Search results for: ECHO
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Wizualizacja w języku VRML przemieszczania się ryb pelagicznych w wiązce echosondy.
PublicationPrzedstawiono koncepcję tworzenia wirtualnego echogramu z danych pomiarowych pochodzących z przeszukiwań akustycznych. Wykorzystując wbudowane mechanizmy języka VRML zobrazowano proces przemieszczania się ryb wraz z jednoczesną analizą echa.
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Conditions for Multiple Acquisition of Echoes from Stationary Targets in Successive Transmissions of Active Sonars
PublicationIn echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple...
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Investigation of Transmit and Receive Characteristics of Laboratory Model for the Parametric Echosounder
PublicationInvestigation and operation of devices based on nonlinear interaction of high-intensity waves have been carried out for several decades. However, it is still a new tool to study the properties of the water environment and especially the upper layers of the seabed. This paper describes the results of tests of the new device that is intended to be applied for sounding underwater areas. The device has been designed and built in collaboration with...
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Detection of Objects Buried in the Sea Bottom with the Use of Parametric Echosounder
PublicationThe paper contains results of a in situ research main task of which was to detect objects buried, partially or completely, in the sea bottom. Object detecting technologies employing acoustic wave sources based on nonlinear interaction of elastic waves require application of parametric sound sources. Detection of objects buried in the sea bottom with the use of classic hydroacoustic devices such as the sidescan sonar or multibeam...
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Three-Dimensional Echocardiography and Global Longitudinal Strain in Follow-Up After Multisystem Inflammatory Syndrome in Children
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Combined spline wavelet decomposition for 3d seafloor imaging from multibeam sonar echoes
PublicationThe paper proposes combined spline-wavelet approach to the raw echoes seaflor imaging from Multibeam Sonar System (MBSS) records. Wavelet representation is closely related to image representation, due to its unique approximations properties. Splines have the best approximation properties among all known wavelets of a given order, so they are best suited for approximating of smooth seafloor surface. Additionaly, wavelet bases have...
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Comparison of Selected Reduction Methods of Bathymetric Data Obtained by Multibeam Echosounder
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Composition of data visualizations by sub-bottom profiler and multibeam echosounder in Matlab
PublicationThis paper contains description of procedure, which was elaborated in a numerical computing environment Matlab. The result of these procedures is a graphical composition of images obtained from two different hydroacoustic devices. It enables to compare different types of visualizations for the same geographical position and simultaneous work with graphical representation of all data types.
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Określanie liczby sygnałów echa w zmodyfikowanej metodzie Prony’ego w zastosowaniu do echosondy interferometrycznej
PublicationW rozprawie zaprezentowana została analiza możliwości poprawy dokładności określania głębokości w echosondzie interferometrycznej. Analiza dostępnych źródeł wykazała, że jednym ze sposobów na osiągnięcie poprawy dokładności jest zastosowanie zaawansowanych metod określania kierunku. Spośród odstępnych metod wybrano Zmodyfikowaną Metodę Prony’ego i zastosowano ją do przetwarzania sygnałów w echosondzie interferometrycznej. Aby poprawnie...
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JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY
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Left ventricular function after takotsubo is not fully recovered in long-term follow-up: A speckle tracking echocardiography study
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Acoustic imaging of selected areas of Gdansk Bay with the aid of parametric echosounder and side-scan sonar
PublicationThe article presents and analyses the data recorded during sounding of the Gdansk Bay seabed with the aid of a parametric echosounder and a side-scan sonar. The accuracy of seabed structure examination, as a condition for obtaining valuable results, requires correct configuration of echolocation devices and proper calibration of peripheral devices, such as the survey unit geographical position sensor – GPS, the navigation unit,...
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Measurement of Seafloor Acoustic Backscatter Angular Dependence at 150 kHz Using a Multibeam Echosounder
PublicationAcoustic seafloor measurements with multibeam echosounders (MBESs) are currently often used for submarine habitat mapping, but the MBESs are usually not acoustically calibrated for backscattering strength (BBS) and cannot be used to infer absolute seafloor angular dependence. We present a study outlining the calibration and showing absolute backscattering strength values measured at a frequency of 150 kHz at around 10–20 m water...
