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Wyszukujesz frazę "Łubniewski, Z." wg kryterium: Autor

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    Wyświetlanie 1-7 z 7
    Tytuł:
    Modelling the seafloor 3D relief and its reconstruction from multibeam sonar data
    Autorzy:
    Łubniewski, Z.
    Moszyński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/331622.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Opis:
    The simple, real-time procedure for seafloor relief reconstruction and simultaneous seabed type identification using echo data from hypothetical multibeam sonar system was proposed. The algorithm was tested using artificially generated relief and seabed type data. In the first stage, 3D surface of seafloor was generated, using the inverse Fourier transformation of the 2D spatial frequency spectrum of power law form. In the second stage, the generation. of the set of multibeam sonar data, which simulated echoes collected from seabed, was performed with account for the distances from transducer to particular surface elements, scattering coefficient and the angles of insonification. Finally, the spatial form of seabed was reconstructed using the simulated data, while bottom type was identified simultaneously using estimated angular dependence of backscattering coefficient. The obtained results showed the good performance of the proposed reconstruction procedure for artificial data and suggested verification of the algorithm using real data.
    Źródło:
    Hydroacoustics; 2001, 4; 153-156
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelowanie odpowiedzi impulsowej dla rozpraszania wstecznego dna morskiego
    Modelling of the impulse response for backscattering from seafloor
    Autorzy:
    Łubniewski, Z.
    Moszyński, M.
    Stepnowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/332215.pdf
    Data publikacji:
    2000
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Opis:
    The modelling of surface and volume backscattering of a single-beam echosounder signals on sea fioor using impulse response approach is presented. Kirchhoff (tangent plane) approximation is used in surface scattering modelling for approximately fiat sea bottom and smal! perturbation theory is applied to describe the volume backscattering. The influence of bottom physical features as well as the system parameters (operating frequency, beamwidth) on the shape of the sea bed impulse response and echo waveform is investigated. The results have revealed the differences for particular cases of bottom and acoustic system 's parameters and they are important for validation of newly developed algorithms of echo signals processing for bottom classification.
    Źródło:
    Hydroacoustics; 2000, 3; 35-38
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of inverse filtering techniques in the sea bottom recognition
    Autorzy:
    Łubniewski, Z.
    Moszyński, M.
    Stepnowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/332346.pdf
    Data publikacji:
    1999
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Opis:
    The paper presents the newly developed approach to the sea bottom recognition and identification, which uses inverse filtering techniques to extract bottom scattering properties from a single-beam echosounder signal. Using simple physical model, the developed inverting procedure allows to remove the influence of pulse shape, beam pattern and model geometry upon the backscattered echo. 11permits to obtain the seabed impulse response which is directly related to the function describing the angular dependence of bottom reverberation coefficient. Various direct and iterative inverse methods can be applied to the mentioned problem. The results of testing the method using echoes from several bottom types are in agreement with the predictions of theoretical models. Moreover, the proposed bottom classification procedure uses simple parameters of deconvolved function and the obtained classification results are better than those of ofher bottom identification methods of normal incidence.
    Źródło:
    Hydroacoustics; 1999, 2; 95-100
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Using wavelet techniques for multibeam sonar bathymetry data compression
    Autorzy:
    Chybicki, A.
    Łubniewski, Z.
    Moszyński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/331892.pdf
    Data publikacji:
    2010
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Opis:
    Multibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on the autonomous underwater vehicle operating on large depths and transmitting the data to the operator station using acoustic channel. In this context, the authors propose a method for multibeam sonar data size reduction. It relies on the use of wavelet decomposition technique combined with run-length and Huffman coding. The method was applied for lossy compression of raw bathymetry data which had been generated by a multibeam sonar processing unit in a form of a set of points in three-dimensional space. The performed tests revealed that without introducing the substantial distortion into the processed bathymetry data, the proposed approach allows to obtain better compression ratios than in the case of using standard lossy JPEG-like compression techniques.
    Źródło:
    Hydroacoustics; 2010, 13; 31-38
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multi-frequency analysis of seabed echoes using wavelet transform
    Autorzy:
    Moszyński, M.
    Stepnowski, A.
    Łubniewski, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/332256.pdf
    Data publikacji:
    1999
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Opis:
    The methods based on analysis of boftom backscatter data from a single-beam echosounder have achieved special attention in the seabed identification problem. due to their simplicity over ofher more sophisticated acoustic techniques like side scan sonar or multibeam surveys. The majority of these methods analyses the scattering phenomena mostly in time domain (echo envelope). However, the frequency echo components carry concurrent information, which can be also used in boftom characterisation. The paper proposes the time-frequency approach to the boftom characterisation and presents the application of Wigner- Ville Distribution and wavelet transform of boftom backscatter data. The examples of continuous and discrete wavelet transforms of actual echo envelopes received at three boftom types for three different operating frequencies (38, 120 and 420 kHz) are shown. Their characteristic features are compared and parameters for classification schemes are proposed. The results of classification procedure are good with comparison with those of ofher simple acoustic methods.
    Źródło:
    Hydroacoustics; 1999, 2; 85-90
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reconstruction of 3D shape from sidescan sonar images using shape from shading technique
    Autorzy:
    Moszyński, M.
    Bikonis, K.
    Łubniewski, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/332701.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Opis:
    Side scan sonar (SSS) is one of the most widely used imaging systems in the underwater environment. It is relatively cheap and easy to deploy in comparison with more powerful sensors like multibeam echosounder or synthetic aperture sonar. Although, the SSS does not provide directly the seafloor bathymetry measurements. Its outputs are usually in a form of grey level acoustic images of seafloor. However, the analysis of such images performed by human eye allows creating semi-spatial impressions on seafloor relief and morphology. The 3D shape reconstruction from 2D images using SFS approach is one of classical problems in computer vision. In the paper, the method based on Shape From Shading (SFS) technique for SSS images processing is presented. The 3D seafloor relief is reconstructed using the information from both the currently processed and previous ping. The seafloor backscattering coefficient dependence on an incident angle, which is needed in the applied SFS algorithm scheme, is being estimated in the experimental way, i.e. by analysis of SSS image contents for the flat seabed region.
    Źródło:
    Hydroacoustics; 2013, 16; 181-188
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Geographic information system for remote integration of diverse under-water acoustic sensor data
    Autorzy:
    Chybicki, A.
    Kamiński, Ł.
    Lubniewski, Z.
    Bruniecki, K.
    Kulawiak, M.
    Dąbrowski, J.
    Moszyński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/332542.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    geographic information system (GIS)
    acoustic sensor data
    under-water acoustic
    Opis:
    Maritime and port areas throughout the world are exposed to many different hazards, like pollution, terrorism and natural disasters. Early detection, identification and preparation of appropriate response strategies is especially important in the case of semi-enclosed basins like the Baltic Sea, mainly due to the marine ecosystems' continuous absorption of pollutants including oil, heavy metals and chemicals. Many of those agents are characterised by great toxicity and cause devastation of the natural environment. The huge development in the information technology provides the means and possibilities for much faster and more efficient access to survey data, allowing their remote, nearly real-time management, processing and visualisation. Several approaches and techniques of measurements are available in marine environment monitoring. These consist of direct sampling, airborne and satellite imagery, hydrological measurements using CTD probes, remote sensing with the use of electromagnetic waves, acoustic methods based on the data acquired by multibeam systems, side-scan sonars and singlebeam echosounders.
    Źródło:
    Hydroacoustics; 2009, 12; 17-24
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-7 z 7

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