Sub-Nyquist spatial sampling using arrays of directional microphones

Microphone arrays are commonly used for spatial filtering or beamforming. A variety of beamforming techniques offering high spatial resolution have been developed and are described in the literature. However, improved resolution may require an increase in the number of sensors and channels, resulting in complicated and expensive systems. In the current paper the use of arrays composed of directional sensors is proposed and the consequent benefit in terms of a reduction in the number of sensors is analyzed. It is shown that a reduction in the number of sensors can be achieved at the expense of reduced steering capabilities.

[1]  Yang-Ho Choi.  Simple adaptive beamforming with only real weights based on covariance differencing , 2007 .

[2]  E. Williams,et al.  Fourier Acoustics: Sound Radiation and Nearfield Acoustical Holography , 1999 .

[3]  J. Ealo,et al.  Airborne ultrasonic phased arrays using ferroelectrets: a new fabrication approach , 2009, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[4]  D. I. Havelock.  Residual noise in the aggregate beamformer , 2003, 2003 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (IEEE Cat. No.03TH8684).

[5]  J. Griffiths.  Adaptive array processing. A tutorial , 1983 .

[6]  Jens Meyer,et al.  Spherical Microphone Array for Spatial Sound Recording , 2002 .

[7]  Boaz Rafaely,et al.  Electronic steering for a microphone array by sub-band phase compensation , 2010, 2010 IEEE 26-th Convention of Electrical and Electronics Engineers in Israel.

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

[9]  Harry L. Van Trees,et al.  Optimum Array Processing , 2002 .

[10]  J.L. Ealo,et al.  Broadband EMFi-based transducers for ultrasonic air applications , 2008, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[11]  Boaz Rafaely,et al.  Analysis and design of spherical microphone arrays , 2005, IEEE Transactions on Speech and Audio Processing.

[12]  F. Seco,et al.  Customizable field airborne ultrasonic transducers based on electromechanical film , 2008, 2008 IEEE Ultrasonics Symposium.

[13]  Mohammad Ghavami.  Wideband beamforming using rectangular arrays without phase shifting , 2003, Eur. Trans. Telecommun..

[14]  M. Paajanen,et al.  EMFi-New electret material for sensors and actuators , 1999, 10th International Symposium on Electrets (ISE 10). Proceedings (Cat. No.99 CH36256).

[15]  W. Marsden.  I and J , 2012 .

[16]  Boaz Rafaely,et al.  Maximum directivity beamformer for spherical-aperture microphones , 2009, 2009 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics.

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

[18]  Jukka Lekkala,et al.  ElectroMechanical Film (EMFi) — a new multipurpose electret material , 2000 .

[19]  M. Viberg,et al.  Two decades of array signal processing research: the parametric approach , 1996, IEEE Signal Process. Mag..

[20]  David I Havelock.  Sensor array beamforming using random channel sampling: the aggregate beamformer. , 2003, The Journal of the Acoustical Society of America.