Midfrequency enhancement of the backscattering of tone bursts by thin spherical shells

Zhang, L. G.; Sun, Nai–Hsiang; Marston, Philip L.

doi:10.1121/1.403716

Cited by 42 publications

(28 citation statements)

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“…19 However, when the phase velocity c p is subsonic, the Lamb wave is launched on the cylinder in a different way. 15,19,25 In this case, the coupling and propagation of the subsonic Lamb wave can be illustrated geometrically as shown in Fig. 3(b).…”

Section: Results and Ray Interpretationmentioning

confidence: 97%

“…19 Then, the wave is modeled as if it transits instantaneously from point A to point A 0 and it circumnavigates with group velocity c g from point A 0 to point B 0 . 25 Then, it is modeled as if it transits instantaneously from point B 0 to point B and is reradiated to the receiver. Because the speed of the a 0 Lamb wave is faster than the a À 0 Lamb wave, wavefront B in Fig.…”

Section: Results and Ray Interpretationmentioning

confidence: 99%

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Acoustic quasi-holographic images of scattering by vertical cylinders from one-dimensional bistatic scans

Baik

Dudley

Marston

2011

The Journal of the Acoustical Society of America

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When synthetic aperture sonar (SAS) is used to image elastic targets in water, subtle features can be present in the images associated with the dynamical response of the target being viewed. In an effort to improve the understanding of such responses, as well as to explore alternative image processing methods, a laboratory-based system was developed in which targets were illuminated by a transient acoustic source, and bistatic responses were recorded by scanning a hydrophone along a rail system. Images were constructed using a relatively conventional bistatic SAS algorithm and were compared with images based on supersonic holography. The holographic method is a simplification of one previously used to view the time evolution of a target's response [Hefner and Marston, ARLO 2, 55-60 (2001)]. In the holographic method, the space-time evolution of the scattering was used to construct a two-dimensional image with cross range and time as coordinates. Various features for vertically hung cylindrical targets were interpreted using high frequency ray theory. This includes contributions from guided surface elastic waves, as well as transmitted-wave features and specular reflection.

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Section: Results and Ray Interpretationmentioning

confidence: 97%

Section: Results and Ray Interpretationmentioning

confidence: 99%

Acoustic quasi-holographic images of scattering by vertical cylinders from one-dimensional bistatic scans

Baik

Dudley

Marston

2011

The Journal of the Acoustical Society of America

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“…4,5,14 The main contribution of this article is to quantify the dependence of the time-frequency shifts of the MFE on the bistatic receiver angles and explain the observed timefrequency shifts using a previously derived quantitative ray theory for spherical shell's scattering. 11 Additionally, the advantage of an optimal array beamformer based on joint time delays and frequency shifts of the bistatic MFE arrival is illustrated for enhancing the bistatic detection of the MFE for spherical shells when compared to a traditional timedelay beamformer.…”

Section: Introductionmentioning

confidence: 99%

“…2). 7,9,11 For instance, the frequency band over which the MFE occurs is indicative of the shell material, and the temporal spacing between successive circumnavigating Lamb waves allows an estimate of the radius of the spherical shell 12 as well as the shell material properties. 13,14 Most time-frequency analysis of the MFE has focused on source-receiver configuration closed to monostatic where the MFE is most energetic, when source and receiver are close in azimuth with respect to the shell's centroid.…”

Section: Introductionmentioning

confidence: 99%

Time-frequency analysis of the bistatic acoustic scattering from a spherical elastic shell

