Detecting acoustic transients by signal-to-noise ratio (SNR) becomes problematic in nonstationary ambient noise environments characteristic of coral reefs. An alternate approach presented here uses signal directionality to automatically detect and localize transient impulsive sounds collected on underwater vector sensors spaced tens of meters apart. The procedure, which does not require precise time synchronization, first constructs time-frequency representations of both the squared acoustic pressure (spectrogram) and dominant directionality of the active intensity (azigram) on each sensor. Within each azigram, sets of time-frequency cells associated with transient energy arriving from a consistent azimuthal sector are identified. Binary image processing techniques then link sets that share similar duration and bandwidth between different sensors, after which the algorithm triangulates the source location. Unlike most passive acoustic detectors, the threshold criterion for this algorithm is bandwidth instead of pressure magnitude. Data collected from shallow coral reef environments demonstrate the algorithm's ability to detect SCUBA bubble plumes and consistent spatial distributions of somniferous fish activity. Analytical estimates and direct evaluations both yield false transient localization rates from 3% to 6% in a coral reef environment. The SNR distribution of localized pulses off Hawaii has a median of 7.7 dB and interquartile range of 7.1 dB.
References
1.
Bertucci
, F.
, Parmentier
, E.
, Lecellier
, G.
, Hawkins
, A. D.
, and Lecchini
, D.
(2016
). “ Acoustic indices provide information on the status of coral reefs: An example from Moorea Island in the South Pacific
,” Scientific Reports
6
, 33326
.2.
Blackwell
, S. B.
, Nations
, C. S.
, McDonald
, T. L.
, Thode
, A. M.
, Mathias
, D.
, Kim
, K. H.
, Greene
, C. R.
, Jr. , and Macrander
, A. M.
(2015
). “ The effects of airgun sounds on bowhead whale calling rates: Evidence for two behavioral thresholds
,” PLoS One
10
, e0125720
.3.
Brown
, B.
(1997
). “ Coral bleaching: Causes and consequences
,” Coral Reefs
16
, 129
–138
..4.
Cray
, B. A.
, and Nuttall
, A. H.
(2001
). “ Directivity factors for linear arrays of velocity sensors
,” J. Acoust. Soc. Am.
110
, 324
–331
.5.
D'Spain
, G. L.
, Hodgkiss
, W. S.
, and Edmonds
, G. L.
(1991
). “ Energetics of the deep ocean's infrasonic sound field
,” J. Acoust. Soc. Am.
89
, 1134
–1158
.6.
D'Spain
, G. L.
, Luby
, J. C.
, Wilson
, G. R.
, and Gramann
, R. A.
(2006
). “ Vector sensors and vector sensor line arrays: Comments on optimal array gain and detection
,” J. Acoust. Soc. Am.
120
, 171
–185
.7.
Dahl
, P. H.
, and Dall'Osto
, D. R.
(2020
). “ Estimation of seabed properties and range from vector acoustic observations of underwater ship noise
,” J. Acoust. Soc. Am.
147
, EL345
–EL350
.8.
Deal
, T. J.
(2018
). “ Vector sensor cross-spectral density for surface noise in a stratified ocean—Formulas for arbitrary sensor geometries
,” J. Acoust. Soc. Am.
143
, 605
–615
.9.
Edwards
, C. B.
, Eynaud
, Y.
, Williams
, G. J.
, Pedersen
, N. E.
, Zgliczynski
, B. J.
, Gleason
, A. C.
, Smith
, J. E.
, and Sandin
, S. A.
(2017
). “ Large-area imaging reveals biologically driven non-random spatial patterns of corals at a remote reef
,” Coral Reefs
36
, 1291
–1305
.10.
Freeman
, S. E.
, Rohwer
, F. L.
, D'Spain
, G. L.
, Friedlander
, A. M.
, Gregg
, A. K.
, Sandin
, S. A.
, and Buckingham
, M. J.
(2014
). “ The origins of ambient biological sound from coral reef ecosystems in the Line Islands archipelago
,” J. Acoust. Soc. Am.
135
: 1775
–1788
.11.
Freeman
, L. A.
, and Freeman
, S. E.
(1993
). “ Rapidly obtained ecological indicators in coral reef soundscapes
,” Mar Ecol Prog Ser.
501
, 69
–82
.12.
Gillespie
, D.
, Mellinger
, D.
, Gordon
, J.
, Mclaren
, D.
, Redmond
, P.
, McHugh
, R.
, Trinder
, P.
, Deng
, X.
, and Thode
, A.
