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    Tytuł:
    Ultrasonic Synthetic Apertures: Review
    Autorzy:
    Nowicki, A.
    Gambin, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/176456.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    synthetic aperture
    effective aperture
    ultrasonography
    Opis:
    In the paper the concept of synthetic aperture used for high resolution/high frame rate ultrasonic imaging is reviewed. The synthetic aperture technique allows building extended “virtual” apertures, synthesized from smaller real aperture resulting in improved lateral resolution along full penetration depth without sacrificing the frame rate. Especially, four methods, synthetic aperture focusing (SAF), multi-element synthetic aperture focusing (M-SAF), synthetic receive aperture (SRA) and synthetic transmit aperture (STA) are addressed. The effective aperture function, describing two-way, far field radiation is a useful tool in beam pattern analysis. Some basic notations, which are used to calculate the effective aperture are introduced in Appendix.
    Źródło:
    Archives of Acoustics; 2014, 39, 4; 427-438
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of the Multi-element Synthetic Transmit Aperture Method for Medical Ultrasound Imaging Applications
    Autorzy:
    Tasinkevych, Y.
    Trots, I.
    Nowicki, A.
    Lewandowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/177208.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasound imaging
    synthetic aperture
    beamforming
    Opis:
    The paper presents the optimization problem for the multi-element synthetic transmit aperture method (MSTA) in ultrasound imaging applications. The optimal choice of the transmit aperture size is made as a trade-off between the lateral resolution, penetration depth and the frame rate. Results of the analysis obtained by a developed optimization algorithm are presented. The maximum penetration depth and lateral resolution at given depths are chosen as optimization criteria. The results of numerical experiments carried out in MATLAB Ž using synthetic aperture data of point reflectors obtained by the FIELD II simulation program are presented. The visualization of experimental synthetic aperture data of a tissue mimicking phantom and in vitro measurements of the beef liver performed using the SonixTOUCH Research system are also shown.
    Źródło:
    Archives of Acoustics; 2012, 37, 1; 47-55
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Short Range Synthetic Aperture Imaging Radar with Rotating Antenna
    Autorzy:
    Ali, F.
    Urban, A.
    Vossiek, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/226520.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    radar
    synthetic aperture
    scanning
    imaging
    Opis:
    The design of a short range synthetic aperture imaging radar is introduced in this paper. A radar hologram is acquired using a small omnidirectional antenna that is mounted on a rotating platform. After each turn of the platform a high resolution 360° 2D image is reconstructed; a rotating window function optimizes the reconstructed image function to get the best image focus for detecting both weak and strong scatterers. The rotating window function depends on the target direction and is executed for each image point and each target direction. The size of the synthetic aperture – and thus the lateral resolution of the imaging system – is determined by the diameter of the circular antenna trajectory. In contrast to common radar scanner concepts that utilize highly directional and thus bulky antennas, the proposed scanner concept has the advantage of using a small, lightweight omni-directional antenna. The developed radar system is much more compact and the scanning mechanics are significantly simplified. Furthermore, an omni-directional antenna offers very straightforward options for powering the radar on the rotation platform. Measurement results obtained with a 24 GHz FMCW short range radar sensor illustrate the performance of the proposed SAR imaging method.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 1; 97-102
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multi-Element Synthetic Transmit Aperture in Medical Ultrasound Imaging
    Autorzy:
    Trots, I.
    Nowicki, A.
    Lewandowski, M.
    Tasinkevych, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/177855.pdf
    Data publikacji:
    2010
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasound imaging
    synthetic aperture
    beamforming
    Opis:
    Synthetic aperture (SA) technique is a novel approach to present day commercial systems and has previously not been used in medical ultrasound imaging. The basic idea of SA is to combine information acquired simultaneously from all directions over a number of emissions and to reconstruct the full image from these data. The paper presents the multi-element STA (MSTA) method for medical ultrasound imaging. The main difference with the STA approach is the use of a few elements in the transmit mode in contrast to a single element aperture. This allows increasing the system frame rate, decreasing the number of emissions, and provides the best compromise between the penetration depth and lateral resolution. Besides, a modified MSTA is proposed with a corresponding RF signal correction in the receive mode, which accounts for the element directivity property. In the experiments a 32-element linear transducer array with 0.48 mm interelement spacing and a burst pulse of 100 ns duration were used. Two elements wide transmission aperture was used to generate an ultrasound wave covering the full image region. The comparison of 2D ultrasound images of a tissue mimicking phantom obtained using the STA and MSTA methods is presented to demonstrate the benefits of the second one.
    Źródło:
    Archives of Acoustics; 2010, 35, 4; 687-699
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthetic Aperture Radar Using Emitters of Opportunity
    Autorzy:
    Serafin, P.
    Kawalec, A.
    Leśnik, C.
    Pyć, M.
