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Title: Design of an active sonar for measuring bubble clouds under breaking waves.
Creator: Quant, Roberta Wendy., Florida Atlantic University, Glegg, Stewart A. L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis describes an active sonar mounted to an Autonomous Underwater Vehicle (AUV) for measuring bubble clouds below breaking waves. A new development is the application of a very broadband sonar signal-processing scheme for the sonar. It is shown that using the active sonar on an Autonomous Underwater Vehicle provides reliable data and that good results are obtained by using a correlation processor. This thesis describes the optimum processing procedure for this application, resolution,...
Show moreThis thesis describes an active sonar mounted to an Autonomous Underwater Vehicle (AUV) for measuring bubble clouds below breaking waves. A new development is the application of a very broadband sonar signal-processing scheme for the sonar. It is shown that using the active sonar on an Autonomous Underwater Vehicle provides reliable data and that good results are obtained by using a correlation processor. This thesis describes the optimum processing procedure for this application, resolution, and signal to noise constraints. Experimental results are given which show that bubbles can be imaged using an active sonar from an AUV platform. It was shown in the experimental results that the additive and the multiplicative processing produced good results for different situations. The multiplicative procedure was more consistent in the identification of bubble clouds than the additive process. One could see from the multiplicative images for the sea experiment where the bubble clouds were located while in the additive images one could only tell that a bubble cloud was identified.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/15792
Subject Headings: Sonar, Bubbles, Ocean waves
Format: Document (PDF)

Title: MICROPROCESSOR SONAR SYSTEM.
Creator: SHABIB, HASSAN MARWAN, Florida Atlantic University
Abstract/Description: This thesis presents the development of a microprocessor based navigational system. The integrated system is capable of determining depth to the bottom, distance to the surface, and velocity of a deep towed submersible. The system also alerts the user to any reduction to forward safe distance limit. A discussion of the hardware used to gather the data is presented. Software development is discussed in great detail. The system utilizes the Sixty Five Hundred microprocessor family. Advantages...
Show moreThis thesis presents the development of a microprocessor based navigational system. The integrated system is capable of determining depth to the bottom, distance to the surface, and velocity of a deep towed submersible. The system also alerts the user to any reduction to forward safe distance limit. A discussion of the hardware used to gather the data is presented. Software development is discussed in great detail. The system utilizes the Sixty Five Hundred microprocessor family. Advantages include cost effectiveness and application versatility.
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Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14008
Subject Headings: Microprocessors--Programming, Sonar
Format: Document (PDF)

Title: APPLICATION OF SIGNAL DECOMPOSITION TO IMPROVE TIME DELAY ESTIMATES FOR SYNTHETIC APERTURE SONAR MOTION COMPENSATION.
Creator: Gazagnaire, Julia, Beaujean, Pierre-Philippe, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Synthetic Aperture Sonar (SAS) provides the best opportunity for side-looking sonar mounted on underwater platforms to achieve high-resolution images. However, SAS processing requires strict constraints on resolvable platform motion. The most common approach to estimate this motion is to use the Redundant Phase Center (RPC) technique. Here the ping interval is set, such that a portion of the sonar array overlaps as the sensor moves forward. The time delay between the pings received on these...
Show moreSynthetic Aperture Sonar (SAS) provides the best opportunity for side-looking sonar mounted on underwater platforms to achieve high-resolution images. However, SAS processing requires strict constraints on resolvable platform motion. The most common approach to estimate this motion is to use the Redundant Phase Center (RPC) technique. Here the ping interval is set, such that a portion of the sonar array overlaps as the sensor moves forward. The time delay between the pings received on these overlapping elements is estimated using cross-correlation. These time delays are then used to infer the pingto-ping vehicle motion. Given the stochastic nature of the operational environment, some level of decorrelation between these two signals is likely. In this research, two iterative signal decomposition methods well suited for nonlinear and non-stationary signals, are investigated for their potential to improve the Time Delay Estimation (TDE). The first of this type, the Empirical Mode Decomposition (EMD) was introduced by Huang in the seminal paper, The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis and is the foundation for the algorithms used in this research. This method decomposes a signal into a finite sequence of simple components termed Intrinsic Mode Functions (IMFs). The Iterative Filter (IF) approach, developed by Lin, Wang and Zhou, builds on the EMD framework. The sonar signals considered in this research are complex baseband signals. Both the IF and EMD algorithms were designed to decompose real signals. However, the IF variant, the Multivariate Fast Iterative Filtering (MFIF) Algorithm, developed by Cicone, and the EMD variant, the Fast and Adaptive Multivariate Empirical Mode Decomposition (FAMVEMD) algorithm, developed by Thirumalaisamy and Ansell, preserve both the magnitude and phase in the decomposition and hence were chosen for this analysis.
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013795
Subject Headings: Sonar, Signal processing, Synthetic apertures
Format: Document (PDF)

