An Underwater Acoustic Imaging System PDF Download
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Author: Michael John Kolar
Publisher:
ISBN:
Category : Underwater acoustics
Languages : en
Pages : 126
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Book Description
An experimental underwater acoustic imaging system has been designed and built. Operating at 650 KHz, real time acoustic images are obtainable. Using both geometrical optics and Fourier optics, the theory of image formation and resolution is presented. Other factors affecting image quality and system acuity are also discussed. System components include a 650 KHz lead-zirconate-titanate (PZT) illuminating transducer, and 01.4 Plexiglas acoustic converging lens, an 81 element mosaic PZT receiving transducer which is resonant at about 650 KHz, 81 amplifiers, a scanning and synchronizing system, and a display oscilloscope. Acoustic energy reflected by the target object is collected by the lens and focused onto the image receiving transducer, which is located in the image plane. The image, appearing as a spatial acoustic pressure distribution in the image plane, is sampled by the 81 element receiver, The 81 image element voltages are amplified and sequentially transmitted to the Z-axis input of an oscilloscope. Each channel amplifier is switched, in sequence, by solid state logic switches located in the scanning circuit. The scanning circuit drives the oscilloscope in a nine line TV type raster scan. If an image element is insonified, a bright spot corresponding to the image element is lighted on the oscilloscope display. The receiving system has a measured sensitivity threshold of 3 x 10−10 watts/cm2 and a measured system resolution of approximately 2. 1°. Real time images of simple styrofoam targets are displayed.
Author: Michael John Kolar
Publisher:
ISBN:
Category : Underwater acoustics
Languages : en
Pages : 126
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Book Description
An experimental underwater acoustic imaging system has been designed and built. Operating at 650 KHz, real time acoustic images are obtainable. Using both geometrical optics and Fourier optics, the theory of image formation and resolution is presented. Other factors affecting image quality and system acuity are also discussed. System components include a 650 KHz lead-zirconate-titanate (PZT) illuminating transducer, and 01.4 Plexiglas acoustic converging lens, an 81 element mosaic PZT receiving transducer which is resonant at about 650 KHz, 81 amplifiers, a scanning and synchronizing system, and a display oscilloscope. Acoustic energy reflected by the target object is collected by the lens and focused onto the image receiving transducer, which is located in the image plane. The image, appearing as a spatial acoustic pressure distribution in the image plane, is sampled by the 81 element receiver, The 81 image element voltages are amplified and sequentially transmitted to the Z-axis input of an oscilloscope. Each channel amplifier is switched, in sequence, by solid state logic switches located in the scanning circuit. The scanning circuit drives the oscilloscope in a nine line TV type raster scan. If an image element is insonified, a bright spot corresponding to the image element is lighted on the oscilloscope display. The receiving system has a measured sensitivity threshold of 3 x 10−10 watts/cm2 and a measured system resolution of approximately 2. 1°. Real time images of simple styrofoam targets are displayed.
Author: Lowell A. Noble
Publisher:
ISBN:
Category :
Languages : en
Pages : 55
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Book Description
This report describes the results of an investigation to develop and demonstrate the feasibility of a new underwater acoustic imaging system using the HYDROCON principle. This new system would substantially extend the underwater detection capability wherever the conventional sonar and optical techniques are not applicable. The more important applications of this system would be in seeing under water over longer distances than are possible with ordinary light, especially where the degree of resolution achieved with optical vision is not needed but where it should be better than that achievable by sonar techniques. Such a system could be important for searching for lost objects under water, underwater rescue missions, piloting of submarines in mined or hazardous waters, oceanography, and classification. A breadboard system was completed and the over-all characteristics were observed experimentally. This was accomplished by using an ultrasonic transmitter, a focusing system to form the acoustic image, and a mosaic array of piezoelectric transducers connected to a specially designed image converter tube for transforming this acoustic image into a visual display. (Author).
Author: Peter Wille
Publisher: Springer Science & Business Media
ISBN: 3540279105
Category : Science
Languages : en
Pages : 504
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Book Description
Sound Images of the Ocean is the first comprehensive overview of acoustic imaging applications in the various fields of marine research, utilization, surveillance, and protection. The book employs 400 sound images of the sea floor and of processes in the sea volume, contributed by more than 120 marine experts from 22 nations.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 39
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Book Description
An innovation program to develop an underwater acoustic imaging system able to resolve objects down to millimetre resolution in turbid waters is under way. The defence need is for the identification of minelike objects. This report reviews options for the signal processing or beamforming stage of the program. An image consisting of 3x10 to the 9th power voxels (volume pixels) could be formed by a summation of the voltages from 4000 sensor elements, each taken from the element's voltage stream at the appropriate time. With a suitable allowance (factor of 9) for calculating the time delays, it appears at first sight that 9x1.2x10 to the 13th power operations would be required. The problem is to calculate a three-dimensional image of adequate quality in the shortest time at the least cost. A hierarchical structure of options is developed in an attempt to capture all possibilities. At the top level, three approaches are identified. First, the use of appropriate hardware, such as computers with parallelism. Second, a reduction in the number of operations (a software' solution). And third, the defining of a suitable reduced goal, which appears to come down to the imaging of a subvolume of the original volume that contains the object of interest. Each of these three approaches is divided into suboptions; these are discussed in detail to bring out difficulties and advantages.
