Download or read book Towards Real time Sea floor Surface Reconstruction and Classification Using 3 D Side scan Sonar written by Ryan Michael Goldade and published by . This book was released on 2014 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a computer algorithm to solve two major hurdles for generating real-time automated sea-floor maps with composition classification using 3-D side-scan sonar data. The algorithm consists of two distinct parts: sea-floor profiling and sea-flooring classification with computation acceleration from a graphics processing unit (GPU). The sea-floor profiling algorithm is an automated method that identifies bathymetry data corresponding to the sea-floor while ignoring bathymetry corresponding to water column objects and multi-path returns. The algorithm improves upon a fuzzy curve tracing method to handle discontinuities in the point-cloud data along the sea-floor and to discriminate between the sea-floor and other data. With an average error of 2.6% and a computation time of 7.40ms, the sea-floor profiling algorithm is extremely accurate and efficient. Classification of the sea-floor regions consists of applying image texture methods and machine learning classifiers to side-scan sonar images. In this thesis, a feature space for each side-scan sonar image pixel is created using image texture analysis algorithms, and classified with an artificial neural network. The accuracy and performance of the algorithm is tested with side-scan sonar images from the Underwater Research Lab's Pam Rocks sonar survey. Real-time classification was achieved by the use of GPU computing. Porting the algorithm onto the GPU using OpenCL reduced the per-ping computation time to an average of 100ms, with an average error of 3.4%, making it a viable real-time solution in a sonar system.
Download or read book A Comparison of Seafloor Sonar Classification Methods Through the Use of Error Matrices and 3 Dimensional GIS Visualization written by Andrew S. Lanier and published by . This book was released on 2006 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multibeam sonar data was collected on Nehalem Bank, off of the Oregon Coast with the purpose of increasing the spatial resolution of our knowledge of the area and delineating seafloor habitats. The system used was the Kongsberg Simrad EM-300 operating at 30 kHz. The data set collected includes both topographic and backscatter information, both of which were processed and gridded at a 5m cell-size resolution. This thesis summarizes the methods used in the characterization of seafloor habitat using the Nehalem Bank data and the analysis tools incorporated within a geographic information system (GIS). This work focuses on investigations into the analysis of benthic habitats through the use of algorithmic calculations at multiple scales to quantitatively delineate distinct seafloor regions. A recently developed spatial analysis technique, the bathymetric position index (BPI), was tested and used as part of the Benthic Terrain Modeler Tool to classify the Nehalem Bank data. Those results were compared both qualitatively and quantitatively to a newly developed method (developed for this project) entitled the surface interpretation method (SIM). Both methods of classification use multiple scales of BPI in conjunction with the topographic digital elevation model (DEM) to quantitatively delineate seafloor habitats. While accuracy assessments of remotely sensed imagery on land are usually carried out using groundtruthing information collected specifically for that purpose, sonar imagery is often assessed using any information available. The groundtruth data available for Nehalem Bank is sparsely located throughout the region and includes: submersible dives, sample data, and seismic and sidescan imagery. In order to evaluate the fit of the classification attempts to the DEM quantitatively, a set of reference points was created and interpreted using the three dimensional (3D) visualization capabilities of a GIS. The results were analyzed using error matrix statistical measures that provided a quantitative assessment of the classification results, the feedback from which guided a refinement of the classification methods. This was done in attempt to optimize "real-world" evaluation of a classification methods results, without an idealized level of seafloor groundtruth data. The backscatter component of the data was processed to reduce the influence of grazing angle on the intensity of surface returns, a common source of noise that dominates many datasets. The processed image shows a reduced variability of the grey level of the imagery in both along and across track directions. Submersible dive groundtruth data were then co-located with the backscatter imagery using habitat interpretations of the dives displayed upon the DEM. The backscatter data was then classified in the regions of the dives using textural analysis with grey level co-occurrence matrix derived indices of homogeneity and entropy. The resulting substrate class divisions satisfactorily parsed the landscape into habitat regions, with the exceptions of the nadir and shadow regions. However, higher frequency deep-towed sidescan imagery in the same region shows that the delineation of substrate regions appears to be incorrect with the EM300 imagery likely imaging subsurface seafloor characteristics.
Download or read book Oceans 2002 written by Oceans and published by . This book was released on 2002 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Seafloor Sonar Imagery written by Philippe Blondel and published by . This book was released on 1997-05-30 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the ocean floor remains unmapped but with the introduction of acoustic remote sensing and deep submersible dives this is now achievable. The major use of this book is interpretation of sonar images through worked examples.
Download or read book Underwater Acoustic Digital Signal Processing and Communication Systems written by Robert Istepanian and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater acoustic digital signal processing and communications is an area of applied research that has witnessed major advances over the past decade. Rapid developments in this area were made possible by the use of powerful digital signal processors (DSPs) whose speed, computational power and portability allowed efficient implementation of complex signal processing algorithms and experimental demonstration of their performance in a variety of underwater environments. The early results served as a motivation for the development of new and improved signal processing methods for underwater applications, which today range from classical of autonomous underwater vehicles and sonar signal processing, to remote control underwater wireless communications. This book presents the diverse areas of underwater acoustic signal processing and communication systems through a collection of contributions from prominent researchers in these areas. Their results, both new and those published over the past few years, have been assembled to provide what we hope is a comprehensive overview of the recent developments in the field. The book is intended for a general audience of researchers, engineers and students working in the areas of underwater acoustic signal processing. It requires the reader to have a basic understanding of the digital signal processing concepts. Each topic is treated from a theoretical perspective, followed by practical implementation details. We hope that the book can serve both as a study text and an academic reference.