Title: GENERATIVE ADVERSARIAL NETWORK DATA GENERATION FOR THE USE OF REAL TIME IMAGE DETECTION IN SIDE-SCAN SONAR IMAGERY.
Creator: McGinley, James Patrick, Dhanak, Manhar, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Automatic target recognition of unexploded ordnances in side scan sonar imagery has been a struggling task, due to the lack of publicly available side-scan sonar data. Real time image detection and classification algorithms have been implemented to combat this task, however, machine learning algorithms require a substantial amount of training data to properly detect specific targets. Transfer learning methods are used to replace the need of large datasets, by using a pre trained network on...
Show moreAutomatic target recognition of unexploded ordnances in side scan sonar imagery has been a struggling task, due to the lack of publicly available side-scan sonar data. Real time image detection and classification algorithms have been implemented to combat this task, however, machine learning algorithms require a substantial amount of training data to properly detect specific targets. Transfer learning methods are used to replace the need of large datasets, by using a pre trained network on the side-scan sonar images. In the present study the implementation of a generative adversarial network is used to generate meaningful sonar imagery from a small dataset. The generated images are then added to the existing dataset to train an image detection and classification algorithm. The study looks to demonstrate that generative images can be used to aid in detecting objects of interest in side-scan sonar imagery.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013394
Subject Headings: Sidescan sonar, Algorithms, Machine learning
Format: Document (PDF)

Title: Modeling the forward look sonar.
Creator: Barrault, Guillaume., Florida Atlantic University, Cuschieri, Joseph M.
Abstract/Description: A numerical model that simulates the operation of a Forward Look Scan Sonar (FLSS) has been developed in this thesis. The model discretizes the sonar-projected signal by a set of rays using a geometrical approach. Bending of the rays due to varying acoustic wave speed is neglected. Simulated raw sonar data are generated, and used as input in the sonar processing algorithms to generate sonar images. Using the model, the influence of, the most critical characteristics of the sonar, including...
Show moreA numerical model that simulates the operation of a Forward Look Scan Sonar (FLSS) has been developed in this thesis. The model discretizes the sonar-projected signal by a set of rays using a geometrical approach. Bending of the rays due to varying acoustic wave speed is neglected. Simulated raw sonar data are generated, and used as input in the sonar processing algorithms to generate sonar images. Using the model, the influence of, the most critical characteristics of the sonar, including phase variations among the channels, non-homogeneous channel amplitude, and the number of bad channels, on the quality of the sonar image is determined. The results of the model are compared to real data from a low frequency FLS sonar (250 KHz) and a high frequency FLS sonar (600 KHz). There is good matching between the simulation and the operation of the two sonars and the performance was markedly enhanced by using the modeling results.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/12733
Subject Headings: Sonar, Underwater acoustics, Remote submersibles
Format: Document (PDF)

Title: Fuzzy auto-detection of bottom mines.
Creator: Bauer, Eric John., Florida Atlantic University, Schock, Steven G.
Abstract/Description: An automatic mine detection method has been designed for the purpose of locating mine-like objects on the seabed in real time using a high frequency, high resolution side scan sonar. The processing flow includes a calculation of the average scattering function of the local environment, shadow detection, and a fuzzy logic clustering/fuzzy logic detection procedure for identifying mine-like shadows. An Autonomous Underwater Vehicle (AUV) equipped with a fuzzy detection system gives the Navy the...
Show moreAn automatic mine detection method has been designed for the purpose of locating mine-like objects on the seabed in real time using a high frequency, high resolution side scan sonar. The processing flow includes a calculation of the average scattering function of the local environment, shadow detection, and a fuzzy logic clustering/fuzzy logic detection procedure for identifying mine-like shadows. An Autonomous Underwater Vehicle (AUV) equipped with a fuzzy detection system gives the Navy the capability of rapidly locating bottom mines in littoral underwater environments during over-the-horizon operations.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/12705
Subject Headings: Submarine mines, Sonar, Fuzzy systems
Format: Document (PDF)