Author: Richard P. Hodges
Publisher: John Wiley & Sons
ISBN: 1119957494
Category : Science
Languages : en
Pages : 386
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Book Description
Offering complete and comprehensive coverage of modern sonar spectrum system analysis, Underwater Acoustics: Analysis, Design and Performance of Sonar provides a state-of-the-art introduction to the subject and has been carefully structured to offer a much-needed update to the classic text by Urick. Expanded to included computational approaches to the topic, this book treads the line between the highly theoretical and mathematical texts and the more populist, non-mathematical books that characterize the existing literature in the field. The author compares and contrasts different techniques for sonar design, analysis and performance prediction and includes key experimental and theoretical results, pointing the reader towards further detail with extensive references. Practitioners in the field of sonar design, analysis and performance prediction as well as graduate students and researchers will appreciate this new reference as an invaluable and timely contribution to the field. Chapters include the sonar equation, radiated, self and ambient noise, active sonar sources, transmission loss, reverberation, transducers, active target strength, statistical detection theory, false alarms, contacts and targets, variability and uncertainty, modelling detections and tactical decision aids, cumulative probability of detection, tracking target motion analysis and localization, and design and evaluation of sonars
Author: Cheng Chi
Publisher: Springer
ISBN: 9811337446
Category : Technology & Engineering
Languages : en
Pages : 121
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Book Description
This book presents the topic of underwater real-time 3-D acoustical imaging covering the theory, algorithms and system design. It summarizes recent advances in wideband and ultra-wideband underwater real-time 3-D acoustical imaging, which will be very useful for developing next-generation systems. Through simulation techniques, readers are able to quickly learn and develop practical underwater real-time 3-D acoustical imaging systems of their own.
Author: Guy Ronald Arthur Vermander
Publisher:
ISBN:
Category : Computer science
Languages : en
Pages : 0
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Book Description
An algorithm has been designed to provide near real-time location and classification information to an operator of an underwater acoustic imaging system. The overall system to detect objects buried up to five meters in unconsolidated marine sediments consists of a specialized projector co-located with a five meter receiving line array. This system is described in basic terms together with the principles of the signal processing that extracts information from the scattered acoustic signals. Using simulated objects, the angular resolution and imaging performance of a number of system designs were evaluated. To obtain near real-time execution, the algorithm was optimized and partitioned using parallel, pipeline, and double buffering techniques for independent but synchronized operation on multiple microprocessors. The feasibility of the design approach was experimentally demonstrated using four single board computers in a microcomputer development system. (Author).
Author: Robert Istepanian
Publisher: Springer Science & Business Media
ISBN: 9780792373049
Category : Science
Languages : en
Pages : 298
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Book Description
Underwater Acoustic Digital Signal Processing and Communication Systems describes new design and development methodologies in underwater acoustic signal processing. The emphasis is on experimental efforts and modern DSP implementations. The book assembles a number of contributions from authors who have contributed significantly to the field. The topics cover a broad range of underwater acoustic signal processing applications: underwater wireless communciations, array processing for mapping, detection and localization of objects, biotelemetry, speech processing for divers, acoustic imaging, and use of neural networks for underwater signal processing.
Author: David Graham Blair
Publisher:
ISBN:
Category : Underwater acoustics
Languages : en
Pages : 128
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Book Description
Author: Jean-Paul Marage
Publisher: John Wiley & Sons
ISBN: 1118600657
Category : Technology & Engineering
Languages : en
Pages : 590
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Book Description
Sonar and Underwater Acoustics brings together all the concepts necessary for designers and users of sonar systems. Unlike other books on this subject, which are often too specialized, this book is accessible to a wider audience. The first part focuses on the acoustic environment, antenna structures, and electric acoustic interface. The latter provides knowledge required to design, as well as the development and implementation of chain processes for an active sonar from the conditioning input to output processing. The reader will find a comprehensive range of all problems encountered in underwater acoustics for a sonar application, from physical phenomena governing the environment and the corresponding constraints, through to the technical definition of transducers and antennas, and the types of signal processing involved. In one section, measures in underwater acoustics are also proposed.