    Pietrasiński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/226408.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Synthetic Aperture Radar (SAR)
    passive SAR
    Opis:
    The capability of a radar imaging system to stay undetected while gathering data is one of the most desired for military reconnaissance systems. This is particularly difficult to achieve for synthetic aperture radar (SAR), that have to emit electromagnetic energy all the time during the operation and to move along a strictly defined route. Therefore the idea of a passive imaging system although encountering many constraints seems to be very interesting. The possibilities of a passive synthetic aperture radar system working with different types of emitters of opportunity are described in the paper. Impact of signal characteristics on image quality and geometry issues are discussed among others. Results of computer simulations of such a system implementing different imaging algorithms as well as the results of the experiment performed with passive SAR system model are presented.
    Źródło:
    International Journal of Electronics and Telecommunications; 2012, 58, 4; 357-362
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Object georeferencing in UAV-based SAR terrain images
    Autorzy:
    Łabowski, M.
    Kaniewski, P.
    Serafin, P.
    Wajszczyk, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/320583.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Forum Nawigacyjne
    Tematy:
    georeferencing
    synthetic aperture radar
    IMU
    GNSS
    Opis:
    Synthetic aperture radars (SAR) allow to obtain high resolution terrain images comparable with the resolution of optical methods. Radar imaging is independent on the weather conditions and the daylight. The process of analysis of the SAR images consists primarily of identifying of interesting objects. The ability to determine their geographical coordi-nates can increase usability of the solution from a user point of view. The paper presents a georeferencing method of the radar terrain images. The presented images were obtained from the SAR system installed on board an Unmanned Aerial Vehicle (UAV). The sys-tem was developed within a project under acronym WATSAR realized by the Military University of Technology and WB Electronics S.A. The source of the navigation data was an INS/GNSS system integrated by the Kalman filter with a feed-backward correc-tion loop. The paper presents the terrain images obtained during flight tests and results of selected objects georeferencing with an assessment of the accuracy of the method.
    Lotnicze zobrazowania terenu realizowane za pomocą radaru z syntetyczną aperturą pozwalają na uzyskanie wysokiej rozróżnialności porównywalnej z rozróżnialnością metod optycznych, mając jednocześnie nad nimi przewagę w postaci niezależności obserwacji od warunków pogodowych czy pory dnia. Proces analizy tak uzyskanych zobrazowań składa się przede wszystkim z identyfikacji interesujących obiektów. Możliwość określenia ich współrzędnych geograficznych pozwala na znaczące zwiększenie użyteczności tego rozwiązania z punktu widzenia potencjalnego użytkownika. W artykule przedstawiono metodę georeferencji zobrazowań terenu otrzymywanych za pomocą radaru z syntetyczną aperturą, który zainstalowano na pokładzie bezzałogowego statku powietrznego. System taki opracowano w ramach projektu WATSAR, zrealizowanego przez Wojskową Akademię Techniczną i WB Electronics S.A. Źródłem danych nawigacyjnych był system INS/GNSS, zintegrowany metodą filtracji pośredniej, z korekcją wstecz. W artykule zamieszczono radarowe zobrazowania terenu uzyskane podczas badań poligonowych systemu oraz wyniki georeferencji wybranych obiektów wraz z oceną dokładności wyznaczanego położenia.
    Źródło:
    Annual of Navigation; 2016, 23; 39-52
    1640-8632
    Pojawia się w:
    Annual of Navigation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application for Displaying Synthetic Aperture Radar Imagery in Real-time Implementation and Results
    Autorzy:
    Borowiec, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/226659.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Synthetic Aperture Radar (SAR)
    real-time imaging
    Opis:
    The paper presents implementation and results of the application for displaying SAR (Synthetic Aperture Radar) imagery operating in real-time. The application performs SAR imagery formation and displays results in real-time after receiving of preprocessed data via an SAR processing application. The application was used in SARape (Synthetic Aperture Radar for all weather penetrating UAV application) project founded by the European Defence Agency. The real-time operation is achieved thanks to implementation based on multithreading.
    Źródło:
    International Journal of Electronics and Telecommunications; 2015, 61, 4; 345-350
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthetic Aperture Technique Applied to Tissue Attenuation Imaging
    Autorzy:
    Klimonda, Z.
    Litniewski, J.
    Nowicki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/176945.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    tissue attenuation imaging
    synthetic aperture
    diagnosis enhancing
    Opis:
    The attenuating properties of biological tissue are of great importance in ultrasonic medical imaging. Investigations performed in vitro and in vivo showed the cor- relation between pathological changes in the tissue and variation of the attenuation coefficient. In order to estimate the attenuation we have used the downshift of mean frequency (fm) of the interrogating ultrasonic pulse propagating in the medium. To determine the fm along the propagation path we have applied the fm estimator (I/Q algorithm adopted from the Doppler mean frequency estimation technique). The mean-frequency shift trend was calculated using Single Spectrum Analysis. Next, the trends were converted into attenuation coefficient distributions and finally the parametric images were computed. The RF data were collected in simulations and experiments applying the synthetic aperture (SA) transmit-receiving scheme. In measurements the ultrasonic scanner enabling a full control of the transmission and reception was used. The resolution and accuracy of the method was verified using tissue mimicking phantom with uniform echogenicity but varying attenuation coefficient.
    Źródło:
    Archives of Acoustics; 2011, 36, 4; 927-935
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cascade Feed Forward Neural Network-based Model for Air Pollutants Evaluation of Single Monitoring Stations in Urban Areas
    Autorzy:
    Capizzi, G.