Anderson

Sabra

Zakharia

et al. 2012

The Journal of the Acoustical Society of America

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The development of low-frequency sonar systems, using, for instance, a network of autonomous systems in unmanned vehicles, provides a practical means for bistatic measurements (i.e., when the source and receiver are widely separated) allowing for multiple viewpoints of the target of interest. Time-frequency analysis, in particular, Wigner-Ville analysis, takes advantage of the evolution time dependent aspect of the echo spectrum to differentiate a man-made target, such as an elastic spherical shell, from a natural object of the similar shape. A key energetic feature of fluid-loaded and thin spherical shell is the coincidence pattern, also referred to as the mid-frequency enhancement (MFE), that results from antisymmetric Lamb-waves propagating around the circumference of the shell. This article investigates numerically the bistatic variations of the MFE with respect to the monostatic configuration using the Wigner-Ville analysis. The observed time-frequency shifts of the MFE are modeled using a previously derived quantitative ray theory by Zhang et al. [J. Acoust. Soc. Am. 91, 1862-1874 (1993)] for spherical shell's scattering. Additionally, the advantage of an optimal array beamformer, based on joint time delays and frequency shifts is illustrated for enhancing the detection of the MFE recorded across a bistatic receiver array when compared to a conventional time-delay beamformer.

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“…However there are complicating factors to this simple approach: the speed of the Lamb wave, the distance the Lamb wave travels along the shell, and the arrival of (Zhang et al, 1992), this average value has been used previously with good results and wil be used in this analysis.…”

Section: Elastic-shelled Animalsmentioning

confidence: 99%

Estimating Gulf of Maine zooplankton distributions using multiple frequency acoustic, video and environmental data

Warren¹

2001

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This thesis develops methods useful for estimating zooplankton distributions in the field by combining acoustic models and an integrated set of field data. The accnracy of existing models for fluid-like and elastic-shelled animals is determined by analysis of scattering data from individual aninials in a laboratory tank. Results indicate that simple two-ray scattering rnodels are accurate and allow predictions of size or orientation of an animal to be made for certain animal orientations. A model for gas-bearing zooplankton is compared with in sit'l multiple frequency acoustic measurements from siphonophores. Estimates of the numerical density of these animals are made using echo integration data from a scientific echo-sounder. Multiple frequency acoustic scattering data from a survey of an internal wave are analyzed to determine the contributions from biologieal and physical sources. Net tow data provide information about biological scatterers while temperature and salinity profiles are used with a theoretical model to predict contributions from physical sources. Results indicate that scattering from physical sources is comparable to that from biological sources in certain regions and that spectra may be used to distinguish these sources. Improved estimates of biomass from acoustic scatteriug data were made by accounting for the scattering contributions from physical sources. This is the first work to quantify the scattering contributions from biological and physical sources of scattering in a field study. It is better to fail in originality than to succeed in iniitation. He who has never failed somewhere, that man cannot be great. If it be said that continual snccess is proof that a man wisely knows his powers, it is only to be added that, in that ease, he knows them to be smaIL Hennan MelvilleDon't believe the hype. That ¡nade the school a place of decent order vVhere books were read and sums were proven true And paper maps t.hat showed t.he land and water vVere held up as the real wide world to you. Always, he kept his eyes upon his books:And now he has grown to be a man fellow .II' classmates are an exceptional group of people, not to mention they're all wicked srnart.From the initial pot-lucks to the defense parties, it's been a fantastic group of people t.o have as my peers.Ann P. was always up for a "date". Liz K. survived 10 hours in a ear with me and didn't have to be institutionalized. Sheri \V. never tackled me too hard while playing rugby. Brenda J. attended Lollapalooza 5 with me. Nicole P. survived with me during our thesis writing. i'ike A. reminded me you're never too old to have fun. 'rom i'd., Lou StL., and l'like B. were the original members of VomeletLe. Suzie \V.enthusiasm for school was a contrast to mine. Fellow NRQ members ,Albert and i'ak, made the last 6 months of school very survivable. Doc Reddy made the best brunclics I've ever eaten, taught me many acronyms, was a co-founder of PNF and rescued me after my kayak was attacked a rogue buoy.

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Midfrequency enhancement of the backscattering of tone bursts by thin spherical shells

Cited by 42 publications

References 1 publication

Acoustic quasi-holographic images of scattering by vertical cylinders from one-dimensional bistatic scans

Acoustic quasi-holographic images of scattering by vertical cylinders from one-dimensional bistatic scans

Time-frequency analysis of the bistatic acoustic scattering from a spherical elastic shell

Estimating Gulf of Maine zooplankton distributions using multiple frequency acoustic, video and environmental data

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