Title: Simulation of reflection tomographic images of underwater targets with the effect of vehicle motion sensing errors.
Creator: Quentin, Gwendoline., Florida Atlantic University, Schock, Steven G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The Buried Object Scanning Sonar (BOSS) is being developed at Florida Atlantic University to image targets buried under the seabed. Tomographic images are constructed using a sequence of sonar transmissions while the vehicle is moving. This motion causes image distortion and should be measured and removed by mapping the echoes received to an absolute coordinate system. The aim of this thesis is to develop and simulate a technique for generating BOSS images that provide an accurate...
Show moreThe Buried Object Scanning Sonar (BOSS) is being developed at Florida Atlantic University to image targets buried under the seabed. Tomographic images are constructed using a sequence of sonar transmissions while the vehicle is moving. This motion causes image distortion and should be measured and removed by mapping the echoes received to an absolute coordinate system. The aim of this thesis is to develop and simulate a technique for generating BOSS images that provide an accurate representation of target shape and size, by removing vehicle motion while mapping the image pixels. Synthetic acoustic data sets are generated by convolving the auto-correlated FM transmission pulse with the impulse response of an elastic sphere. Synthetic outputs of a Doppler velocity log and a 3-axis inertial measurement unit are generated to simulate vehicle motion. Noise is added to the sensor data to show the effects of motion sensor errors on image quality.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13040
Subject Headings: Ocean tomography, Sonar, Underwater navigation
Format: Document (PDF)

Title: A Deep Learning Approach To Target Recognition In Side-Scan Sonar Imagery.
Creator: Einsidler, Dylan, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Automatic target recognition capabilities in autonomous underwater vehicles has been a daunting task, largely due to the noisy nature of sonar imagery and due to the lack of publicly available sonar data. Machine learning techniques have made great strides in tackling this feat, although not much research has been done regarding deep learning techniques for side-scan sonar imagery. Here, a state-of-the-art deep learning object detection method is adapted for side-scan sonar imagery, with...
Show moreAutomatic target recognition capabilities in autonomous underwater vehicles has been a daunting task, largely due to the noisy nature of sonar imagery and due to the lack of publicly available sonar data. Machine learning techniques have made great strides in tackling this feat, although not much research has been done regarding deep learning techniques for side-scan sonar imagery. Here, a state-of-the-art deep learning object detection method is adapted for side-scan sonar imagery, with results supporting a simple yet robust method to detect objects/anomalies along the seabed. A systematic procedure was employed in transfer learning a pre-trained convolutional neural network in order to learn the pixel-intensity based features of seafloor anomalies in sonar images. Using this process, newly trained convolutional neural network models were produced using relatively small training datasets and tested to show reasonably accurate anomaly detection and classification with little to no false alarms.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013025
Subject Headings: Deep learning, Sidescan sonar, Underwater vision
Format: Document (PDF)

Title: Cross-correlation of phase centers to estimate direction-of-arrival for a 3-row bathymetric sidescan sonar.
Creator: Crenshaw, Edward T. G., Florida Atlantic University, LeBlanc, Lester R.
Abstract/Description: A new method for calculating the direction-of-arrival (DOA), and thus the bathymetry of the seafloor, is presented. This method will calculate the DOA directly from the phase difference between the phase centers of the array. In parallel, a bathymetric sidescan sonar system originally built at Woods Hole and now here at Florida Atlantic University's Department of Ocean Engineering, was completed. Once this system was working, the above mentioned signal analysis regime will be implemented on...
Show moreA new method for calculating the direction-of-arrival (DOA), and thus the bathymetry of the seafloor, is presented. This method will calculate the DOA directly from the phase difference between the phase centers of the array. In parallel, a bathymetric sidescan sonar system originally built at Woods Hole and now here at Florida Atlantic University's Department of Ocean Engineering, was completed. Once this system was working, the above mentioned signal analysis regime will be implemented on actual data to test its validity.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/12738
Subject Headings: Sidescan sonar, Bathymetric maps, Signal processing
Format: Document (PDF)