    Lo Sciuto, G.
    Monforte, P.
    Napoli, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/226736.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    neural networks
    Synthetic Aperture Radar (SAR)
    mahalanobis distance
    Opis:
    In this paper, air pollutants concentrations for NO2, NO, NOx and PM10 in a single monitoring station are predicted using the data coming from other different monitoring stations located nearby. A cascade feed forward neural network based modeling is proposed. The main aim is to provide a methodology leading to the introduction of virtual monitoring station points consistent with the actual stations located in the city of Catania in Italy.
    Źródło:
    International Journal of Electronics and Telecommunications; 2015, 61, 4; 327-332
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Generalized radar/radiometry imaging problems
    Autorzy:
    Prudyus, I.
    Voloshynovskiy, S.
    Synyavskyy, A.
    Holotyak, T.
    Lazko, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/309072.pdf
    Data publikacji:
    2001
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    radiometry systems
    Synthetic Aperture Radar (SAR)
    spatio-temporal imaging
    Opis:
    In the paper the results of spatio-temporal imaging simulation based on radar, synthetic aperture radar (SAR) and radiometry systems are presented. The analytical relationship between object scattering/emitting and the formed image is given and the general approach for the description of imaging system by means of Frendholm equation solution is developed. The potential limit of image resolution based on Rao-Cramer inequality is estimated.
    Źródło:
    Journal of Telecommunications and Information Technology; 2001, 4; 15-20
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mutually Orthogonal Golay Complementary Sequences in Synthetic Aperture Imaging Systems
    Autorzy:
    Trots, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/178145.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    coded excitation
    mutually orthogonal Golay codes
    synthetic aperture
    ultrasound imaging
    Opis:
    The main objective of this study is to improve the ultrasound image by employing a new algorithm based on transducer array element beam pattern correction implemented in the synthetic transmit aperture (STA) method combined with emission of mutually orthogonal complementary Golay sequences. Orthogonal Golay sequences can be transmitted and received by different transducer elements simultaneously, thereby decreasing the time of image reconstruction, which plays an important role in medical diagnostic imaging. The paper presents the preliminary results of computer simulation of the synthetic aperture method combined with the orthogonal Golay sequences in a linear transducer array. The transmission of long waveforms characterized by a particular autocorrelation function allows to increase the total energy of the transmitted signal without increasing the peak pressure. It can also improve the signal-to-noise ratio and increase the visualization depth maintaining the ultrasound image resolution. In the work, the 128-element linear transducer array with a 0.3 mm pitch excited by 8-bits Golay coded sequences as well as one cycle at nominal frequencies of 4 MHz were used. The comparison of 2D ultrasound images of the phantoms is presented to demonstrate the benefits of a coded transmission. The image reconstruction was performed using the synthetic STA algorithm with transmit and receive signals correction based on a single element directivity function.
    Źródło:
    Archives of Acoustics; 2015, 40, 2; 283-289
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spatially Diverse ISAR Imaging for Classification Performance Enhancement
    Autorzy:
    Brisken, S.
    Matthes, D.
    Mathy, T.
    Worms, J. G.
    Powiązania:
    https://bibliotekanauki.pl/articles/226557.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    inverse synthetic aperture radar
    multistatic radar
    non-cooperative target identification
    Opis:
    One popular approach to the problem of Non-Cooperative Target Identification is the use of 2D Inverse SAR images. Methods to successfully identify a target include the comparison of a set of scattering centers in the ISAR image to a database or the estimation of target dimensions. While working well in theory, these techniques face major difficulties in practice. In the conventional case of a monostatic radar, visibility of scattering centers varies with the target aspect angle due to fading. In this paper we examine that the visibility of scattering centers can be improved by incoherent addition of images from spatially distributed radars. The main focus lies in the description and results of a multistatic ISAR experiment carried out at Fraunhofer FHR. We display theoretically derived bistatic synchronization errors in a practical system and formulate additional multistatic synchronization requirements, necessary to add up the images.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 1; 15-22
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonuniform Spatial Sampling in a Ground-Based Noise SAR
    Autorzy:
    Maślikowski, Ł.
    Misiurewicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/226510.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nonuniform sampling
    noise radar
    synthetic aperture
    radar (SAR)
    compressive sampling
    Opis:
    The paper presents an idea of nonuniform spatial sampling applied to a noise synthetic aperture radar. In certain cases it is desirable to limit the number of spatial (alongtrack) domain samples acquired in a SAR radar because of external constraints on sampling frequency or on the overall number of samples – e.g. in order to economy on time or power consumed. Lowering number of samples taken may, however, lead to spatial aliasing and incorrect reconstruction of the image. Nonuniform sampling allows to reduce the aliasing effect and reconstruct the image better. This technique can be applied with standard reconstruction methods, but it works best together with Compressive Sensing reconstruction algorithms. The idea will be verified with an experimental noise SAR built at ISE PW.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 1; 71-75
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Radar Signatures of Complex Buried Objects in Ground Penetrating Radar
    Autorzy:
    Panzner, B.
    Jöstingmeier, A.
