Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"sidescan"”.
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A bathymetric sidescan sonar system
The design and construction of a bathymetric sidescan sonar system capable of operation over a 39 degree vertical sector is described. Field tests conducted at a dam site indicate that the completed system does not function as required. This is due to errors in the sonar depth measurement which are …
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Signal direction-of-arrival and amplitude estimation for multiple-row bathymetric sidescan sonars
In practical applications with bathymetric sidescan sonars, the multipath reflections and other directional interferences are the key limiting factors for a better performance. This thesis proposes a new scheme to deal with the interferences using a multiple-row bathymetric sidescan sonar. Instead …
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Improving the Capabilities of Swath Bathymetry Sidescan Using Transmit Beamforming and Pulse Coding
Swath bathymetry sidescan (SBS) sonar and the angle-of-arrival processing that underlies these systems has the capability to produce much higher resolution three dimensional imagery and bathymetry than traditional beamformed approaches. However, the performance of these high resolution systems is …
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Signal direction-of-arrival and amplitude estimation for multiple-row bathymetric sidescan sonars
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1998.
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Algorithms and Data Structures for Automated Change Detection and Classification of Sidescan Sonar Imagery
… detection by visually comparing historical sidescan sonar imagery (SSI) collected by a sidescan sonar with recently collected SSI in an attempt to identify objects (which might be explosive mines) placed at sea since the last time the area was surveyed. This dissertation presents a data …
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POLYMETALLIC NODULE ABUNDANCE ESTIMATION USING SIDESCAN SONAR: A QUANTITATIVE APPROACH USING ARTIFICIAL NEURAL NETWORK
… Neural Network (ANN). Data used are geotagged Sidescan Sonar (SSS) seabed backscatter images and seabed photographs collected using an Autonomous Underwater Vehicle (AUV) within the CCFZ. Compared to an underwater camera, the SSS provides a much larger area of coverage, effectively increasing …
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Measurements and dynamics of multiple scale bedforms in tidally energetic environments
… 2 to expand the functionality of low-mounted sidescan sonars by utilizing sonar shadows to estimate bedform height and asymmetry. Empirical models are generated to account for realistic variability in the seabed and the method is validated with bathymetric observations of wave-orbital ripples …
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Measurements and dynamics of multiple scale bedforms in tidally energetic environments
… 2 to expand the functionality of low-mounted sidescan sonars by utilizing sonar shadows to estimate bedform height and asymmetry. Empirical models are generated to account for realistic variability in the seabed and the method is validated with bathymetric observations of wave-orbital ripples …
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Multisensor modeling underwater with uncertain information
… bathymetric surveying (Sea Beam), towed sidescan bathymetry (Sea MARC II), towed sidescan acoustic imagery (Sea MARC I & II), and high-resolution scanning sonar aboard a remotely operated vehicle. A multisensor application combines Sea Beam bathvmetry and Sea MARC I intensity models. …
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Geophysical Studies of Oceanic Core Complexes: The Mid-Atlantic Ridge, 13 - 14°N
… The data presented here include: deep-towed TOBI sidescan sonar and tri-axial magnetometer data, shipboard gravity and bathymetric data, and detailed seabed sampling results. High resolution sidescan sonar data reveal that active core complexes in this region are associated with a neovolcanic …
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Stratigraphic evolution of Las Vegas Bay, Lake Mead, Nevada: 1935--2002
… on stratigraphy of the basin. Mapping, seismic, sidescan sonar and bathymetry surveys, in conjunction with sediment cores, LPSA and 137Cs analyses were integrated to develop a temporal basin filling model for Las Vegas Bay. The evolution of the basin is divided into two periods based on lake …
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The geological evolution and sedimentary dynamics of Hout Bay, South Africa
… collect detailed and comprehensive bathymetric, sidescan sonar, magnetic, seismic and beach profiling data. Collectively these data can be used to map offshore geological units as well as infer how Hout Bay has responded to the varying changes in sea-level throughout the Quaternary and allow for …
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Late cenozoic shallow marine diamond placers off the northern Sperrgebiet, Namibia
… Using detailed geophysical survey data (Sidescan Sonar and Multi-beam Bathymetry), the deposition of diamonds at these sites were modelled in GIS-based reconstructions. The diamond size frequency distribution (SFO) of the Shallow Marine (0 to -30 m) deposits in the study area is similar …
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Observations and modeling of sand transport in a wave dominated environment
… were observed during storms using a rotary sidescan sonar and were found to be wave orbital scale ripples. The onshore migration of these ripples was forced by non-linear wave velocities, and could be related to a simple bedload model. Observations of suspended sand flux were calculated from …
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Seafloor ripples created by waves from Hurricane Ivan on the west Florida shelf
… of buried mines at sub-critical angles. Sidescan sonar data of ripples on the west Florida shelf were collected as part of ONR's Ripples Departmental Research Initiative (DRI) September 26-29th and November 7-9th, 2004. Hurricane Ivan, the strongest storm of the 2004 hurricane season, …
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Seafloor ripples created by waves from hurricane Ivan on the west Florida shelf
… of buried mines at sub-critical angles. Sidescan sonar data of ripples off on the west Florida shelf were collected as part of ONR's Ripples Departmental Research Initiative (DRI) September 26-29th and November 7-9th, 2004. Hurricane Ivan, the strongest storm of the 2004 hurricane season, …
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Characterization of underwater target geometry from Autonomous Underwater Vehicle sampling of bistatic acoustic scattered fields
… classification using AUV-based sensing, such as sidescan and synthetic aperture sonar, require an expensive payload on each outfitted vehicle and expert image interpretation. This thesis proposes a vehicle payload and machine learning classification methodology using bistatic angle dependence of …
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A model for backscattering angular response of gassy sediments: Applications to petroleum exploration and development programs
… remote sensing systems such as multibeam and sidescan sonars can be used for mapping and detection of near-surface gas in marine sediments. These systems provide a realistic depiction of the seafloor by means of the simultaneous acquisition of co-registered high-resolution bathymetry and …
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Characterization of underwater target geometry from autonomous underwater vehicle sampling of bistatic acoustic scattered fields
… classification using AUV-based sensing, such as sidescan and synthetic aperture sonar, require an expensive payload on each outfitted vehicle and expert image interpretation. This thesis proposes a vehicle payload and machine learning classification methodology using bistatic angle dependence of …
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