the coupling between the loudspeakers and microphones. It is much more challenging to remove the undesired acoustic echoes for stereo or multi-channel tele-communication systems than for mono systems due to the non-uniqueness problem. While non-uniqueness can be prevented by introducing independent distortions into the left and right loudspeaker signals, stereo echo cancellation is more challenging in terms of convergence speed and computational complexity than mono echo cancellation. The proposed stereo echo control algorithm circumvents the non-uniqueness problem by using simplified echo path models consisting of delays and short-time spectral modification. It is shown that for reasonably symmetric systems the left and right echo path models are similar enough that a single echo path model can be used for estimating the total echo power spectrum and a gain filter for removing the echo from the microphone channels. The proposed algorithm is also applicable to multi-channel systems and the computational complexity is very low

System approach to robust acoustic echo cancellation through semi-blind source separation based on independent component analysis

We live in a dynamic world full of noises and interferences. The conventional acoustic echo cancellation (AEC) framework based on the least mean square (LMS) algorithm by itself lacks the ability to handle many secondary signals that interfere with the adaptive filtering process, e.g., local speech and background noise. In this dissertation, we build a foundation for what we refer to as the system approach to signal enhancement as we focus on the AEC problem. We first propose the residual echo enhancement (REE) technique that utilizes the error recovery nonlinearity (ERN) to "enhances" the filter estimation error prior to the filter adaptation. The single-channel AEC problem can be viewed as a special case of semi-blind source separation (SBSS) where one of the source signals is partially known, i.e., the far-end microphone signal that generates the near-end acoustic echo. SBSS optimized via independent component analysis (ICA) leads to the system combination of the LMS algorithm with the ERN that allows for continuous and stable adaptation even during double talk. Second, we extend the system perspective to the decorrelation problem for AEC, where we show that the REE procedure can be applied effectively in a multi-channel AEC (MCAEC) setting to indirectly assist the recovery of lost AEC performance due to inter-channel correlation, known generally as the "non-uniqueness" problem. We develop a novel, computationally efficient technique of frequency-domain resampling (FDR) that effectively alleviates the non-uniqueness problem directly while introducing minimal distortion to signal quality and statistics. We also apply the system approach to the multi-delay filter (MDF) that suffers from the inter-block correlation problem. Finally, we generalize the MCAEC problem in the SBSS framework and discuss many issues related to the implementation of an SBSS system. We propose a constrained batch-online implementation of SBSS that stabilizes the convergence behavior even in the worst case scenario of a single far-end talker along with the non-uniqueness condition on the far-end mixing system. The proposed techniques are developed from a pragmatic standpoint, motivated by real-world problems in acoustic and audio signal processing. Generalization of the orthogonality principle to the system level of an AEC problem allows us to relate AEC to source separation that seeks to maximize the independence, hence implicitly the orthogonality, not only between the error signal and the far-end signal, but rather, among all signals involved. The system approach, for which the REE paradigm is just one realization, enables the encompassing of many traditional signal enhancement techniques in analytically consistent yet practically effective manner for solving the enhancement problem in a very noisy and disruptive acoustic mixing environment.PhDCommittee Chair: Biing-Hwang Juang; Committee Member: Brani Vidakovic; Committee Member: David V. Anderson; Committee Member: Jeff S. Shamma; Committee Member: Xiaoli M