Imaging of passive targets in shallow‐water using an ambient noise acoustic imaging system.

1996 ◽  
Vol 99 (4) ◽  
pp. 2453-2457 ◽  
Author(s):  
Marc P. Olivieri ◽  
Stewart A. L. Glegg ◽  
Robert K. Coulson
Keyword(s):  
Shallow Water ◽  
Ambient Noise ◽  
Imaging System ◽  
Acoustic Imaging

THEORY OF ACOUSTIC IMAGING IN THE OCEAN WITH AMBIENT NOISE

1993 ◽  
Vol 01 (01) ◽  
pp. 117-140 ◽  
Author(s):  
MICHAEL J. BUCKINGHAM
Keyword(s):  
Ambient Noise ◽  
Imaging System ◽  
Sole Source ◽  
Acoustic Imaging ◽  
Accurate Approximation ◽  
Theoretic Analysis ◽  
Acoustic Lens ◽  
Full Wave ◽  
Line Array ◽  
Incoherent Imaging

Following a recent experiment in which ambient noise (acoustic daylight) was used as the sole source of acoustic illumination for detecting objects in the ocean, a full wave-theoretic analysis is presented in this article of the visibility of a pressure-release spherical target when illuminated by ambient noise showing various degrees of anisotropy. The basis of the analysis is a new, accurate approximation for the Green's function representing the field around the sphere. From this expression, an analysis of the acoustic contrast is developed, as observed at the output of an endfire line array, which constitutes the acoustic lens. Our essential conclusion is that, even in isotropic noise, which presents one of the least favourable conditions for incoherent imaging, the visibility of the sphere (i.e. the ratio of intensities with the sphere present and absent) is approximately 4 dB. This is consistent with our early experimental observations, and is adequate to form the basis of an acoustic daylight imaging system.

Acoustic Imaging with Ambient Noise: Theory and Simulation

2012 ◽  
Vol 457-458 ◽  
pp. 293-298
Author(s):  
Zhao Ran Meng ◽  
Ying Zi Wu
Keyword(s):  
High Resolution ◽  
Plane Wave ◽  
Point Source ◽  
Ambient Noise ◽  
Imaging System ◽  
Imaging Technique ◽  
Acoustic Imaging ◽  
Basic Theory

A new kind of acoustic imaging technique was discussed in this article. The basic theory of acoustic imaging was stated and some result of simulation including the images of point source and plane wave in the imaging system was shown. The result of simulation of point source and plane wave prove that it is feasible in certain range of acoustic imaging. In high frequent band, we can get a obvious contrast between source and background and high resolution.

Analysis and Modeling of Ambient Noise in Shallow Water of Arabian Sea

2012 ◽  
Vol 2 (6) ◽  
pp. 271-272
Author(s):  
Sudhir Pal Singh Rawat ◽  
◽  
Dr. Arnab Das ◽  
Dr. H.G.Virani Dr. H.G.Virani ◽  
Dr. Y.K.Somayajulu Dr. Y.K.Somayajulu
Keyword(s):  
Shallow Water ◽  
Arabian Sea ◽  
Ambient Noise

scholarly journals Analysis of wind-driven ambient noise in a shallow water environment with a sandy seabed

2008 ◽  
Vol 124 (3) ◽  
pp. EL157-EL162 ◽  
Author(s):  
D. P. Knobles ◽  
S. M. Joshi ◽  
R. D. Gaul ◽  
H. C. Graber ◽  
N. J. Williams
Keyword(s):  
Shallow Water ◽  
Ambient Noise ◽  
Water Environment ◽  
Shallow Water Environment

Real Time Acoustic Imaging by Holographic Interferometry

1980 ◽  
Vol 2 (4) ◽  
pp. 313-323 ◽  
Author(s):  
Amin Hanafy ◽  
Mauro Zambuto
Keyword(s):  
Real Time ◽  
Holographic Interferometry ◽  
Vibration Amplitude ◽  
Imaging System ◽  
Mechanical Vibration ◽  
Visual Image ◽  
Acoustic Imaging ◽  
Acoustic Image ◽  
Vibration Pattern ◽  
Amplitude Amplification

A two-step real time acoustic imaging system is presented. The system incorporates a novel acoustic image coupler which transfers an acoustical interference pattern from a water-bounded to an air-bounded surface with vibration amplitude amplification. An original technique termed step-biased real time holographic interferometry is used to convert the amplified mechanical vibration pattern, which carries all information about the insonified object, into a visual image with improved sensitivity.

An Experimental Underwater Acoustic Imaging System Using Multi-Beam Scanning

1980 ◽  
pp. 249-266 ◽  
Author(s):  
Kazuhiko Nitadori ◽  
Kunihiko Mano ◽  
Hiroshi Kamata
Keyword(s):  
Imaging System ◽  
Acoustic Imaging ◽  
Beam Scanning ◽  
Underwater Acoustic
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