Enhanced MVDR Beamforming for Arrays of Directional Microphones

Microphone arrays based on the minimum variance distortionless response (MVDR) beamformer are among the most popular for speech enhancement applications. The original MVDR is excessively sensitive to source location and microphone gains. Previous research has made MVDR practical by successfully increasing the robustness of MVDR to source location, and MVDR-based microphone arrays are already commercially available. Nevertheless, MVDR performance is still weak in cases where microphone gain variations are too large, e.g., for circular arrays of directional microphones. In this paper we propose an improved MVDR beamformer which takes into account the effect of sensors (e.g. microphones) with arbitrary, potentially directional responses. Specifically, we form estimates of the relative magnitude responses of the sensors based on the data received at the array and include those in the original formulation of the MVDR beamforming problem. Experimental results on real-world audio data show an average 2.4 dB improvement over conventional MVDR beamforming, which does not account for the magnitude responses of the sensors.

[1]  Anoop Gupta,et al.  Distributed meetings: a meeting capture and broadcasting system , 2002, MULTIMEDIA '02.

[2]  Hong Wang,et al.  Voice source localization for automatic camera pointing system in videoconferencing , 1997, Proceedings of 1997 Workshop on Applications of Signal Processing to Audio and Acoustics.

[3]  Henry Cox,et al.  Robust adaptive beamforming , 2005, IEEE Trans. Acoust. Speech Signal Process..

[4]  Sascha Spors,et al.  Joint audio-video object localization and tracking , 2001 .

[5]  Daniel Jackson Allred.  Evaluation and Comparison of Beamforming Algorithms for Microphone Array Speech Processing , 2006 .

[6]  Amr El-Keyi,et al.  Robust adaptive beamforming based on the Kalman filter , 2005, IEEE Transactions on Signal Processing.

[7]  Petre Stoica,et al.  Robust Adaptive Beamforming: Li/Robust Adaptive Beamforming , 2005 .

[8]  Henrique S. Malvar.  A modulated complex lapped transform and its applications to audio processing , 1999, 1999 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258).

[9]  P. Thushara D Abhayapala.  Modal Analysis and Synthesis of Broadband Nearfield Beamforming Arrays , 1999 .

[10]  Akihiko Sugiyama,et al.  A robust adaptive beamformer for microphone arrays with a blocking matrix using constrained adaptive filters , 1999, IEEE Trans. Signal Process..

[11]  Paul A. Viola,et al.  Boosting-Based Multimodal Speaker Detection for Distributed Meetings , 2006, 2006 IEEE Workshop on Multimedia Signal Processing.

[12]  Jeffrey L. Krolik,et al.  Relationships between adaptive minimum variance beamforming and optimal source localization , 2000, IEEE Trans. Signal Process..

[13]  L. J. Griffiths,et al.  An alternative approach to linearly constrained adaptive beamforming , 1982 .

[14]  Yong Rui,et al.  Time delay estimation in the presence of correlated noise and reverberation , 2004, 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[15]  Zhengyou Zhang,et al.  Maximum Likelihood Sound Source Localization for Multiple Directional Microphones , 2007, 2007 IEEE International Conference on Acoustics, Speech and Signal Processing - ICASSP '07.

[16]  B.D. Van Veen,et al.  Beamforming: a versatile approach to spatial filtering , 1988, IEEE ASSP Magazine.

[17]  Henrique S. Malvar,et al.  A new beamformer design algorithm for microphone arrays , 2005, Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005..