Acoustical imaging of buried objects in bottom sediment by using focused ultrasonic transducer

1978 ◽  
Vol 64 (S1) ◽  
pp. S142-S142
Author(s):  
M. Ohgaki ◽  
R. Shimizu ◽  
H. Miyazawa ◽  
M. Okujima
Keyword(s):  
Bottom Sediment ◽  
Ultrasonic Transducer ◽  
Buried Objects ◽  
Acoustical Imaging

Acoustical imaging of an object buried in seafloor sediment by using a focused ultrasonic transducer

1980 ◽  
Vol 67 (5) ◽  
pp. 1603-1607 ◽  
Author(s):  
Masakatsu Ohgaki ◽  
Ryoji Shimizu ◽  
Hisashi Miyazawa ◽  
Motoyoshi Okujima
Keyword(s):  
Ultrasonic Transducer ◽  
Acoustical Imaging ◽  
Seafloor Sediment

RISK ASSESSMENT OF SEAFLOOR WASTE: ACOUSTICAL IMAGING OF BURIED WASTE

2005 ◽  
Vol 13 (02) ◽  
pp. 385-401 ◽  
Author(s):  
ANDREA CAITI ◽  
MARIA PALMESE ◽  
ANDREA TRUCCO
Keyword(s):  
Reflection Coefficient ◽  
Measurement Techniques ◽  
Small Dimension ◽  
Acoustic Image ◽  
Buried Objects ◽  
Sediment Volume ◽  
Impedance Contrast ◽  
Random Grid ◽  
Segmentation Approach ◽  
Acoustical Imaging

This work describes some of the ongoing activities in the framework of the EU-sponsored project SITAR aimed at developing acoustic methods for imaging of waste barrels/containers of small dimension buried in unconsolidated sea sediments. In particular, the work relies on acoustic sub-bottom scattering measurement techniques, with adaptive geometrical configuration of the transmitting/receiving system. The approach ultimately leads to a full 3D measurement of the acoustic scattered field, including bottom and sub-bottom effects, plus the scattering due to buried objects in the scene. The 3D dense acoustic image is then processed in order to automatically extract relevant object(s) features, as size, 3D orientation, impedance contrast; this is obtained through a sequence of processing steps including filtering, enhancement, restoration and image segmentation. Preliminary results obtained with simulative data are presented: data are obtained by modeling the surfaces of both seabed and object(s) as a dense, random grid of discrete scatterers, following the Rayleigh reflection coefficient, and integrating the response of the scatterers. The effects due to absorption and refraction moving from water to sediments are also considered. Sediment volume inhomogeneities are modeled by a random distribution of small asymmetric scattering volumes, characterized by their 3D dimensions, density, and reflection coefficient. A volume growing segmentation approach has been applied, showing efficient segmentation capabilities, and robustness to uncertainty.

Nanoparticles Generation using Mono-disperse Droplets by an Ultrasonic Transducer

2020 ◽  
Vol 140 (2) ◽  
pp. 37-42
Author(s):  
Nozomu Fujimoto ◽  
Takefumi Kanda ◽  
Masaya Katsuta ◽  
Yusaku Sakata ◽  
Yoshiaki Yamada ◽  
...  
Keyword(s):  
Ultrasonic Transducer

Detection and characterisation of buried objects using infrared thermography enhanced by microwave heating

2002 ◽  
Author(s):  
Arnaud Jacotin ◽  
Elodie Bachelier ◽  
Francois Liousse ◽  
Pierre Millan
Keyword(s):  
Microwave Heating ◽  
Infrared Thermography ◽  
Buried Objects

ANALYSIS OF ACCUMULATION AND DISTRIBUTION OF LEAD IN THE SYSTEM WATER-BOTTOM SEDIMENTS IN THE BACH DANG ESTUARY (VIETNAM)

2017 ◽  
pp. 62-66
Author(s):  
Truong Van Tuan ◽  
Irina Vladimirovna Volkova
Keyword(s):  
Bottom Sediment ◽  
Bottom Sediments ◽  
Water Samples ◽  
Suspended Solids ◽  
Natural Habitat ◽  
Bottom Layer ◽  
Sediment Samples ◽  
Natural Breeding ◽  
System Water ◽  
Water Bottom

Research was held in the estuary of the river Bach Dang (Dongbay community, Rakhtay district, Hai Phong, Vietnam) in June, 2012 - May, 2013. Concentration of lead was studied in water, suspended solids and bottom sediment. Clam beach (natural breeding environment of Meretrix lyrata ) was inspected regularly, every month. Water samples were taken 6 times from the bottom layer 10 cm down the bottom, once per 3 hours in each of 12 investigated zones. Bottom sediment samples were taken at the depth 2 cm. The findings show that lead accumulates mainly in suspended solids (23.3 mg/kg) and in bottom sediment (14.31 mg/kg), in water it is in small quantities (0.003 mg/kg). Analysis of bottom sediment samples taken in different places showed that they have even leadcontent, lead is distributed uniformly, localization of contaminations is not found. The results obtained can be assumed as the basis for investigating lead accumulation and its excretion by clam Meretrix lyrata organisms in the natural habitat.

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