    Omar, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/226559.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    image reconstruction
    inverse scattering
    Synthetic Aperture Radar (SAR)
    GPR
    migration
    Opis:
    The evaluation of radar signatures of buried objects for three experimental ground penetrating radar setups will be addressed in this paper. The contribution will present corresponding results and experiences. The performance of the imaging capabilities of the designed radar system will be assessed by reconstruction of complex shaped test objects, which have been placed within the ground. The influence of system parameters of the ground penetrating radar have been varied systematically in order to analyze their effects on the image quality. Among the modified parameters are the step size in transverse plane, height of the antenna over ground, frequency range, frequency points, antennas and varying instrument settings. A signal processing technique based on synthetic aperture radar has been applied on the measured raw data. The focus radius around a specific target has been analyzed concerning the compromise between image quality and processing time. The experiments demonstrate that the designed ground penetrating radar systems are capable for detection of buried objects with high resolution.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 1; 9-14
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of Short-Lag Spatial Coherence Imaging Method
    Autorzy:
    Domaradzki, Jakub
    Lewandowski, Marcin
    Żołek, Norbert
    Powiązania:
    https://bibliotekanauki.pl/articles/176815.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    short lag spatial coherence
    synthetic aperture
    algorithm optimization
    parallel processing
    Opis:
    The computing performance optimization of the Short-Lag Spatial Coherence (SLSC) method applied to ultrasound data processing is presented. The method is based on the theory that signals from adjacent receivers are correlated, drawing on a simplified conclusion of the van Cittert-Zernike theorem. It has been proven that it can be successfully used in ultrasound data reconstruction with despeckling. Former works have shown that the SLSC method in its original form has two main drawbacks: time-consuming processing and low contrast in the area near the transceivers. In this study, we introduce a method that allows to overcome both of these drawbacks. The presented approach removes the dependency on distance (the “lag” parameter value) between signals used to calculate correlations. The approach has been tested by comparing results obtained with the original SLSC algorithm on data acquired from tissue phantoms. The modified method proposed here leads to constant complexity, thus execution time is independent of the lag parameter value, instead of the linear complexity. The presented approach increases computation speed over 10 times in comparison to the base SLSC algorithm for a typical lag parameter value. The approach also improves the output image quality in shallow areas and does not decrease quality in deeper areas.
    Źródło:
    Archives of Acoustics; 2019, 44, 4; 669-679
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mutually Orthogonal Golay Complementary Sequences in Medical Ultrasound Diagnostics. Experimental Study
    Autorzy:
    Trots, Ihor
    Żołek, Norbert
    Tasinkevych, Yuriy
    Wójcik, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/31340110.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    coded excitation
    mutually orthogonal Golay codes
    synthetic aperture
    ultrasound imaging
    Opis:
    The objective of this paper is an experimental study of the most crucial parameters of the received acoustic signals (e.g. signal-to-noise ratio (SNR), side-lobes level (SLL), axial resolution) obtained as a result of simultaneous emission of mutually orthogonal Golay complementary sequences (MOGCS) to demonstrate their feasibility of being used in ultrasound diagnostics. Application of the MOGCS in ultrasound measurements allows the image reconstruction time to be shortened without decreasing the resulting quality of reconstructed images in comparison with regular complementary Golay coded sequences (CGCS). In this paper two sets of 16-bits long MOGCS were implemented in the Verasonics Vantage™ (Verasonics Inc., Kirkland, WA, USA) scanner. Ultrasound data were generated using a perfect reflector, a custom-made nylon wire phantom and tissue mimicking phantom. Parameters of the detected MOGCS echoes like SNR, SLL and axial resolution were determined and compared to that of the standard CGCS and the short two-sine cycles pulse. It was evidenced that applying MOGCS did not compromise the parameters of the separated and compressed echoes in comparison to the other types of transmitted signal – the CGCS and the short pulse. Concretely, both the MOGCS and CGCS yield similar SNR increase in comparison to the short pulse. Almost similar values of the axial resolution estimated at the full width at the half maximum level for all types of the transmitted signals were also obtained. At the same time, using the MOGCS the data acquisition speed can be increased twice in comparison with the CGCS signal.
    Źródło:
    Archives of Acoustics; 2022, 47, 3; 399-405
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mapping of Surface Deformation and Displacement Associated with the 6.5 Magnitude Botswana Earthquake of 3 April 2017 Using DInSAR Analysis
    Autorzy:
    Thomas, Abraham
    Powiązania:
    https://bibliotekanauki.pl/articles/1837989.pdf
    Data publikacji:
    2020
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    differential interferometric synthetic aperture radar (DInSAR)
    interferometry
    Sentinel-1
    Botswana earthquake
    Opis:
    The DInSAR analysis was performed for mapping surface deformation and displacement associated with the 6.5 magnitude Botswana earthquake of 3 April 2017 using Sentinel 1 data and SNAP. The analyses involved: coregistration of SAR images, interferogram formation, debursting, merging of sub swaths, topographic phase removal, phase filtering, phase unwrapping, orthorectification and calculation of vertical displacement for two situations (unmasked and masked with a layer of coherence ≥0.6). The vertical displacement for the unmasked situation ranged from −122 mm to +136 mm whereas in the masked layer it ranged from −84 mm to +122 mm. Negative surface deformation (subsidence) is seen in the epicentre region and eastern, north eastern, northern areas of the image whereas major positive surface deformations (uplift) are seen in the south western, western and north western corner part. Comparison of displacements with geology revealed that major deformation occurred in the Karoo basalts and lesser surface deformation has occurred in the Lebung Group rocks of the northern, NE and SW region. The elongated shape of deformation near the epicentre and positive vertical displacement seen towards the SW of the epicentre and negative vertical displacement seen towards NE of the epicentre reveals that the region has undergone uplifting and subsidence on either side of the area close to the epicentre (similar to faulting in a NW or SE direction). The boundaries of the uplift and subsidence regions inferred as long lineaments were digitised as faults. Comparison of the deformation with existing seismotectonic map revealed the existence of some north westerly faults seen in the region.
