Download or read book Automatic Detection and Tracking of Fish Shoals Over Large Areas Using Ocean Acoustic Waveguide Remote Sensing OAWRS written by Felix Piavsky and published by . This book was released on 2021 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurately tracking multiple fish shoals can help understand fish migration patterns, better estimate fish populations, and lead to better decisions regarding fishery routines and preservation of the related marine ecosystems. Previously, fish shoals and their characteristics were identified manually for each shoal. Here we present techniques to automatically detect, track, and predict small fish shoal characteristics using Ocean Acoustic Waveguide Remote Sensing (OAWRS) over large areas and extended time periods. OAWRS system allows us to instantaneously map, image, and monitor fish populations over continental shelf-scale areas of thousands of square kilometers. Conventional fishery sonars operate at much higher frequencies and so have detection ranges limited the immediate vicinity of research vessels. The methods presented here can provide near real-time analysis during experiments or later analysis. In this work, we continuously tracked the migration of multiple fish schools during the 2014 Norwegian Sea experiment and 2003 Atlantic US coast experiment. Each shoal goes through image processing, tracking, feature extraction, and track management analysis. We take into account special cases such as splitting or merging of shoals. The results of this work can provide reliable tracking of small fish shoals, marine mammals, and underwater vehicles.

Download or read book Spectral Discrimination of Fish Shoals from Seafloor in the Gulf of Maine During the Ocean Acoustic Waveguide Remote Sensing OAWRS 2006 Experiment written by Eleftherios Kaklamanis and published by . This book was released on 2021 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we perform a spectral discrimination of fish shoals from background returns using statistical techniques. Classification of fish species requires an efficient and solid approach to distinguish fish scattering from seafloor returns. Neyman-Pearson Hypothesis Testing, Kullback-Leibler divergence, Matched Filter and discriminating based on the shape of the spectral dependence, methods originated from Detection theory, are applied in well documented cases from Gulf of Maine during spawning season to distinguish seafloor returns from fish scattering across frequency domain. The discrimination of fish shoals from seafloor returns is achieved by analyzing the absolute levels of scattered returns and the pattern of their frequency response. A generalization of the statistical techniques is developed that enables all frequencies to be tested at once, allowing the spectral discrimination and echolocation of fish shoals from regions dominated by background returns. Conclusions derived from statistical techniques are consistent with physical evidences, such as in situ echosounder measurements and frequency responses. Fish shoals are distinguished from background regions by evaluating the likelihood ratio test, matched filter and analyzing the slope of the frequency dependence of all pixels in an examined ocean acoustic waveguide remote sensing (OAWRS) image.

Download or read book Continuous Monitoring of Fish Population and Behavior by Instantaneous Continental Shelf Scale Imaging with Ocean Waveguide Acoustics written by and published by . This book was released on 2007 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term goals of this program are to (1) instantaneously detect, image and spatially chart fish populations over continental-shelf scales, and (2) continuously monitor the areal densities and behavior of these fish populations over time using a novel audible frequency acoustic system (300- 5000Hz) referred to as Ocean Acoustic Waveguide Remote Sensing (OAWRS). This new method is being applied to explore the abundance, temporal and spatial distributions and behavior of fish populations in the Gulf of Maine on and near Georges Bank, a marine ecosystem being studied in the Census of Marine Life program. OAWRS is a valuable conservation tool for rapid imaging and enumeration of large scale fish populations over thousands of square kilometers to effectively monitor and manage the national fish stock.

Download or read book Acoustic Clutter and Ocean Acoustic Waveguide Remote Sensing OAWRS in Continental Shelf Environments written by and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic clutter is the primary problem encountered by active sonar systems operating in Continental Shelf environments. Clutter is defined as any return from the environment that stands prominently above the diffuse and temporally decaying reverberation background and so can be confused with or camouflage returns from an intended target such as an underwater vehicle. Many environmental factors may contribute to acoustic clutter and adversely affect the performance of tactical Navy sonar by introducing false alarms in the system. In order to develop adaptive algorithms or technology to mitigate acoustic clutter, it is critical to identify, understand, and be able to accurately model the leading order physical mechanisms which cause clutter in existing sonar systems. The long-term goal of this program is to determine and understand the physical mechanisms that cause acoustic clutter in continental shelf environments and to use this knowledge to develop predictive tools to enhance the detection, localization and classification of underwater targets.