(2008
). “ PAMGUARD: Semiautomated, open source software for real-time acoustic detection and localisation of cetaceans
,” J. Acoust. Soc. Am.
30
, 54
–62
.13.
Glynn
, P. W.
(1993
). “ Coral Reef Bleaching: Ecological
,” Perspectives - Coral Reefs
12
, 1
–17
.14.
Gonzalez
, R.
, and Woods
, R.
(2002
). Digital Image Processing
(Prentice-Hall
, Upper Saddle River, NJ
).15.
Gordon
, T. A.
, Radford
, A. N.
, Davidson
, I. K.
, Barnes
, K.
, McCloskey
, K.
, Nedelec
, S. L.
, Meekan
, M. G.
, McCormick
, M. I.
, and Simpson
, S. D.
(2019
). “ Acoustic enrichment can enhance fish community development on degraded coral reef habitat
,” Nature Commun.
10
(1
), 1
–7
.16.
Gordon
, T. A.
(2020
). “ The changing song of the sea: Soundscapes as indicators and drivers of ecosystem transition on tropical coral reefs
,” Ph.D. thesis, University of Exeter.17.
Gracias
, N. R.
, van der Zwaan
, S.
, Bernardino
, A.
, and Santos-Victor
, J.
(2003
). “ Mosaic-based navigation for autonomous underwater vehicles
,” IEEE J. Oceanic Eng.
28
, 609
–624
.18.
Greene
, C. R.
, McLennan
, M. W.
, Norman
, R. G.
, McDonald
, T. L.
, Jakubczak
, R. S.
, and Richardson
, W. J.
(2004
). “ Directional frequency and recording (DIFAR) sensors in seafloor recorders to locate calling bowhead whales during their fall migration
,” J. Acoust. Soc. Am.
116
, 799
–813
.19.
Hawkes
, M.
, and Nehorai
, A.
(2003
). “ Wideband source localization using a distributed acoustic vector-sensor array
,” IEEE Trans. Signal Process.
51
, 1479
–1491
.20.
Holler
, R. A.
(2014
). “ The evolution of the sonobuoy from World War II to the Cold War
,” U.S. Navy J. Underwater Acoust.
62
, 322
–347
.21.
Johannes
, R. E.
(1981
). Words of the Lagoon: Fishing and Marine Lore in the Palau District of Micronesia
(University of California Press
, Los Angeles, CA
).22.
Kennedy
, E. V.
, Holderied
, M. W.
, Mair
, J. M.
, Guzman
, H. M.
, and Simpson
, S. D.
(2010
). “ Spatial patterns in reef-generated noise relate to habitats and communities: Evidence from a Panamanian case study
,” J. Exp Mar Biol Ecol.
395
(1
), 85
–92
.23.
Kleypas
, J. A.
, and Yates
, K. K.
(2009
). “ Coral reefs and ocean acidification
,” Oceanography
22
, 4
.24.
Lenth
, R. V.
(1981
). “ On finding the source of a signal
,” Technometrics
23
, 149
–154
.25.
Lieske
, E.
, and Myers
, R.
(2002
). Coral Reef Fishes: Dynamics and Diversity in a Complex Ecosystem
(Academic Press
, New York
).26.
Lilly
, J. M.
, and Olhede
, S. C.
(2012
). “ Generalized Morse wavelets as a superfamily of analytic wavelets
,” IEEE Trans. Signal Process.
60
, 6036
–6041
.27.
Lirman
, D.
, Gracias
, N. R.
, Gintert
, B. E.
, Gleason
, A. C. R.
, Reid
, R. P.
, Negahdaripour
, S.
, and Kramer
, P.
(2007
). “ Development and application of a video-mosaic survey technology to document the status of coral reef communities
,” Environ. Monitor. Assess.
125
, 59
–73
.28.
Mardia
, K. V.
, and Jupp
, P. E.
(2009
). Directional Statistics
(John Wiley & Sons
, New York
).29.
McWilliam
, J. N.
, McCauley
, R. D.
, Erbe
, C.
, and Parsons
, M. J.
(2017
). “ Patterns of biophonic periodicity on coral reefs in the Great Barrier Reef
,” Scientific Reports
7
(1
), 1
–13
.30.
Mellinger
, D. K.
, and Clark
, C. W.
(2000
). “ Recognizing transient low-frequency whale sounds by spectrogram correlation
,” J. Acoust. Soc. Am.
107
, 3518
–3529
.31.
Nehorai
, A.
, and Paldi
, E.
(1994
). “ Vector-sensor array processing for electromagnetic source localization
,” IEEE Trans. Signal Process.
42
, 376
–398
.32.
Nitzberg
, R.