    Źródło:
    Geomatics and Environmental Engineering; 2020, 14, 4; 81-100
    1898-1135
    Pojawia się w:
    Geomatics and Environmental Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Golay Coded Sequences in Synthetic Aperture Imaging Systems
    Autorzy:
    Trots, I.
    Tasinkevych, Y.
    Nowicki, A.
    Lewandowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/176941.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasound imaging
    synthetic aperture
    beamforming
    radiation pattern
    coded sequences
    Golay codes
    Opis:
    The paper presents the theoretical and experimental study of synthetic transmit aperture (STA) method combined with Golay coded transmission for medical ultrasound imaging applications. The transmission of long waveforms characterized by a particular autocorrelation function allows to increase the total energy of the transmitted signal without increasing the peak pressure. It can also improve signal- to-noise ratio and increase the visualization depth maintaining the ultrasound image resolution. In the work the 128-element linear transducer array with 0.3 mm pitch excited by the 8 and 16-bits Golay coded sequences as well as a one cycle at nominal frequencies 4 MHz were used. The comparison of 2D ultrasound images of the tissue mimicking phantoms is presented to demonstrate the benefits of coded transmission. The image reconstruction was performed using synthetic STA algorithm with transmit and receive signals correction based on a single element directivity function.
    Źródło:
    Archives of Acoustics; 2011, 36, 4; 913-926
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spatial and Frequency Compounding in Application to Attenuation Estimation in Tissue
    Autorzy:
    Klimonda, Z.
    Litniewski, J.
    Karwat, P.
    Nowicki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/177604.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    tissue attenuation estimation
    parametric imaging
    synthetic aperture
    spatial compounding
    frequency compounding
    Opis:
    The soft tissue attenuation is an interesting parameter from medical point of view, because the value of attenuation coefficient is often related to the state of the tissue. Thus, the imaging of the attenuation coefficient distribution within the tissue could be a useful tool for ultrasonic medical diagnosis. The method of attenuation estimation based on tracking of the mean frequency changes in a backscattered signal is presented in this paper. The attenuation estimates are characterized by high variance due to stochastic character of the backscattered ultrasonic signal and some special methods must be added to data processing to improve the resulting images. The following paper presents the application of Spatial Compounding (SC), Frequency Compounding (FC) and the combination of both. The resulting parametric images are compared by means of root-mean-square errors. The results show that combined SC and FC techniques significantly improve the quality and accuracy of parametric images of attenuation distribution.
    Źródło:
    Archives of Acoustics; 2014, 39, 4; 519-527
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    3D Synthetic Aperture Imaging Method in Spectrum Domain for Low-Cost Portable Ultrasound Systems
    Autorzy:
    Tasinkiewicz, Jurij
    Powiązania:
    https://bibliotekanauki.pl/articles/31339771.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    ultrasound imaging
    matrix transducer
    delay-and-sum
    Fourier transform
    synthetic aperture
    Opis:
    Portable, hand-held ultrasound devices capable of 3D imaging in real time are the next generation of the medical imaging apparatus adapted not only for professional medical stuff but for a wide group of less advanced users. Limited power supply capacity and the relatively small number of channels used for the ultrasound data acquisition are the most important limitations that should be taken into account when designing such devices and when developing the corresponding image reconstruction algorithms. The aim of this study was to develop a new 3D ultrasound imaging method which would take into account the above-mentioned features of the new generation of ultrasonic devices – low-cost portable general access scanners. It was based on the synthetic transmit aperture (STA) method combined with the Fourier spectrum domain (SD) acoustic data processing. The STA using a limited number of elements in transmit and receive modes for ultrasound data acquisition allowed both aforementioned constraints to be obeyed simultaneously. Moreover, the computational speed of the fast Fourier transform (FFT) algorithm utilized for the ultrasound image synthesis in the spectrum domain makes the proposed method to be more competitive compared to the conventional time domain (TD) STA method based on the delay-and-sum (DAS) technique, especially in the case of 3D imaging in real time mode. Performance of the proposed method was verified using numerical 3D acoustic data simulated in the Field II program for MATLAB and using experimental data from the custom design 3D scattering phantom collected by means of the Verasonics Vantage 256™ research ultrasound system equipped with the dedicated 1024-element 2D matrix transducer. The method proposed in this paper was about 80 times faster than its counterpart based on the time domain synthetic transmit aperture (TD-STA) approach in the numerical example of a single 3D ultrasound image synthesized from 4 partial images each containing 64 × 64 × 512 pixels. It was also shown that the acceleration of the image reconstruction was achieved at the cost of a slight deterioration in the image quality assessed by the contrast and contrast-to-noise ratio (CNR).