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Multibeam Echosounder and LiDAR in Process of 360-Degree Numerical Map Production for Restricted Waters with HydroDron
PublicationIn order to increase the safety of inland navigation and facilitate the monitoring of the coastal zone of restricted waters, a model of multi-sensory fusion of data from hydroacoustic and optoelectronic systems mounted on the autonomous survey vessel HydroDron will be developed. In the research will be used the LiDAR laser scanner and multibeam echosounder. To increase the visual quality and map accuracy, additionally side scan...
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Laboratory investigation with subbottom parametric echosounder SES-2000 standard with an emphasis on reflected pure signals analysis
PublicationThe main goal of the paper is to describe correlations between measurements results of trials taken on Gulf of Gdańsk bottom sounded with parametric echosounder SES-2000 Standard and laboratory research where collected during survey sediments were measured. Stationary tests took place at Gdansk University of Technology where 30 meters long 1.8 meter deep and 3 meters wide water tank is located. Main lobe of antenna was directed...
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ECHOCARDIOGRAPHY-A JOURNAL OF CARDIOVASCULAR ULTRASOUND AND ALLIED TECHNIQUES
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Mouseion (previously: Classical Views / Echos du monde Classique)
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Time-varied-gain correction for digital echosounders. W: [CD-ROM] Forum A-custicum Sevilla 2002. 3rd European Congres on Acoustics. XXXIII Spanish Congress on Acoustics - TECNIACUSTICA 2002. European and Japanese Symposium on Acoustics. Sevilla, Spain 16-20 September 2002. Madrid: Sociedad Espano- la de Acustica**2002 vol. 33, [6 s.] 6 rys. bibliogr. 2 poz. ISBN: 84-87985-06-8 Special Issue of the Journal Revista de Acustica, vol.XXXIII, ano 2002. Korekcja zasięgowej regulacji wzmocnienia dla echosond cyfrowych.
PublicationW pracy przedstawiono modyfikację statystycznej metody EMS stosowanej w za-gadnieniach odwrotnych, polegającą na iteracyjnym rozwiązaniu równania Fred-holma. Pokazano jej zastosowanie do pośredniej estymacji siły celu ryb sto-sowanej dla danych pozyskanych przez hydrakustyczne systemy jednowiązkowewykorzystywane w przeszukiwaniach akustycznych. Wyniki porównano z rezulta-tami uzyskanymi technikami dekompozycji SVD.
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Split-beam echosounder data from Gdansk Deep Summer 2019
Open Research DataThe acoustic data was collected in 2019, in the Gdansk Deep, in the season: Summer. Data was collected during the day and night. Three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz were used to collect the data. The data was collected while the ship was sailing. To ensure data quality, echosounders were calibrated and passive...
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Split-beam echosounder data from Puck Bay autumn 2018
Open Research DataThe acoustic data was collected in 2018, in the Bay of Puck, in the seasons: autumn. Data was collected during the day and night. Three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz were used to collect the data. The data was collected at a designated study area not far from the city of Hel, while the ship was sailing. To ensure...
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Split-beam echosounder data from Puck Bay spring 2019
Open Research DataThe acoustic data was collected in 2019, in the Bay of Puck, in the season: spring. Data was collected during the day and night. Three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz were used to collect the data. The data was collected at a designated study area not far from the city of Hel, while the ship was sailing. To ensure...
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Split-beam echosounder data from Puck Bay winter 2019
Open Research DataThe acoustic data was collected in 2019, in the Bay of Puck, in the season: winter. Data was collected during the day and night. Three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz were used to collect the data. The data was collected at a designated study area not far from the city of Hel, on the route Hel - Gdynia and on...
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Echoes of the Past
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Split-beam echosounder data from Puck Bay spring 2019 Part II
Open Research DataThe acoustic data was collected in 2019, in the Bay of Puck, in the season: spring. Data was collected during the sunrise and sunset. Three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz were used to collect the data. The data was collected at a designated study area not far from the city of Hel, while the ship was sailing....