Title: Target signature for a periodic structure using a low-frequency broadband side-scan simulator.
Creator: Dietz, Jerrold Edward Gilbert., Florida Atlantic University, LeBlanc, Lester R.
Abstract/Description: Many acoustic targets of interest contain features that are periodic in space. This thesis demonstrates that a chirp waveform, 2 kHz to 12 kHz, can detect repetitive structures with periods in the range of 0.125 m to 0.75 m. As aspect angle increases from 0 deg to 90 deg, a frequency shift in the range of 830 Hz to 4800 Hz will occur as the period decreases from 0.75 to 0.125 m. It follows that, spectral analysis can aid in target identification. A sonar propagation model has been developed...
Show moreMany acoustic targets of interest contain features that are periodic in space. This thesis demonstrates that a chirp waveform, 2 kHz to 12 kHz, can detect repetitive structures with periods in the range of 0.125 m to 0.75 m. As aspect angle increases from 0 deg to 90 deg, a frequency shift in the range of 830 Hz to 4800 Hz will occur as the period decreases from 0.75 to 0.125 m. It follows that, spectral analysis can aid in target identification. A sonar propagation model has been developed to simulate the acoustic backscattered energy of a target with periodic characteristics in the presence of seafloor scattering. Examining the spectral components, with appropriate time gating, can achieve a gain of 7 dB at 3100 m.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/12788
Subject Headings: Sidescan sonar, Underwater acoustics, Scattering (Physics)
Format: Document (PDF)

Title: Temporal and spatial variation in habitat characteristics of tilefish (Lopholatilus chamaeleonticeps) off the east coast of Florida.
Creator: Able, Kenneth W., Grimes, Churchill B., Jones, Robert S., Twichell, David C., Harbor Branch Oceanographic Institute
Date Issued: 1993
PURL: http://purl.flvc.org/FCLA/DT/3172857
Subject Headings: Tilefish, Marine sediments --Florida, Carbonates, Sidescan sonar, Oceanographic submersibles
Format: Document (PDF)

Title: Obstacle detection by a forward-looking sonar integrated in an autonomous underwater vehicle.
Creator: Martin, Antoine., Florida Atlantic University, An, Edgar, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis describes the implementation of a commercially available forward looking sonar (FLS) in an autonomous underwater vehicle (AUV) modified for the task of reactive obstacle detection. Any obstacle lying in the vehicle's path is a potential mission-terminating threat. Inclusion of a forward looking sensor would provide valuable information to the AUV. Threat assessment and navigation would use this information in order to avoid obstacles. The system used for this project is an 8...
Show moreThis thesis describes the implementation of a commercially available forward looking sonar (FLS) in an autonomous underwater vehicle (AUV) modified for the task of reactive obstacle detection. Any obstacle lying in the vehicle's path is a potential mission-terminating threat. Inclusion of a forward looking sensor would provide valuable information to the AUV. Threat assessment and navigation would use this information in order to avoid obstacles. The system used for this project is an 8-element transducer FLS at 200 kHz. The sonar control software is done in DOS on a dedicated personal computer in a PC/104 form factor. A variable cell-size grid occupancy search method is used to detect objects in the vehicle path. This thesis describes how this sonar is used for the obstacle detection task (software), how it is integrated (hardware and network) in the AUV and what are the results obtained with the system.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/12691
Subject Headings: Oceanographic submersibles--Computer simulation, Sonar, Underwater navigation
Format: Document (PDF)