    Źródło:
    Archives of Acoustics; 2023, 48, 4; 559-572
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Radar and Optical Images Fusion Using Stripmap SAR Data with Multilook Processing
    Autorzy:
    Kulpa, K.
    Malanowski, M.
    Misiurewicz, J.
    Samczynski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/226571.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Synthetic Aperture Radar (SAR)
    focused SAR
    multilook
    multilook colour mapping
    data fusion
    Opis:
    The paper presents the real-life data results of SAR and optical images data fusion. The fusion has been carried out for SAR images obtained in stripmap SAR mode using multilook processing with different methods of final image creation. The aim of the fusion was to enhance the target recognition capabilities on the Earth surface for a simple single-channel SAR receiver.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 1; 37-42
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimizing the minimum cost flow algorithm for the phase unwrapping process in SAR radar
    Autorzy:
    Dudczyk, J.
    Kawalec, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/200190.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    IFSAR
    Interferometry Synthetic Aperture Radar
    minimum cost flow
    MCF
    phase unwrapping
    PhU
    Opis:
    The last three decades have been abundant in various solutions to the problem of Phase Unwrapping in a SAR radar. Basically, all the existing techniques of Phase Unwrapping are based on the assumption that it is possible to determine discrete ”derivatives” of the unwrapped phase. In this case a discrete derivative of the unwrapped phase means a phase difference (phase gradient) between the adjacent pixels if the absolute value of this difference is less than π. The unwrapped phase can be reconstructed from these discrete derivatives by adding a constant multiple of 2π. These methods differ in that the above hypothesis may be false in some image points. Therefore, discrete derivatives determining the unwrapped phase will be discontinuous, which means they will not form an irrotational vector field. Methods utilising branch-cuts unwrap the phase by summing up specific discrete partial derivatives of the unwrapped phase along a path. Such an approach enables internally cohesive results to be obtained. Possible summing paths are limited by branch-cuts, which must not be intersected. These branch-cuts connect local discontinuities of discrete partial derivatives. The authors of this paper performed parametrization of the Minimum Cost Flow algorithm by changing the parameter determining the size of a tile, into which the input image is divided, and changing the extent of overlapping of two adjacent tiles. It was the basis for determining the optimum (in terms of minimum Phase Unwrapping time) performance of the Minimum Cost Flow algorithm in the aspect of those parameters.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 3; 511-516
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Data Reduction Method for Synthetic Transmit Aperture Algorithm
    Autorzy:
    Karwat, P.
    Klimonda, Z.
    Sęklewski, M.
    Lewandowski, M.
    Nowicki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/177848.pdf
    Data publikacji:
    2010
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasonic imaging
    synthetic transmit aperture
    data reduction
    effective aperture
    reciprocity
    Opis:
    Ultrasonic methods of human body internal structures imaging are being continuously enhanced. New algorithms are created to improve certain output parameters. A synthetic aperture method (SA) is an example which allows to display images at higher frame-rate than in case of conventional beam-forming method. Higher computational complexity is a limitation of SA method and it can prevent from obtaining a desired reconstruction time. This problem can be solved by neglecting a part of data. Obviously it implies a decrease of imaging quality, however a proper data reduction technique would minimize the image degradation. A proposed way of data reduction can be used with synthetic transmit aperture method (STA) and it bases on an assumption that a signal obtained from any pair of transducers is the same, no matter which transducer transmits and which receives. According to this postulate, nearly a half of the data can be ignored without image quality decrease. The presented results of simulations and measurements with use of wire and tissue phantom prove that the proposed data reduction technique reduces the amount of data to be processed by half, while maintaining resolution and allowing only a small decrease of SNR and contrast of resulting images.
    Źródło:
    Archives of Acoustics; 2010, 35, 4; 635-642
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of range stacking and omega-k algorithms in synthetic aperture sonar processing
    Porównanie algorytmów omega-k oraz range stacking w przetwarzaniu SAS
    Autorzy:
    Szczegielniak, M.
    Szczegielniak, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/389862.pdf
    Data publikacji:
    2012
    Wydawca:
    Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydawnictwo PB
    Tematy:
    synthetic aperture sonar
    range stacking
    omega-k
    comparison
    sonar z syntetyczną aperturą
    porównanie
    Opis:
    Synthetic Aperture Sonar (SAS) processing is continuously developing into a direction of better, more effective and accurate algorithms. It is preferable to use algorithms which don’t introduce additional errors because of a phase approximation or digital data interpolation. One of them is Range Stacking. The short analysis of this algorithm, emphasizing its advantages and disadvantages in comparison with another reconstruction algorithm called Omega-k, was carried out in the paper. The simulated raw SAS signals for the stripmap mode were the basis of the practical part of the comparison. The set of examined SAS images included some signals after the spatial filtering with the use of Polar Format Processing. The results of the numerical simulation are shown and discussed in this paper.