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Split-beam echosounder data from Puck Bay autumn 2018 Part II
Open Research DataThe acoustic data was collected in 2018, in the Bay of Puck, in the seasons: autumn. Data was collected during the day and night. Three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz were used to collect the data. The data was collected at a designated study area not far from the city of Hel and on the route Hel - Gdynia while...
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3d Visualization of Seabed from Multibeam Sonar Records Using TriangularIrregular Mesh. W: [CD-ROM] Forum Acusticum Sevilla 2002. 3rd European Con-gres on Acoustics. XXXIII Spanish Congress on Acoustics-TECNIACUSTICA 2002.European and Japanese Symposium on Acoustics. Sevilla, Spain 16-20 Septem- ber 2002. Madrid: Soc. Espanola de Acustica**2002 vol. 33, [6 s.] 4 rys. bibliogr. 6 poz. ISBN: 84-87985-06-8 Special Issue of the Journal Revista de Acustica, vol.33, ano 2002. Trójwym. wizual.dna mors. z danych pochodz. z echosond wielowiąz. z wykorz.niergul.siat.TIN.
PublicationPrzedstawiono sposób trójwymiarowej wizualizacji dna morskiego przy wyko-rzystaniu siatki nieregularnej (TIN) otrzymanej w wyniku triangularyzacjioraz porównano otrzymane wyniki z rzeczywistymi pomiarami batymetrycznymidna Bałtyku Południowego.
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Zespół badawczo-rozwojowy systemów hydroakustycznych
Research Teams* systemy hydroakustyczne (nawigacyjne, echolokacyjne i komunikacyjne) * przetworniki ultradźwiękowe i anteny hydroakustyczne * propagacja fal akustycznych w morzu i wodach śródlądowych * prowadzone są również prace badawcze w zakresie akustyki teoretycznej, przetwarzania sygnałów analogowych i cyfrowych i techniki ultradźwiękowej * Katedry ma bogate, wieloletnie doświadczenie w budowie systemów hydroakustycznych, poczynając od...
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A low complexity double-talk detector based on the signal envelope
PublicationA new algorithm for double-talk detection, intended for use in the acoustic echo canceller for voice communication applications, is proposed. The communication system developed by the authors required the use of a double-talk detection algorithm with low complexity and good accuracy. The authors propose an approach to doubletalk detection based on the signal envelopes. For each of three signals: the far-end speech, the microphone...
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A double-talk detector using audio watermarking
Publicationa novel approach to double-talk detection in the acoustic echo canceler is proposed. a hidden signature is embedded into the arriving signal, using the echo-hiding method. next detection of the presence of this signature in the microphone signal is performed. the results of the signature detection may be used by the acoustic echo canceler to stop or restart the adaptation process.
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Quality Evaluation of Novel DTD Algorithm Based on Audio Watermarking
PublicationEcho cancellers typically employ a doubletalk detection (DTD) algorithm in order to keep the adaptive filter from diverging in the presence of near-end speech signal or other disruptive sounds in the microphone signal. A novel doubletalk detection algorithm based on techniques similar to those used for audio signal watermarking was introduced by the authors. The application of the described DTD algorithm within acoustic echo cancellation...
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Processing data on sea bottom structure obtained by means of the parametric sounding
PublicationThe aim of the paper is to analyze data obtained during sounding the Gdansk Bay sea bed by means of the parametric echo-sounder. The accuracy of the sea bottom structure investigation needs correct configuration of research equipment and proper calibration of peripheral devices (GPS, heading sensor, MRU-Z motion sensor and navigation instruments which provide necessary data to bathymetrical measurement system, enabling its work...
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Silent Sonar with matched filtration
PublicationRadars with continuous wave frequency (CW FM sonars) are used in radiolocation as 'silent sonars'. They determine the distance to target by measuring the difference between the frequency of the sounding signal and echo signal. The article presents the principle of operation and parameters of silent CW FM sonars. Target distance determined by these sonars is based on the signal at the output of the matched filter. The Doppler effect...