Download or read book Enabling High Resolution Population Density Imaging of Random Scatterer Groups in a Fluctuating Range dependent Ocean Waveguide with the Matched Filter Variance written by Mark Andrews and published by . This book was released on 2010 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Underwater acoustic imaging and surveillance systems often transmit broadband pulses and process the scattered returns with a correlation matched filter in order to achieve high spatial resolution in range localization. When imaging distributed groups of scatterers, such as schools or shoals of fish, bubble clouds and swarms of AUVs, large numbers of individuals, ranging from tens to hundreds of thousands, are often present within each resolution cell of the imaging system. To estimate population density, spatial distribution, scattering cross-section and other parameters of the scatterer group and their error bounds, it is essential to understand the statistical nature and composition of the broadband matched filtered scattered returns. Here, using a combination of theoretical model development and experimental data analysis, we investigate (1) the statistics of broadband acoustic propagation in temporally and spatially varying shallow water waveguides, (2) the statistics and mechanisms for scattering from distributed groups, and (3) the effects of multiple scattering and waveguide dispersion in predicting the level and duration of the broadband matched filtered scattered intensities. The analysis is applied to two types of underwater acoustic imaging systems for mapping fish distributions. (a) The ocean acoustic waveguide remote sensing (OAWRS) system that allows instantaneous wide area continental-shelf scale imaging by utilizing muti-modal waveguide propagation, and (b) the conventional ultrasonic echosounder using direct-path propagation to image scatterer groups over water depth.Using experimental data acquired in the US east coast continental shelf, the scintillation statistics of one-way propagated broadband waveforms are quantified as a function of signal bandwidth, center frequency, and range. The received broadband intensity is shown to follow the Gamma distribution implying the central limit theorem has led to a fully saturated Gaussian field. An efficient numerical approach is developed to estimate the broadband transmission loss in a fluctuating, range-dependent ocean waveguide using spatial averaging of a time-harmonic stochastic propagation model. This approach is essential for rapidly detrending OAWRS imagery to make real time population density estimates.Theoretical models are then developed to determine the statistical moments of the broadband matched filtered scattered returns from distributed groups. For the ultrasonic echosounder, a numerical Monte-Carlo model that includes multiple scattering is developed and implemented to determine the conditions for when multiple scattering is significant. The model is implemented for Atlantic herring schools found in the Gulf of Maine, imaged with a conventional fisheries echosounder. Our analysis indicates that the single-scatter approximation is valid even for dense Atlantic herring schools at ultrasound frequencies. For direct-path imaging systems, an analytic model is also developed to efficiently estimate the scattered field statistics from the group by applying a single scatter approximation. The model can be used to compare the levels of the coherently and incoherently scattered intensities. It provides an explanation for how high spatial resolution is acheived with incoherently scattered fields with the coherent matched filter.We examine the effects of multiple scattering, attenuation, and waveguide dispersion on population density imaging with the OAWRS imaging system by implementing a numerical Monte-Carlo model. The model determines the statistical moments of the matched filtered multiply scattered returns from a distributed group of discrete scatterers, and incorporates propagation through a fluctuating range-dependent ocean environment. Results of the model are applied to interpret OAWRS imagery of shoaling Atlantic herring populations acquired during the NOPP-funded 2006 Experiment in the Gulf of Maine. Our analysis indicates that multiple scattering and attenuation were mostly negligible at OAWRS frequencies employed and for herring densities observed.

Download or read book Application of Remote Sensing Methods for Tracking Large Cetaceans written by and published by . This book was released on 1992 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanic Internal Waves from Ship Aircraft and Spacecraft written by Atlantic Oceanographic and Meteorological Laboratory. Ocean Remote Sensing Laboratory and published by . This book was released on 1978 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanic Internal Waves from Ship Aircraft and Spacecraft written by Atlantic Oceanographic and Meteorological Laboratories. Ocean Remote Sensing Laboratory and published by . This book was released on 1978 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ocean Remote Sensing Laboratory (ORSL) has been studying internal waves using remote sensing techniques employing three different types of observational platforms: ships, aircraft, and spacecraft. Internal waves and their manifestations have been observed using the following techniques: Satellite multispectral scanning imagers (principally in the visible and near-infrared); Radar--both coherent imaging radar and standard meteorological radar (all from aircraft); Hand-held visible photography (from spacecraft, aircraft, and ship; Ship-towed thermistors; and STD and XBT casts.

Download or read book Coastal Remote Sensing written by Coastal Services Center (U.S.) and published by . This book was released on 2003 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Remote Sensing of Shelf Sea Hydrodynamics written by J.C.J. Nihoul and published by Elsevier. This book was released on 2000-04-01 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remote Sensing of Shelf Sea Hydrodynamics

Download or read book Acoustic Fish Reconnaissance written by I.L. Kalikhman and published by CRC Press. This book was released on 2006-03-21 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Until now, there has not been any work that systematically presents the subject of acoustic fish reconnaissance, details all major aspects of applying acoustic equipment in commercial fish reconnaissance, and offers sufficient analysis of the effectiveness of fish-finding techniques. Acoustic Fish Reconnaissance responds to this need by providing the first overview of the theoretical and practical aspects of acoustic search, detection, interpretation, and population estimation for commercial benefit. This book pays particular attention to the theory and practice of accounting surveys for quantitative estimation of biological resources and fishing conditions in traditional fishing areas. It also analyzes various applications of acoustic technique, based upon the authors' extensive investigations. The text includes the results of the applicability of fish-finding instruments, and offers recommendations on the development of improved acoustic techniques for commercial fleets.

