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Statistical evaluation of 80 kHz shallow-water seafloor reverberation
(NATO. SACLANTCEN, 1997)
In this work a comparison is presented between 80 kHz reverberation statistics obtained at shallow water sites around Sardinia and Sicily. The data include measurements from several distinct bottom provinces, including ...
Seabed characterization by inversion of parametric sonar data: selection of the cost function
(NATO. SACLANTCEN, 1997)
A class of possible cost functions to be used in model-based estimation of bottom parameters from highfrequency backscatter signals is introduced. The cost is based on the properttes of the signal in the wavelettransformed ...
Dynamic attenuation extraction of seafloor sediments from very high resolution acoustic data
(NATO. SACLANTCEN, 1997)
An approach to acquire geophysical information of seabed sediments as derrved from acoustic attenuation rs described. Using thefrequencies corresponding to the signal power spectrum maximum and a point 3 dB below, signal ...
Shallow-water seafloor characterization for high-frequency multibeam echosounder: image segmentation using angular backscatter
(NATO. SACLANTCEN, 1997)
Sonar images from multibeam echosounders are submitted to various degradations, partly due to the sensor itself: Signal artefacts and corresponding corrections are presented, both for signal processing and for array ...
Determination of velocity profile and sea bed characteristics from high frequency pulse propagation in a shallow water Mediterranean environment
(NATO. SACLANTCEN, 1997)
Time-domain features of shallow water Mediterranean and Yellow Sea data are simulated for frequency band widths of 0.8 kHz with a centralfrequency of 3.2 kHz. Contour plots of pulse arrivals in time and depth are analyzed ...
The effect source movements on shallow water bottom backscatter
(NATO. SACLANTCEN, 1997)
The time-evolution model BORIS is used to study the effects of source movements on bottom backscatter. Changes in the backscattend time domain signals as functions of source depth, position and incident angles are simulated ...
High-resolution characterization of seafloor sediments for modeling acoustic backscatter
(NATO. SACLANTCEN, 1997)
Quantitative information on fine-scale sediment inhomogeneity is extremely scarce and sorely needed for developing realistic volume scattering models. To address this deficiency, we present a novel approach for sediment ...
Relating in situ shear wave velocity to void ratio and grain size for unconsolidated marine sediments
(NATO. SACLANTCEN, 1997)
Recent advances in field hardware have meant that it has become possible to measurein situ shear wave velocity in the upper few decimetres of sea floor sediment in a routine manner. It is known that shear wave velocity can ...
A high frequency approach for seabed vegetation characterization
(NATO. SACLANTCEN, 1997)
This paper focuses on the characterization of seabed vegetation, an interesting problem in a lot of Mediterranean sea coastal sites since water quality and pollution degree can be efficaciously solved by investigating the ...
Texture analysis of sidescan sonar imagery using statistical scattering models
(NATO. SACLANTCEN, 1997)
It is shown that the generalised K-distribution provides a good fir to the amplrtude statisttcs of sonar imagery from several different types of seabed sediment. A number of possible explanations for the Ricean nature of ...