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A LUMPED-CIRCUIT MODEL OF CIRCULAR PISTON TRANSDUCER FOR MODELING ITS PERFORMANCE IN DUAL FREQUENCY OPERATING MODES
PublicationThe paper presents novel network equivalent circuit of piezoceramic circular disc transducer that takes into account thickness and ra dial mode of vibrations. The starting point of the analysis is 4-port description of circular disc element representing the solution of wave equation set in radial and thickness directions. Th e approximate solution for harmonic case is represented in the form of 4x4 matrix, which is syn thesized...
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Diagnostyka zginanej płyty betonowej z zastosowaniem fal ultradźwiękowych modulowanych drganiami niskich częstotliwości
PublicationArtykuł poświęcony jest eksperymentalnej weryfikacji możliwości zastosowania modulacji diagnostycznej fali ultradźwiękowej drganiami niskich częstotliwości. Metoda jest zastosowana do wykrywania stref uszkodzenia płyty betonowej i bazuje na efektach nieliniowych wynikających z otwierania się rys. Uzyskane wyniki pozwalają na sformułowanie wniosku, że badana metoda umożliwia wykrywanie stref zarysowanych wraz z oszacowaniem ich...
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Azimuth estimator for a rotating array radar with wide beam
PublicationThe problem of estimating azimuth in rotating array radar with a beam, wide in the azimuth plane, is considered. Under such setup the echo signal usually has a very low signal to noise ratio, but the number of observations is large, because of long dwell times. The proposed solution is based on the maximum likelihood approach, but it employs simplifications which facilitate its implementation in real time systems. Results, obtained...
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The Imaging of Gdansk Bay Seabed by Using Side Sonar
PublicationThis paper is mainly aimed at presentation of an impact of environmental conditions on imaging accuracy by using hydro-acoustic systems in waters of a high non-uniformity of spatial distribution of hydrological parameters. Impact of refraction on erroneous estimation of range, in case of wave radiation into water under a large angle, like in side sonars or multi-beam echo-sounders, is especially important. In this paper seasonal...
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Time variable gain for long range sonar with chirp sounding signal
PublicationThe main purpose of applaying Time Variable Gain (TVG) in active sonars with digital signal processing is to reduce dynamic range of echo signal and adapt it to the dynamic range of the analogue to digital conversion. With high transmission losses level, the dynamic range of the input signal in long range sonars can be very high and even exceed 200dB. When chirp sounding signals with matched filtration are used, sonars can raech...
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Communication Platform for Evaluation of Transmitted Speech Quality
PublicationA voice communication system designed and implemented is described. The purpose of the presented platform was to enable a series of experiments related to the quality assessment of algorithms used in the coding and transmitting of speech. The system is equipped with tools for recording signals at each stage of processing, making it possible to subject them to subjective assessments by listening tests or, objective evaluation employing...
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The Doppler effect in a bistatic system for determining the position of moving targets
PublicationThe article presents the theoretical analysis and the results of numerical calculations of the Doppler effect it occurs in a system designed to determine the position and speed of a moving target. The transmitter is the source of the signal and it emits a sinusoidal, acoustic and continuous wave. Signal reflected off a moving target is received by four hydrophones. Based on the signals, four Doppler shifts are determined and inserted...
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Underwater Navigation System Based on Doppler Shifts of a Continuous Wave
PublicationThe paper describes a concept of an underwater navigation system designed to determine the location and speed of its ROVs or divers. Conducted by the Department of Marine Electronic Systems at the Gdansk University of Technology for several years, research has focused on navigation systems which determine positions on the basis of Doppler shifts of echo signals reflected from a moving object. This article presents a different version...
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Opracowanie opinii technicznej w zakresie występowania iniektu wewnątrz wskazanych przez Zleceniodawcę kanałów kablowych mostu MA-09 w ciągu drogi S7
PublicationCelem opracowania jest ocena występowania iniektu wewnątrz wskazanych przez Zleceniodawcę kanałów kablowych mostu MA-09 realizowanego w ramach zadania „Budowa drogi S-7 Gdańsk (A-1) – Elbląg (S-22) odc. Koszwały (DK nr 7, W. Koszwały) - Elbląg (z węzłem Kazimierzowo) z podziałem na 2 części. Zadanie 1: Koszwały – Nowy Dwór Gdański“. Zakres opracowania obejmuje: • zapoznanie się z dokumentacją techniczną obiektu, • wizję lokalną, •...