Title: Middle frequency target characteristics.
Creator: Castagnet, Sabine., Florida Atlantic University, Cuschieri, Joseph M.
Abstract/Description: The problem of inverse scattering where the scattering structure is unknown, and the physical properties are predicted from the measured echo when the target is insonified with known waveforms, is investigated in this thesis. The scattering structure studied is a submerged, evacuated, spherical elastic shell. The formulation of the echo is carried out using thin shell theory for low and middle frequency range, which basically assumes that shear stresses are negligible. The echo is...
Show moreThe problem of inverse scattering where the scattering structure is unknown, and the physical properties are predicted from the measured echo when the target is insonified with known waveforms, is investigated in this thesis. The scattering structure studied is a submerged, evacuated, spherical elastic shell. The formulation of the echo is carried out using thin shell theory for low and middle frequency range, which basically assumes that shear stresses are negligible. The echo is characterized by the form function in the frequency domain, and the impulse response in the time domain. The results of this thesis show that when using a chirp signal with a 200-250kHz bandwidth as the incident waveform, both the material and size of the shell can be recovered. However, the exact thickness of the shell wall couldn't be extracted.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15423
Subject Headings: Elastic plates and shells, Sonar, Frequency response (Dynamics)
Format: Document (PDF)

Title: A three-dimensional forward-look sonar simulation model.
Creator: Gazagnaire, Julia., Florida Atlantic University, Cuschieri, Joseph M., Beaujean, Pierre-Philippe
Abstract/Description: The aim of this thesis is to develop a simulation tool, The 3-D Forward-Look Sonar Simulation Model (3-D-FLSSM), for the 3-D Forward Look Sonar or equivalent that provides insight to the defining characteristics of the sonar system that affect the image quality and the data processing. The simulator includes a representation of the acoustic environment, which incorporates a flat seafloor and spherical target, both of which are assumed to a have small-scale roughness (much less than the...
Show moreThe aim of this thesis is to develop a simulation tool, The 3-D Forward-Look Sonar Simulation Model (3-D-FLSSM), for the 3-D Forward Look Sonar or equivalent that provides insight to the defining characteristics of the sonar system that affect the image quality and the data processing. The simulator includes a representation of the acoustic environment, which incorporates a flat seafloor and spherical target, both of which are assumed to a have small-scale roughness (much less than the acoustic wavelength) associated with them. The backscatter from the target and the seafloor are calculated using the Rayleigh-Rice approximation implementing Kuo's backscattering cross section. The simulator is capable of modeling targets of various shapes and sizes. The 3-D-FLSSM assumes a plane wave approximation and a constant sound velocity throughout the water column. The final product is a simulation tool with a focus on shallow water littoral acoustics, which can be used to define the sonar hardware and processing software necessary to meet various operational requirements.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13002
Subject Headings: Sonar--Computer simulation, Underwater acoustics, Remote submersibles
Format: Document (PDF)

Title: Beaked whale auditory evoked potential hearing measurements.
Creator: Cook, Mandy L. H., Varela, Rene A., Goldstein, Juli D., McCulloch, Stephen D., Bossart, Gregory D., Finneran, James J., Houser, Dorian, Mann, David A., Harbor Branch Oceanographic Institute
Date Issued: 2006
PURL: http://purl.flvc.org/FCLA/DT/2796070
Subject Headings: Beaked whales, Sonar, Auditory Perception --physiology, Marine animals --Vocalization, Echolocation (Physiology)
Format: Document (PDF)

Title: 3D Reconstruction of Simulated Bridge Pier Local Scour Using Green Laser and HydroLite Sonar.
Creator: Banyhany, Musab, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: Scour is the process of sediment erosion around bridge piers and abutments due to natural and man-made hydraulic activities. Excessive scour is a critical problem that is typically handled by enforcing design requirements that make the submerged structures more resilient. The purpose of this research is to demonstrate the feasibilities of the Optical- Based Green Laser Scanner and HydroLite Sonar in a laboratory setting to capture the 3D profile of simulated local scour holes. The Green Laser...
Show moreScour is the process of sediment erosion around bridge piers and abutments due to natural and man-made hydraulic activities. Excessive scour is a critical problem that is typically handled by enforcing design requirements that make the submerged structures more resilient. The purpose of this research is to demonstrate the feasibilities of the Optical- Based Green Laser Scanner and HydroLite Sonar in a laboratory setting to capture the 3D profile of simulated local scour holes. The Green Laser had successfully reconstructed a 3D point-cloud imaging of scour profiles under both dry and clear water conditions. The derived scour topography after applying water refraction correction was compared with the simulated scour hole, and was within 1% of the design dimensions. The elevations at the top and bottom surfaces of the 6.5-inch scour hole were -46.6 and -53.11 inches from the reference line at the origin (0,0,0) of the laser scanner. The HydroLite Sonar recorded hydrographical survey points of the scour’s interior surface. The survey points were then processed using MATLAB to obtain a 3D mesh triangulation.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00005995
Subject Headings: Scour at bridges, Sonar, Lasers, Scour at bridges--Evaluation--Technique
Format: Document (PDF)