    Przetwarzanie SAS (Synthetic Aperture Sonar) jest wciąż rozwijane w kierunku lepszych, bardziej efektywnych oraz dokładnych algorytmów. Pożądane jest stosowanie algorytmów, które nie wprowadzają dodatkowych błędów z powodu aproksymacji fazy lub cyfrowej interpolacji danych. Jednym z takich algorytmów jest "Range Stacking". W artykule zaprezentowano jego krótką charakterystykę z wyróżnieniem jego wad i zalet w stosunku do innego, chętnie stosowanego algorytmu rekonstrukcji Omega-k. Wygenerowane sygnały SAS dla trybu "stripmap" zostały wykorzystane do praktycznego porównania obydwu algorytmów. Zbiór symulowanych obrazów SAS zawierał również sygnały przefiltrowane przestrzennie za pomocą algorytmu "Polar Format Processing". Wyniki numerycznych symulacji zostały zaprezentowane i przedyskutowane w artykule.
    Źródło:
    Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy; 2012, 16; 27-39
    1899-0088
    Pojawia się w:
    Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of Flight Path Deviations for SAR Radar Installed on UAV
    Autorzy:
    Łabowski, M.
    Kaniewski, P.
    Konatowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/221533.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Unmanned Aerial Vehicle
    Synthetic Aperture Radar
    inertial measurement unit
    Global Navigation Satellite System
    Opis:
    The paper presents a method of calculation of position deviations from a theoretical, nominally rectilinear trajectory for a SAR imaging system installed on board of UAV. The UAV on-board system consists of a radar sensor, an antenna system, a SAR processor and a navigation system. The main task of the navigation part is to determine the vector of differences between the theoretical and the measured trajectories of UAV center of gravity. The paper includes chosen results of experiments obtained during ground and flight tests.
    Źródło:
    Metrology and Measurement Systems; 2016, 23, 3; 383-391
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An improved Otsu method for oil spill detection from SAR images
    Autorzy:
    Yu, F.
    Sun, W.
    Li, J.
    Zhao, Y.
    Zhang, Y.
    Chen, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/47553.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    remote sensing
    oil spill
    detection
    Otsu's method
    accident
    marine transport
    synthetic aperture radar
    Opis:
    In recent years, oil spill accidents have become increasingly frequent due to the development of marine transportation and massive oil exploitation. At present, satellite remote sensing is the principal method used to monitor oil spills. Extracting the locations and extent of oil spill spots accurately in remote sensing images reaps significant benefits in terms of risk assessment and clean-up work. Nowadays the method of edge detection combined with threshold segmenta- tion (EDCTS) to extract oil information is becoming increasingly popular. However, the current method has some limitations in terms of accurately extracting oil spills in synthetic aperture radar (SAR) images, where heterogeneous background noise exists. In this study, we propose an adaptive mechanism based on Otsu method, which applies region growing combined with both edge detection and threshold segmentation (RGEDOM) to extract oil spills. Remote sensing images from the Bohai Sea on June 11, 2011 and the Gulf of Dalian on July 17, 2010 are utilized to validate the accuracy of our algorithm and the reliability of extraction results. In addition, results according to EDCTS are used as a comparator to further explore validity. The comparison with results according to EDCTS using the same dataset demonstrates that the proposed self-adapting algorithm is more robust and boasts high-accuracy. The accuracy computing by the adaptive algorithm is significantly improved compared with EDCTS and threshold method.
    Źródło:
    Oceanologia; 2017, 59, 3
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Azimuth ambiguity suppression in SAR images using Doppler-sensitive signals
    Autorzy:
    Leśnik, Cz.
    Serafin, P.
    Kawalec, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/200612.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Synthetic Aperture Radar (SAR)
    SAR
    azimuth ambiguity
    Doppler-sensitive signals
    dwuznaczność azymutu
    sygnał Dopplera
    Opis:
    In the article the problem of the azimuth ambiguity in synthetic aperture radar (SAR) images and its genesis are presented. A method of suppressing the ambiguities by utilization of Doppler-sensitive signals is proposed, and the necessary modifications to the SAR synthesis algorithm are discussed. The SAR system parameters required for an optimal performance of the method are discussed and simulation results are presented.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 1; 221-227
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An analysis of Chosen Image Formation Algorithms for Synthetic Aperture Radar with FMCW
    Autorzy:
    Okoń-Fąfara, M.
    Serafin, P.
    Kawalec, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/227061.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    signal processing
    synthetic aperture radar
    time domain correlation
    range-Doppler algorithm
    range migration algorithm
    Opis:
    The modelling of FMCW SAR systems, due to long signal duration time, commonly used start-stop approximation for pulsed radars causes errors in the image. Continuous motion of the radar platform results in additional range-azimuth couplings and range walk term that should be considered in processing of signal from this type of radar. The paper presents an analysis of the following algorithms: Time Domain Correlation (TDC), Range Doppler Algorithm (RDA), and Range Migration Algorithm (RMA). The comparison of the algorithms is based on theoretical estimation of their computation complexity and the quality of images obtained on the basis of real signals of FMCW SAR systems.