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Multibeam sonar data processing for seafloor characterisation
PublicationThe approach to seafloor characterisation was investigated. It relies on calculation of several descriptors (parameters) related to seabed type using three types of multibeam sonar data obtained during seafloor sensing: 1) the grey-level sonar images of seabed, 2) the 3D model of the seabed surface which consist of (x, y, z) points, 3) the set of time domain echo envelopes corresponding to several beams. The proposed method has...
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Combined method of multibeam sonar signal processing and image analysis for seafloor classification
PublicationThe combined approach to seafloor characterisation was investigated. It relies on calculation of several descriptors (parameters) related to seabed type using three types of multibeam sonar data obtained during seafloor sensing: 1) the grey-level sonar images (echograms) of seabed, 2) the 3D model of the seabed surface which consists of bathymetric data, 3) the set of time domain bottom echo envelopes received in the consecutive...
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Application of Maximum Lenght Sequence in Silent Sonar
PublicationSilent sonars are designed to reduce the distance over which their sounding pulses can be detected by intercept sonars. In order to meet this objective, we can use periodical sounding signals that have low power, a very long duration and wide spectrum. If used in the silent sonar's receiver, matched filtration ensures very good detection of motionless or slow moving targets. However, it is more difficult to detect echo signals...
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System for characterisation and multidimensional imaging of seafloor using multibeam sonar data
PublicationMultibeam sonars are widely used in applications like high resolution bathymetry measurements, underwater object detection and imaging, etc. Also, they are the promising tool in seafloor characterisation and classification, having several advantages over conventional single beam echosounders. The proposed approach to seafloor classification relies on the combined use of three different techniques. In each of them, a set of descriptors...
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On Algorithm Details in Multibeam Seafloor Classification
PublicationRemote sensing of the seafloor constitutes an important topic in exploration, management, protection and other investigations of the marine environment. In the paper, a combined approach to seafloor characterisation is presented. It relies on calculation of several descriptors related to seabed type using three different types of multibeam sonar data obtained during seafloor sensing, viz.: 1) the grey-level sonar images (echograms)...
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Using Principal Component Analysis and Canonical Discriminant Analysis for multibeam seafloor characterisation data
PublicationThe paper presents the seafloor characterisation based on multibeam sonar data. It relies on using the integrated model and description of three types of multibeam data obtained during seafloor sensing: 1) the grey-level sonar images (echograms) of seabed, 2) the 3D model of the seabed surface which consists of bathymetric data, 3) the set of time domain bottom echo envelopes received in the consecutive sonar beams. The classification...
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Diagnostyka ultradźwiękowa mostowej belki prefabrykowanej typu T metodą młoteczkową
PublicationZastosowanie prefabrykacji w budowie obiektów mostowych pozwala optymalizować zużycie energii i materiałów i tym samym redukować koszty budowanego obiektu. Prefabrykowane belki sprężone mogą występować jako elementy kablobetonowe wykonywane bezpośrednio na placu budowy lub powstawać w zakładzie prefabrykacji jako elementy strunobetonowe. Elementy prefabrykowane wytwarzane w warunkach przemysłowych muszą spełniać wymagania wysokiej trwałości,...
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Computer vision techniques applied for reconstruction of seafloor 3D images from side scan and synthetic aperture sonars data
PublicationThe Side Scan Sonar and Synthetic Aperture Sonar are well known echo signal processing technologies that produce 2D images of the seafloor. Both systems combines a number of acoustic pings to form a high resolution image of seafloor. It was shown in numerous papers that 2D images acquired by such systems can be transformed into 3D models of seafloor surface by algorithmic approach using intensity information, contained in a grayscaled...
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Seafloor Characterisation Using Underwater Acoustic Devices
PublicationThe problem of seafloor characterisation is important in the context of management as well as investigation and protection of the marine environment. In the first part of the paper, a review of underwater acoustic technology and methodology used in seafloor characterisation is presented. It consists of the techniques based on the use of singlebeam echosounders and seismic sources, along with those developed for the use of sidescan...