Herein investigated are computationally simple microphone-array beamformers that are independent of the frequency-spectra of all signals, all interference, and all noises. These beamformers allow the listener to tune the desired azimuth-elevation “look direction.” No prior information is needed of the interference. These beamformers deploy a physically compact triad of three collocated but orthogonally oriented velocity sensors. These proposed schemes’ efficacy is verified by a jury test, using simulated data constructed with Mandarin Chinese (a.k.a. Putonghua) speech samples. For example, a desired speech signal, originally at a very adverse signal-to-interference-and-noise power ratio (SINR) of −30 dB, may be processed to become fully intelligible to the jury.
REFERENCES
1.
Such beamforming may be construed as a spatial counterpart of a passband-stopband frequency filter. Instead of the latter’s discrete-time samples, a beamformer collects spatial samples visa multiple sensors distributed over a spatial region.
2.
When any emitter lies in the acoustic vector-sensor’s near field, the pressure-sensor’s response will be frequency-dependent (Ref. 5). Hence, the present beamformer will omit the pressure sensor to maintain the beamformer’s frequency independence for all near-field/far-field sources.
3.
A.
Nehorai
and E.
Paldi
, “Acoustic vector-sensor array processing
,” IEEE Trans. Signal Process.
42
, 2481
–2491
(1994
).4.
J. A.
McConnell
, “Analysis of a compliantly suspended acoustic velocity sensor
,” J. Acoust. Soc. Am.
113
, 1395
–1405
(2003
).5.
Y. I.
Wu
, K. T.
Wong
, and S. K.
Lau
, “The acoustic vector-sensor’s near-field array-manifold
,” IEEE Trans. Signal Process.
58
, 3946
–3951
(2010
).6.
B.
Hochwald
and A.
Nehorai
, “Identifiability in array processing models with vector-sensor applications
,” IEEE Trans. Signal Process.
44
, 83
–95
(1996
).7.
M.
Hawkes
and A.
Nehorai
, “Effects of sensor placement on acoustic vector-sensor array performance
,” IEEE J. Ocean. Eng.
24
, 33
–40
(1999
).8.
B. A.
Cray
and A. H.
Nuttall
, “Directivity factors for linear arrays of velocity sensors
,” J. Acoust. Soc. Am.
110
, 324
–331
(2001
).9.
K. T.
Wong
and H.
Chi
, “Beam patterns of an underwater acoustic vector hydrophone located away from any reflecting boundary
,” IEEE J. Ocean. Eng.
27
, 628
–637
(2002
).10.
M. T.
Silvia
and R. T.
Richards
, “A theoretical and experimental investigation of low-frequency acoustic vector sensors
,” in IEEE Oceans Conference
(2002
), pp. 1886
–1897
.11.
B. A.
Cray
, “Directional point receivers: The sound and the theory
,” in IEEE Oceans Conference
(2002
), pp. 1903
–1905
.12.
B. R.
Rapids
and G. C.
Lauchle
, “Processing of forward scattered acoustic fields with intensity sensors
,” in IEEE Oceans Conference
(2002
), pp. 1911
–1914
.13.
B. A.
Cray
, V. M.
Evora
, and A. H.
Nuttall
, “Highly directional acoustic receivers
,” J. Acoust. Soc. Am.
113
, 1527
–1533
(2003
).14.
S.
Guiqing
, L.
Qihu
, and Z.
Bin
, “Acoustic vector sensor signal processing
,” Chin. J. Acoust.
25
, 1
–14
(2006
).15.
H.
Cox
, “Super-directivity revisited
,” in IEEE Instrumentation and Measurement Technology Conference
(2004
), pp. 87
–90
.16.
H.
Keshavarz
, “Beam patterns of an underwater acoustic vector hydrophone located near a reflecting boundary
,” in IEEE Oceans Conference
(2004
), Vol. 2
, pp. 585
–588
.17.
G. L.
D’Spain
, J. C.
Luby
, G. R.
Wilson
, and R. A.
Gramann
, “Vector sensors and vector sensor line arrays: Comments on optimal array gain and detection
,” J. Acoust. Soc. Am.
120
, 171
–185
(2006
).18.
N.
Qi
and T.
Tian
, “Acoustic vector hydrophone array supergain energy flux beamforming
,” in International Conference on Signal Processing
(2006
), Vol. 4
.19.
D. J.
Schmidlin
, “Directionality of generalized acoustic sensors of arbitrary order
,” J. Acoust. Soc. Am.
121
, 3569
–3578
(2007
).20.
H.
Cox
and H.
Lai
, “Performance of line arrays of vector and higher order sensors
,” in Asilomar Conference on Signals, Systems and Computers
(2007
), pp. 1231
–1236
.21.
