The Physics of Sound in the Sea

Bergmann, Philipp; Spitzer, Lyman

doi:10.21236/ad0200624

Cited by 15 publications

(14 citation statements)

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“…from the Gamma distribution of W j in Equation (8). The variance of the MLE when J = M then attains the CRLB, since it equals the diagonal elements of the inverse of I from Equation (18):…”

Section: Statistics Of the Maximum Likelihood Estimatormentioning

confidence: 97%

“…We take advantage of the relatively pervasive circular complex Gaussian random (CCGR) statistics of acoustic fields in the ocean that follow from the central limit theorem for many typical scenarios of propagation, radiation or scattering [4][5][6][8][9][10][11][12][13][14]. Instantaneous intensity then follows a negative exponential distribution with a standard deviation proportional to the mean [9].…”

Section: Introductionmentioning

confidence: 99%

“…Instantaneous intensity then follows a negative exponential distribution with a standard deviation proportional to the mean [9]. This leads to intensity images that have inherent signal-dependent noise known as speckle [8,9,11,15], as well as possible independent additive noise in the CCGR fields. Given these statistics, the ML estimator is then derived to resolve the angular distribution of incident plane waves from coherent array measurements.…”

Section: Introductionmentioning

confidence: 99%

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Maximum Likelihood Deconvolution of Beamformed Images with Signal-Dependent Speckle Fluctuations from Gaussian Random Fields: With Application to Ocean Acoustic Waveguide Remote Sensing (OAWRS)

Jain

Makris

2016

Remote Sensing

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Abstract:Wide area acoustic remote sensing often involves the use of coherent receiver arrays to determine the spatial distribution of sources and scatterers at any instant. The resulting acoustic intensity images are typically corrupted by signal-dependent noise from Gaussian random field fluctuations arising from the central limit theorem and have a spatial resolution that depends on the incident direction, sensing array aperture and wavelength. Here, we use the maximum likelihood method to deconvolve the intensity distribution measured on a coherent line array assuming a discrete angular distribution of incident plane waves. Instantaneous wide area population density images of fish aggregations measured with Ocean Acoustic Waveguide Remote Sensing (OAWRS) are deconvolved to illustrate the effectiveness of this approach in improving angular resolution over conventional planewave beamforming.

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“…from the Gamma distribution of W j in Equation (8). The variance of the MLE when J = M then attains the CRLB, since it equals the diagonal elements of the inverse of I from Equation (18):…”

Section: Statistics Of the Maximum Likelihood Estimatormentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Maximum Likelihood Deconvolution of Beamformed Images with Signal-Dependent Speckle Fluctuations from Gaussian Random Fields: With Application to Ocean Acoustic Waveguide Remote Sensing (OAWRS)

Jain

Makris

2016

Remote Sensing

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“…2 Furthermore, for typical microlensing events within our galaxy, the technique is most sensitive for planets orbiting a few AU from their stars. Hence the fond hope that microlensing would soon discover Earth-like planets.…”

Section: Gravitational Microlensing Reveals the Lightest Exoplanet Yementioning

confidence: 99%

Acoustic-waveguide sonar finds enormous fish shoals

Wilson¹

2006

Physics Today

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“…In both deep ocean and shallow water continental shelf environments, a major source of acoustic field scintillation is internal waves [7,8,9]. Early efforts to describe signal scintillation statistics in the ocean were based on multipath theory, with the resultant field being the sum of multiple random phase components [10,11,12]. The instantaneous received signal therefore has an exponential distribution for intensity or a Rayleigh distribution for amplitude [10,11,12], and a 5.6 dB intensity standard deviation [11].…”

Section: Introductionmentioning

confidence: 99%

Probability distribution for energy of saturated broadband ocean acoustic transmission: Results from Gulf of Maine 2006 experiment

Tran¹,

Ratilal²

2013

Proceedings of Meetings on Acoustics

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The probability distribution of ocean-acoustic broadband signal energy after saturated multipath propagation is derived using coherence theory. The frequency components obtained from Fourier decomposition of a broadband signal are each assumed to be fully saturated with energy spectral density that obey the exponential distribution with 5.6 dB standard deviation and unity scintillation index. When the signal bandwidth and measurement time are larger than the correlation bandwidth and correlation time respectively of its energy spectral density components, the broadband signal energy obtained by integrating the energy spectral density across the signal bandwidth then follows the Gamma distribution with standard deviation smaller than 5.6 dB and scintillation index less than unity. The theory is verified with broadband transmissions in the Gulf of Maine shallow water waveguide in the 300-1200 Hz frequency range. The standard deviations of received broadband signal energies range from 2.7 to 4.6 dB for effective bandwidths up to 42 Hz, while the standard deviations of individual energy spectral density components are roughly 5.6 dB. The energy spectral density correlation bandwidths of the received broadband signals are found to be larger for signals with higher center frequencies and are roughly 10% of each center frequency.

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The Physics of Sound in the Sea

Cited by 15 publications

References 0 publications

Maximum Likelihood Deconvolution of Beamformed Images with Signal-Dependent Speckle Fluctuations from Gaussian Random Fields: With Application to Ocean Acoustic Waveguide Remote Sensing (OAWRS)

Maximum Likelihood Deconvolution of Beamformed Images with Signal-Dependent Speckle Fluctuations from Gaussian Random Fields: With Application to Ocean Acoustic Waveguide Remote Sensing (OAWRS)

Acoustic-waveguide sonar finds enormous fish shoals

Probability distribution for energy of saturated broadband ocean acoustic transmission: Results from Gulf of Maine 2006 experiment

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