Title: Digital signal processing for a high-resolution three-dimensional sonar imaging system for autonomous underwater vehicles.
Creator: Cao, Ping., Florida Atlantic University, Cuschieri, Joseph M., Sudhakar, Raghavan, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this dissertation, the digital signal processing techniques required for a 3-D sonar imaging system are examined. The achievable performance of the generated images is investigated by using a combination of theoretical analysis, computer simulation and field experiments. The system consists of a forward looking sonar, with separate projector and receiver. The projector is a line source with an 80 degrees by 1.2 degree beam pattern, which is electronically scanned within a 150 degree sector...
Show moreIn this dissertation, the digital signal processing techniques required for a 3-D sonar imaging system are examined. The achievable performance of the generated images is investigated by using a combination of theoretical analysis, computer simulation and field experiments. The system consists of a forward looking sonar, with separate projector and receiver. The projector is a line source with an 80 degrees by 1.2 degree beam pattern, which is electronically scanned within a 150 degree sector. The receiver is a multi element line array, where each transducer element has a directivity pattern that covers the full sector of view, that is 150 degrees by 80 degrees. The purpose of this sonar system is to produce three dimensional (3-D) images which display the underwater topography within the sector of view up to a range of 200 meters. The principle of operation of the proposed 3-D imaging system differs from other commonly used systems in that it is not based on the intensity of backscatter. The geometries of the targets are obtained from the delay and direction information that can be extracted from the signal backscatter. The acquired data is further processed using an approach based on sequential Fourier transforms to build the 3-D images. With careful selection of the system parameters, the generated images have sufficient quality to be used for AUV tasks such as obstacle avoidance, navigation and object classification. An approach based on a sophisticated two dimensional (2-D) autoregressive (AR) model is explored to further improve the resolution and generate images with higher quality. The real time processing requirements for image generation are evaluated, with the use of dedicated Digital Signal Processing (DSP) chips. A pipeline processing model is analyzed and developed on a selected system.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12317
Subject Headings: Sonar, Signal processing--Digital techniques, Three-dimensional display systems, Submersibles
Format: Document (PDF)

Title: Multi-aspect imaging of cylindrical targets using a wide aperture FM sonar.
Creator: Rivalan, Gregory., Florida Atlantic University, Schock, Steven G.
Abstract/Description: The purpose of the thesis is to investigate a multi-aspect reflection technique to generate 3D images of buried cylinders using the Buried Object Scanning Sonar (BOSS). Target imagery is constructed using a sequence of acoustic echoes generated as the sonar approaches and passes the buried target. However, for the sake of simplicity, the influence of the sediment on the scattering field will not be considered. This thesis investigates the multi-aspect technique by generating synthetic images...
Show moreThe purpose of the thesis is to investigate a multi-aspect reflection technique to generate 3D images of buried cylinders using the Buried Object Scanning Sonar (BOSS). Target imagery is constructed using a sequence of acoustic echoes generated as the sonar approaches and passes the buried target. However, for the sake of simplicity, the influence of the sediment on the scattering field will not be considered. This thesis investigates the multi-aspect technique by generating synthetic images of cylindrical targets to determine both the best method and the sonar parameters for reconstructing the shape of an elastic cylinder. Recommendations for deploying BOSS-252 and setting sonar parameters are provided based on quantitative measurements of the simulated images of cylindrical targets.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13268
Subject Headings: Three-dimensional display systems, Sonar, Sound-waves--Scattering, Underwater acoustics, Underwater exploration
Format: Document (PDF)