J. A.
Clark
, “High-order angular response beamformer for vector sensors
,” J. Sound Vib.
318
(3
), 417
–422
(2008
).22.
P. K.
Tam
and K. T.
Wong
, “Cramer-rao bounds for direction finding by an acoustic vector sensor under nonideal gain-phase responses, noncollocation, or nonorthogonal orientation
,” IEEE Sens. J.
9
, 969
–982
(2009
).23.
K. T.
Wong
, “Acoustic vector-sensor ffh blind beamforming & geolocation
,” IEEE Trans. Aerosp. Electron. Syst.
46
, 444
–449
(2010
).24.
Y. I.
Wu
and K. T.
Wong
, “Acoustic near-field source localization by two passive anchor nodes
,” IEEE Trans. Aerosp. Electron. Syst.
48
, 159
–169
(2012
).25.
H.
Cox
and R. M.
Zeskind
, “Adaptive cardiod processing
,” in Asilomar Conference on Signals, Systems and Computers
(1992
), pp. 1058
–1061
.26.
M.
Hawkes
and A.
Nehorai
, “Acoustic vector-sensor beamforming and capon direction estimation
,” IEEE Trans. Signal Process.
46
, 2291
–2304
(1998
).27.
H.
Junying
, L.
Chunxu
, L.
Guolong
, and L.
Hong
, “A combined signal processing approach against coherent interference with pressure and particle velocity
,” Chin. J. Acoust.
20
, 2001
–2010
(2001
).28.
J.
Hui
, H.
Liu
, M.
Fan
, and G.
Liang
, “Study on the physical basis of pressure and particle velocity combine processing
,” Chin. J. Acoust.
20
, 203
–212
(2001
).29.
H. W.
Chen
and J. W.
Zhao
, “Wideband mvdr beamforming for acoustic vector sensor linear array
,” IEE Proc., Radar Sonar Navig.
151
, 158
–162
(2004
).30.
S.
Guiqing
and L.
Qihu
, “Acoustic vector sensor signal processing
,” Acta Acust.
29
, 491
–498
(2004
).31.
M. E.
Lockwood
and D. L.
Jones
, “Beamformer performance with acoustic vector sensors in air
,” J. Acoust. Soc. Am.
119
, 608
–619
(2006
).32.
H.
Cox
and H.
Lai
, “Endfire supergain with a uniform line array of pressure and velocity sensors
,” in Asilomar Conference on Signals, Systems and Computers
(2006
), pp. 2271
–2275
.33.
H.
Lai
, H.
Cox
, and K.
Bell
, “Adaptive factored beamforming for vector sensor arrays
,” in Asilomar Conference on Signals, Systems and Computers
(2008
), pp. 402
–406
.34.
A.
Agarwal
, A.
Kumar
, M.
Aggarwal
, and R.
Bahl
, “Design and experimentation with acoustic vector sensors
,” in International Symposium on Ocean Electronics
(2009
), pp. 139
–146
.35.
Please see equation (6.202) on page 491 of Ref. 38.
36.
D. G.
Manolakis
, Statistical and Adaptive Signal Processing: Spectral Estimation, Signal Modeling, Adaptive Filtering and Array Processing
, 641
–656
(McGraw-Hill
, Boston, MA
, 2000
).37.
H. L. V.
Trees
, Detection, Estimation, and Modulation Theory, Part IV: Optimum Array Processing
(Wiley
, New York
, 2002
), pp. 439
–512
.38.
H.
Cox
, “Resolving power and sensitivity to mismatch of optimum array processors
,” J. Acoust. Soc. Am.
54
, 771
–785
(1973
).39.
Please see equations (6.218) to (6.230) in Ref. 38.
40.
R. O.
Schmidt
, “Multiple emitter location and signal parameter estimation
,” IEEE Trans. Antennas Propag.
AP-34
, 276
–280
(1986
).41.
M.
Shujau
, C. H.
Ritz
, and I. S.
Burnett
, “Using in-air acoustic vector sensors for tracking moving speakers
,” in International Conference on Signal Processing and Communication Systems
(2010
), pp. 1
–5
.42.
J.
Li
, P.
Stoica
, and Z.
Wang
, “On robust capon beamforming and diagonal loading
,” IEEE Trans. Signal Process.
51
, 1702
–1715
(2003
).43.
Y.
Zhang
, D.
Sun
, and D.
Zhang
, “Robust adaptive acoustic vector sensor beamforming using automated diagonal loading
,” Appl. Acoust.
70
, 1029
–1033
(2009
).© 2012 Acoustical Society of America.
2012
Acoustical Society of America
You do not currently have access to this content.