Download or read book Forward Scan 2 D Sonar Image Formation and 3 D Reconstruction written by Murat D Aykin and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interpretation of acoustical images to understand the characteristics of a scene and identify under-water objects has become a problem of high importance in a variety of applications. In the meantime, the computer processing of forward-scan sonar video imagery has enabled significant capabilities in a wide variety of underwater operations within turbid environments. Further developments are inevitable with more accurate representation of the image formation principles of these sonars. Sonar images are formed by transmitting acoustical pulses and measuring the reflected sound power from the scene surfaces. The recorded signal encodes information about the shape and material properties of these surfaces. The inherent ambiguities in the interpretation of the 3-D world based on visual cues in a 2-D forward-scan sonar image arise as a result of both operating as a ranging device and loss of elevation angle information due to the projection geometry. One aspect of this work is modeling the image formed by a new class of high-resolution 2-D forward-scan sonar systems which supports our complementary aim of simulating FL sonar images. The other aspect is reconstructing 3-D objects by either recovering the unknown zenith angles from image brightness of a single sonar view or by applying a carving based technique on multiple sonar views. To elaborate, we first provide a detailed derivation for modeling the image formed by a forward-scan sonar. Our initial model derived for a small surface patch is generalized to handle multiple patches and account for the signal type and pulse-width. We exemplify and simulate our model for a circular target profile and validate it by comparing with the true intensities measured from two isolated cylindrical targets with circular cut sections. Then we demonstrate application of our model for multi-path reflections from bottom surfaces with hemi-cylindrical and hemi-spherical targets laid on the bottom. Next, we propose a method to recover the unknown zenith angles from image brightness and thus reconstruct 3-D objects. Our method applies to a single forward-scan sonar image, assuming that the scene objects have smooth surfaces that vary monotonically in terms of distance from the sonar, and cast visible shadows on a flat background. We present the results of experiments with real data to demonstrate the performance of our 3-D reconstruction technique. Finally, we develop a method for determining the 3-D shape of a target from multiple 2-D forward-scan sonar images at given sonar poses. Our strategy is based on sequentially carving the non-target space projecting onto the so-called dark pixels on various images. We demonstrate how the remaining space, deemed to be occupied by the target, approaches toward the object volume, given enough views. The images acquired through sonar roll motions, rather than circumnavigating the target, are critical for more precise reconstruction. Employing our image simulator, we perform extensive tests to assess the convergence properties of our 3-D approach for convex and concave polygons. Further experiments with real data, collected by DIDSON, ARIS, and Blueview sonars demonstrate the performance from image sequences of four amorphous coral rocks and a wooden table. Potential applications of our techniques include target localization and re-acquisition, classification and recognition, obstacle avoidance and precision navigation, scene mapping in support of studying underwater ecosystems, and investigation of deep-water archaeological sites within turbid environments.
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sonar Systems written by Nikolai Kolev and published by IntechOpen. This book was released on 2011-09-12 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is an edited collection of research articles covering the current state of sonar systems, the signal processing methods and their applications prepared by experts in the field. The first section is dedicated to the theory and applications of innovative synthetic aperture, interferometric, multistatic sonars and modeling and simulation. Special section in the book is dedicated to sonar signal processing methods covering: passive sonar array beamforming, direction of arrival estimation, signal detection and classification using DEMON and LOFAR principles, adaptive matched field signal processing. The image processing techniques include: image denoising, detection and classification of artificial mine like objects and application of hidden Markov model and artificial neural networks for signal classification. The biology applications include the analysis of biosonar capabilities and underwater sound influence on human hearing. The marine science applications include fish species target strength modeling, identification and discrimination from bottom scattering and pelagic biomass neural network estimation methods. Marine geology has place in the book with geomorphological parameters estimation from side scan sonar images. The book will be interesting not only for specialists in the area but also for readers as a guide in sonar systems principles of operation, signal processing methods and marine applications.
Download or read book Real Time Segmentation and Classification of Side Scan Sonar Images written by Mahesh Khidkikar and published by . This book was released on 2012 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Petroleum Abstracts written by and published by . This book was released on 1996 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Science Abstracts written by and published by . This book was released on 1995 with total page 1360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earth Resources written by and published by . This book was released on 1986 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Report to the President written by United States. Presidential Commission on the Space Shuttle Challenger Accident and published by . This book was released on 1986 with total page 1316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to IEEE Publications written by Institute of Electrical and Electronics Engineers and published by . This book was released on 1996 with total page 1260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues for 1973- cover the entire IEEE technical literature.
Download or read book UnderWater written by and published by . This book was released on 2000 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atlas of Submarine Glacial Landforms written by J.A. Dowdeswell and published by Geological Society of London. This book was released on 2016-12-16 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: New geophysical techniques (multibeam echo sounding and 3D seismics) have revolutionized high-resolution imaging of the modern seafloor and palaeo-shelf surfaces in Arctic and Antarctic waters, generating vast quantities of data and novel insights into sedimentary architecture and past environmental conditions. The Atlas of Submarine Glacial Landforms is a comprehensive and timely summary of the current state of knowledge of these high-latitude glacier-influenced systems. The Atlas presents over 180 contributions describing, illustrating and discussing the full variability of landforms found on the high-latitude glacier-influenced seafloor, from fjords and continental shelves to the continental slope, rise and deep-sea basins beyond. The distribution and geometry of these submarine landforms provide key information on past ice-sheet extent and the direction and nature of ice flow and dynamics. The papers discuss individual seafloor landforms, landform assemblages and entire landsystems from relatively mild to extreme glacimarine climatic settings and on timescales from the modern margins of tidewater glaciers, through Quaternary examples to ancient glaciations in the Late Ordovician.
Download or read book Jane s International Defense Review written by and published by . This book was released on 2005 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