(1986
). “ Clutter Map CFAR Analysis
,” IEEE Trans. Aerospace and Electronic Systems
AES-22
, 419
- 421
.33.
Pandolfi
, J. M.
, Jackson
, J. B. C.
, Baron
, N.
, Bradbury
, R. H.
, Guzman
, H. M.
, and Hughes
, T. P.
(2005
). “ Are US coral reefs on the slippery slope to slime?
” Science
307
(5716
), 1725
–1726
.34.
Preskitt
, L. V.
, Vroom
, P. S.
, and Smith
, C. M.
, “ A rapid ecological assessment (REA) quantitative survey method for benthic algae using photoquadrats with SCUBA
,” (2004
). Pacific Science
58
, 201
–209
.35.
Putland
, R.
, Mackiewicz
, A.
, and Mensinger
, A.
(2018
). “ Localizing individual soniferous fish using passive acoustic monitoring
,” Ecolog. Inf.
48
, 60
–68
.36.
Shi
, J.
, Dosso
, S. E.
, Sun
, D.
, and Liu
, Q.
(2019
). “ Geoacoustic inversion of the acoustic-pressure vertical phase gradient from a single vector sensor
,” J. Acoust. Soc. Am.
146
, 3159
–3173
.37.
Shipps
, J. C.
, and Deng
, K.
(2003
). “ A miniature vector sensor for line array applications
,” in Proceedings of IEEE Oceans
, September 22–26, San Diego, CA, pp. 2367
–2370
.38.
Thode
, A.
, Skinner
, J.
, Scott
, P.
, Roswell
, J.
, Straley
, J.
, and Folkert
, K.
(2010
). “ Tracking sperm whales with a towed acoustic vector sensor
,” J. Acoust. Soc. Am.
128
, 2681
–2694
.39.
Thode
, A. M.
, Blackwell
, S. B.
, Conrad
, A. S.
, Kim
, K. H.
, Marques
, T.
, Thomas
, L.
, Oedekoven
, C. S.
, Harris
, D.
, and Bröker
, K.
(2020
). “ Roaring and repetition: How bowhead whales adjust their call density and source level (Lombard effect) in the presence of natural and seismic airgun survey noise
,” J. Acoust. Soc. Am.
147
, 2061
–2080
.40.
Thode
, A. M.
, Kim
, K. H.
, Blackwell
, S. B.
, Greene
, C. R.
, and Macrander
, M. A.
(2012
). “ Automated detection and localization of bowhead whale sounds in the presence of seismic airgun surveys
,” J. Acoust. Soc. Am.
131
, 3726
–3747
.41.
Thode
, A. M.
, Kim
, K. H.
, Norman
, R. G.
, Blackwell
, S. B.
, and Greene
, C. R.
, Jr. (2016
). “ Acoustic vector sensor beamforming reduces masking from underwater industrial noise during passive monitoring
,” J. Acoust. Soc. Am.
139
, EL105
–EL111
.42.
Thode
, A. M.
, Sakai
, T.
, Michalec
, J.
, Rankin
, S.
, Soldevilla
, M. S.
, Martin
, B.
, and Kim
, K. H.
(2019
). “ Displaying bioacoustic directional information from sonobuoys using ‘azigrams
,’” J. Acoust. Soc. Am.
146
, 95
–102
.43.
Torrence
, C.
, and Compo
, G. P.
(1998
). “ A practical guide to wavelet analysis
,” Bull. Am. Meteorol. Soc.
79
, 61
–78
.44.
Tricas
, T. C.
, and Boyle
, K. S.
(2014
). “ Acoustic behaviors in Hawaiian coral reef fish communities
,” Mar. Ecol. Prog. Ser.
511
, 1
–16
.45.
Ullman
, S.
(1979
). “ The interpretation of structure from motion
,” Proc. R. Soc. Lond. Ser. B.
203
, 405
–426
.46.
Vermeij
, M. J.
, Marhaver
, K. L.
, Huijbers
, C. M.
, Nagelkerken
, I.
, and Simpson
, S. D.
(2010
). “ Coral larvae move toward reef sounds
,” PloS one
5
(5
), e10660
.47.
Wilcock
, W.
(2012
). “ Tracking fin whales in the northeast Pacific Ocean with a seafloor seismic network
,” J. Acoust. Soc. Am.
133
, 2503
–2503
.48.
Zimmer
, W. M. X.
(2011
). Passive Acoustic Monitoring of Cetaceans
(Cambridge University Press
, Cambridge, UK
).© 2021 Acoustical Society of America.
2021
Acoustical Society of America
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