Title: Sediment classification of the sea floor using the Chirp Sonar and the Biot model.
Creator: Beaujean, Pierre-Philippe, Florida Atlantic University, LeBlanc, Lester R.
Abstract/Description: A new method is proposed to infer the geotechnical properties of the sea floor from its response to the frequency-modulated pulses emitted by the subbottom profiler called Chirp Sonar. The environment is assumed to be a multilayered medium, composed of homogeneous layers, or an inhomogeneous half-space with depth-dependent properties. The acoustic response of the sediment is computed using the Biot-Stoll theory. The Levenberg-Marquardt method is applied to fit the synthetic response to the...
Show moreA new method is proposed to infer the geotechnical properties of the sea floor from its response to the frequency-modulated pulses emitted by the subbottom profiler called Chirp Sonar. The environment is assumed to be a multilayered medium, composed of homogeneous layers, or an inhomogeneous half-space with depth-dependent properties. The acoustic response of the sediment is computed using the Biot-Stoll theory. The Levenberg-Marquardt method is applied to fit the synthetic response to the experimental response of an homogeneous layer overlying the sea floor. The porosity, the permeability, the mean grain diameter, the mass density, the bulk modulus and the shear modulus within this sediment layer can be estimated. A multilayered medium with depth-dependent properties could be applied to this inversion technique in the future.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15208
Subject Headings: Marine sediments--Acoustic properties, Underwater acoustics--Measurement, Ocean bottom, Sonar
Format: Document (PDF)

Title: Visualization of buried objects in three-dimensional acoustic data acquired by a buried object scanning sonar.
Creator: Tellier, Arnaud Marc., Florida Atlantic University, Schock, Steven G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The common approach for finding objects buried under the seabed is to use a single channel chirp reflection profiler. Reflection profiles lack information on target location, geometry and size. This thesis investigates methods for visualizing buried objects in noisy 3D acoustic data acquired by a small aperture scanning sonar. Various surface and volume rendering methods are tested with synthetic datasets containing fluid loaded spheres and with experimental data acquired with a 4-by-8 planar...
Show moreThe common approach for finding objects buried under the seabed is to use a single channel chirp reflection profiler. Reflection profiles lack information on target location, geometry and size. This thesis investigates methods for visualizing buried objects in noisy 3D acoustic data acquired by a small aperture scanning sonar. Various surface and volume rendering methods are tested with synthetic datasets containing fluid loaded spheres and with experimental data acquired with a 4-by-8 planar hydrophone array towed over buried objects with various aspects and size. The Maximum Intensity Projection is the best of the tested methods for real-time visualization of the data where a global overview of the targets is needed. A surface rendering technique such as the Marching Cubes is useful for offline measurement of the geometry and size of buried objects selected by the operator.
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Date Issued: 1999
PURL: http://purl.flvc.org/fcla/dt/15682
Subject Headings: Three-dimensional display systems, Sonar, Sound-waves--Scattering, Computer graphics
Format: Document (PDF)

FAU Theses and Dissertations (20)	+ -
HBOI Faculty Contributions (3)	+ -

Sonar (15)	+ -
Sidescan sonar (5)	+ -
Underwater acoustics (4)	+ -
Remote submersibles (3)	+ -
Sonar--Computer simulation (3)	+ -

Three-dimensional display systems (3)	+ -
Signal processing (2)	+ -
Sound-waves--Scattering (2)	+ -
Underwater acoustics--Computer simulation (2)	+ -
Underwater navigation (2)	+ -
Algorithms (1)	+ -
Auditory Perception --physiology (1)	+ -
Automatic control (1)	+ -
Bathymetric maps (1)	+ -
Beaked whales (1)	+ -
Bubbles (1)	+ -
Carbonates (1)	+ -
Computer graphics (1)	+ -
Deep learning (1)	+ -
Echolocation (Physiology) (1)	+ -
Elastic plates and shells (1)	+ -
Electric filters (1)	+ -
Frequency response (Dynamics) (1)	+ -
Fuzzy logic (1)	+ -
Fuzzy systems (1)	+ -
Lasers (1)	+ -
Machine learning (1)	+ -
Marine animals --Vocalization (1)	+ -
Marine sediments --Florida (1)	+ -
Marine sediments--Acoustic properties (1)	+ -

Electronic Thesis or Dissertation (20)	+ -
article (3)	+ -

Florida Atlantic University (20)	+ -
College of Engineering and Computer Science (10)	+ -
Department of Ocean and Mechanical Engineering (9)	+ -
Cuschieri, Joseph M. (5)	+ -
Schock, Steven G. (4)	+ -

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