A High-Resolution Acoustic Imaging System to Map Interior Fish Morphology

2015 ◽  
Vol 49 (2) ◽  
pp. 59-69 ◽  
Author(s):  
Dezhang Chu ◽  
J. Michael Jech ◽  
Stan D. Tomich ◽  
Lawrence C. Hufnagle
Keyword(s):  
Imaging System ◽  
Vertical Plane ◽  
Acoustic Imaging ◽  
Target Strength ◽  
Planar Arrays ◽  
Acoustic Images ◽  
Fish Morphology ◽  
Acoustic Target ◽  
Receive Channel ◽  
Computer Controlled

AbstractAn acoustic imaging microtome system (AIMS) was constructed to map the internal structure of fish. The system consists of two pairs of high-frequency (4.5 MHz) transmit-and-receive planar arrays, with one pair in the vertical plane and the other in the horizontal plane. AIMS provides a series of acoustic images, analogous to microtome slices, along the length of a fish by combining electronically controlled sequential acoustic transmissions and receptions over 224 channels and a computer-controlled mechanical device that moves the acoustic arrays lengthwise along the fish. AIMS measures the acoustic attenuation (extinction) along the direct ray paths of each transmit-receive channel pair that penetrates the fish body in a bistatic configuration. This results in a 2-D image of the interior morphology with 4- to 5-mm resolution. The images can provide morphological information on the fish's cheekbone, backbone, rib bone, skull, fins, stomach, and swimbladder, which is important for accurately modeling fish acoustic target strength, especially for non-swimbladder-bearing fish species.

Development of acoustic target strength near-field equation for underwater vehicles

2018 ◽  
Vol 233 (3) ◽  
pp. 714-721
Author(s):  
Jae-Yong Kim ◽  
Suk-Yoon Hong ◽  
Byung-Gu Cho ◽  
Jee-Hun Song ◽  
Hyun-Wung Kwon
Keyword(s):  
Field Equation ◽  
Plane Wave ◽  
Pressure Field ◽  
Near Field ◽  
Target Strength ◽  
Detection Capability ◽  
Weapon Systems ◽  
Active Sonar ◽  
Acoustic Target ◽  
Definition Of

For modern weapon systems, the most important factor in survivability is detection capability. Acoustic target strength is a major parameter of the active sonar equation. The traditional target strength equation used to predict the re-radiated intensity for the far field is derived with a plane-wave assumption. In this study, a near-field target strength equation was derived without a plane-wave assumption for a polygonal plate. The target strength equation for polygonal plates, which is applicable to the near field, is provided by the Helmholtz–Kirchhoff formula that is used as the primary equation for solving the re-radiated pressure field. A generalized definition of the sonar cross section is suggested that is applicable to the near field. In comparison experiments for a cylinder, the target strength equation for polygonal plates in near field was executed to verify the validity and accuracy of the analysis. In addition, an underwater vehicle model was analyzed with the developed near-field equation to confirm various parameter effects such as distance and frequency.

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

An Underwater Focused Acoustic Imaging System

1982 ◽  
pp. 607-617
Author(s):  
P. Maguer ◽  
J. F. Gelly ◽  
C. Maerfeld ◽  
G. Grall
Keyword(s):  
Imaging System ◽  
Acoustic Imaging

scholarly journals The study of the acoustic target strength of Chub mackerel in the northwestern Pacific Ocean in situ

Trudy VNIRO ◽  
2021 ◽  
Vol 184 ◽  
pp. 73-86
Author(s):  
M.Yu. Kuznetsov ◽  
◽  
V.I. Polyanichko ◽  
E.V. Syrovatkin ◽  
I.A. Ubarchuk ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Target Strength ◽  
Northwestern Pacific ◽  
Chub Mackerel ◽  
Northwestern Pacific Ocean ◽  
Acoustic Target

First in situ estimates of acoustic target strength of Antarctic toothfish (Dissostichus mawsoni)

2018 ◽  
Vol 206 ◽  
pp. 79-84 ◽  
Author(s):  
Richard L. O’Driscoll ◽  
Simonepietro Canese ◽  
Yoann Ladroit ◽  
Steve J. Parker ◽  
Laura Ghigliotti ◽  
...  
Keyword(s):  
Target Strength ◽  
Antarctic Toothfish ◽  
Dissostichus Mawsoni ◽  
Acoustic Target

scholarly journals Acoustic Target Strength of the Endangered Chinese Sturgeon (Acipenser sinensis) by Ex Situ Measurements and Theoretical Calculations

2018 ◽  
Vol 8 (12) ◽  
pp. 2554 ◽  
Author(s):  
Hui Zhang ◽  
Junyi Li ◽  
Chongrui Wang ◽  
Chengyou Wang ◽  
Jinming Wu ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Breeding Population ◽  
Ex Situ ◽  
Target Strength ◽  
Effective Management ◽  
Chinese Sturgeon ◽  
Acipenser Sinensis ◽  
Acoustic Target ◽  
The Mean ◽  
Db Difference

The Chinese sturgeon, Acipenser sinensis, is a large anadromous and highly endangered protected species. The assessment of its breeding population in the Yangtze River is critically important for effective management and population preservation. Currently, hydroacoustic methods have been widely used to study the adult sturgeons in the river, whereas the acoustic target strength (TS) characteristics of the species have not been studied. In this study, the TS of Chinese sturgeon was carefully evaluated both by ex situ measurements and theoretical calculations. Six Chinese sturgeons (Body Length (BL): 74.0−92.6 cm) were measured by a 199 kHz split echosounder in a 10-m deep net cage. The computed tomography of a Chinese sturgeon (BL: 110.0 cm) was conducted and the Kirchhoff ray mode (KRM) method was used to estimate the theoretical TS. As a result, the mean ex situ TS range of the six specimens was from −26.9 to −31.4 dB, which was very close to the KRM estimation (~1 dB difference). Then, the KRM method was used to predict the TS of Chinese sturgeon as a function of BL in six frequencies commonly used in freshwater environments and to estimate the TS of a representative adult Chinese sturgeon (250 cm) as a function of frequency and tilt angle. This study can provide a good basis for future hydroacoustic studies on the critically endangered Chinese sturgeon.

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