Download or read book Implantable Acoustic beacon Automatic Fish tracking System written by Robert J. Mayhue and published by . This book was released on 1977 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Acoustic Techniques for Assessing Fish Schooling in the Context of an Operational Ocean Observatory written by and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this work is to develop new methods for observing large spatial scales in oceanic ecosystems. In particular, this report focuses on the development and use of a new type of mid-frequency, multi-beam sonar for making long-range backscatter images of fish aggregations in shallow water with the aid of the ocean acoustic waveguide. Fish aggregation is important during spawning, predation, and feeding, yet the quantitative analyses of gregarious movements and behaviors remain relatively rare. Measurements of fish aggregations are often difficult, particularly in pelagic environments. In terms of the forward sonar problem, widespread fish aggregations will appear as interfering reverberation, while schools and shoals may appear as false targets or may screen other targets, degrading sonar system performance.

Download or read book Passive Microwave Remote Sensing of Oceans written by Igor V. Cherny and published by . This book was released on 1998-07-14 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Passive Microwave Remote Sensing of Oceans Igor V. Cherny and Victor Yu. Raizer In Passive Microwave Remote Sensing of Oceans, the detailed results of more than 20 years of experimental and theoretical investigations in the field of ocean remote sensing, utilising microwave radiometric techniques and multi-frequency aerospace instruments, are presented. Experimental results presented in this book to some extent contradict the traditional view that microwave radiometry and, in particular, millimetre-wave frequencies are not useful for remote sensing of oceans. The authors show that studies of the ocean and atmosphere as a coupled system, and of processes occurring at the ocean surface and in deep water, can be reliably evolved using compact passive radiometric sensors. They further demonstrate that for studies of global, large-scale and local processes in the ocean-atmosphere system, only the combination of microwave and optical techniques will reveal the spatial structure and dynamics of the ocean surface at scales from centimetres to several hundred metres. The text first introduces ocean surface phenomena, discussing the ocean-atmosphere interface, the classification of surface waves, the generation and statistics of wind waves, and wave-breaking and foaming processes. The microwave emission characteristics of the ocean surface are then described, and the influence of wind waves, bubble-foam-spray coverage, oil spills and sea ice are discussed. The instruments and methods used for passive microwave remote sensing of the oceans from both aircraft and from satellites are reviewed. Microwave observations of processes in the ocean-atmosphere system are then described in detail, incorporating a new approach for microwave diagnostics of deep-ocean processes. Examples presented include the Rossby soliton, frontal zone in the Kurosio region, influence of brief showers on the subsurface layer, and interaction of tropical cyclones with the ocean during their origin and subsequent trajectories over the ocean surface. Readership: Undergraduate and postgraduate students studying remote sensing, marine science, oceanography, geography, geophysics, meteorology, climatology, atmospheric physics and environmental science. Professional oceanographers and those interested in oceanographic remote sensing processes and their applications, marine scientists and engineers, environmental scientists, and those studying the ocean-atmosphere system.

Download or read book Ocean Sensing and Monitoring written by Weilin Hou and published by SPIE-International Society for Optical Engineering. This book was released on 2013-01-01 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an introductory text that presents the major optical ocean sensing techniques. It is suitable for professionals and managers in related disciplines, as well as students who are interested in exploring career paths in remote sensing of the ocean or ocean engineering.

Download or read book Ocean Remote Sensing with Synthetic Aperture Radar written by and published by Mdpi AG. This book was released on 2018-01-25 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean covers approximately 71% of the Earth's surface, 90% of the biosphere and contains 97% of Earth's water. The Synthetic Aperture Radar (SAR) can image the ocean surface in all weather conditions and day or night. SAR remote sensing on ocean and coastal monitoring has become a research hotspot in geoscience and remote sensing. This book--Progress in SAR Oceanography--provides an update of the current state of the science on ocean remote sensing with SAR. Overall, the book presents a variety of marine applications, such as, oceanic surface and internal waves, wind, bathymetry, oil spill, coastline and intertidal zone classification, ship and other man-made objects' detection, as well as remotely sensed data assimilation. The book is aimed at a wide audience, ranging from graduate students, university teachers and working scientists to policy makers and managers. Efforts have been made to highlight general principles as well as the state-of-the-art technologies in the field of SAR Oceanography.

Download or read book Breaking Ocean Waves written by Eugene A. Sharkov and published by Springer. This book was released on 2007-07-30 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eugene Sharkov, of the Space Research Institute in Moscow, has here put together the most comprehensive description of the physical findings of an investigation into the spatio-temporal characteristics of the gravity of breaking waves. He’s also described the foam activity in the open sea using methods and instruments of optical and microwave remote sensing. Numerous practical applications and illustrations are provided from air-borne, ship-borne and laboratory up-to-date experiments.