    Źródło:
    International Journal of Electronics and Telecommunications; 2016, 62, 4; 323-328
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Circular Radon Transform Inversion Technique in Synthetic Aperture Ultrasound Imaging : an Ultrasound Phantom Evaluation
    Autorzy:
    Tasinkevych, J.
    Trots, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/176632.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    synthetic aperture focusing method
    circular Radon Transform
    delay and sum beamforming
    range migration algorithm
    Opis:
    The paper presents an overview of theoretical aspects of ultrasound image reconstruction techniques based on the circular Radon transform inversion. Their potential application in ultrasonography in a similar way as it was successfully done in the x-ray computer tomography is demonstrated. The meth- ods employing Radon transform were previously extensively explored in the synthetic aperture radars, geophysics, and medical imaging using x-ray computer tomography. In this paper the main attention is paid to the ultrasound imaging employing monostatic transmit-receive configuration. Specifically, a single transmit and receive omnidirectional source placed at the same spatial location is used for generation of a wide-band ultrasound pulse and detection of back-scattered waves. The paper presents derivation of the closed-form solution of the CRT inversion algorithms by two different approaches: the range-migration algorithm (RMA) and the deconvolution algorithm (DA). Experimentally determined data of ultrasound phantom obtained using a 32-element 5 MHz linear transducer array with 0.48 mm element pitch and 0.36 mm element width and 5 mm height, excited by a 2 sine cycles burst pulse are used for comparison of images reconstructed by the RMA, DA, and conventional synthetic aperture focusing technique (SAFT). It is demonstrated that both the RMA and SAFT allow better lateral resolution and visualization depth to be achieved as compared to the DA approach. Comparison of the results obtained by the RMA method and the SAFT indicates slight improvement of the lateral resolution for the SAFT of approximately 1.5 and 1.6% at the depth of 12 and 32 mm, respectively. Concurrently, however, the visualization depth increase for the RMA is shown in comparison with the SAFT. Specifically, the scattered echo amplitude increase by the factor of 1.36 and 1.12 at the depth of 22 and 32 mm is demonstrated. It is also shown that the RMA runs about 30% faster than the SAFT and about 12% faster than the DA method.
    Źródło:
    Archives of Acoustics; 2014, 39, 4; 569-582
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthetic Aperture Cardiac Imaging with Reduced Number of Acquisition Channels. A Feasibility Study
    Autorzy:
    Tasinkevych, Y.
    Lewandowski, M.
    Klimonda, Z.
    Walczak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/177629.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    phased-array
    ultrasound imaging
    diverging wave
    synthetic transmit aperture
    Opis:
    Commercially available cardiac scanners use 64-128 elements phased-array (PA) probes and classical delay-and-sum beamforming to reconstruct a sector B-mode image. For portable and hand-held scanners, which are the fastest growing market, channel count reduction can greatly decrease the total power and cost of devices. The introduction of ultra-fast imaging methods based on plane waves and diverging waves provides new insight into heart’s moving structures and enables the implementation of new myocardial assessment and advanced flow estimation methods, thanks to much higher frame rates. The goal of this study was to show the feasibility of reducing the channel count in the diverging wave synthetic aperture image reconstruction method for phased-arrays. The application of ultra-fast 32-channel subaperture imaging combined with spatial compounding allowed the frame rate of approximately 400 fps for 120 mm visualization to be achieved with image quality obtained on par with the classical 64-channel beamformer. Specifically, it was shown that the proposed method resulted in image quality metrics (lateral resolution, contrast and contrast-to-noise ratio), for a visualization depth not exceeding 50 mm, that were comparable with the classical PA beamforming. For larger visualization depths (80-100 mm) a slight degradation of the above parameters was observed. In conclusion, diverging wave phased-array imaging with reduced number of channels is a promising technology for low-cost, energy efficient hand-held cardiac scanners.
    Źródło:
    Archives of Acoustics; 2018, 43, 3; 437-446
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Upwelling dynamics in the Baltic Sea studied by a combined SAR-infrared satellite data and circulation model analysis
    Autorzy:
    Gurova, E.
    Lehmann, A.
    Ivanov, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/48338.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    Baltic Sea
    coastal upwelling
    MODIS satellite image
    circulation model
    synthetic aperture radar
    sea surface temperature
    wind stress
    Źródło:
    Oceanologia; 2013, 55, 3
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    S-band and Ku-band SAR system development for UAV-based applications
    Autorzy:
    Kaniewski, Piotr
    Komorniczak, Wojciech
    Leśnik, Czesław
    Cyrek, Jacek
    Susek, Waldemar
    Serafin, Piotr
    Łabowski, Michał
    Powiązania:
    https://bibliotekanauki.pl/articles/221666.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    unmanned aerial vehicle
    UAV
    synthetic aperture radar
    SAR
    Range–Doppler algorithm
    RDA
    imagery intelligence system
    IMINT system
    Opis:
    This paper describes a synthetic aperture radar system for tactical-level imagery intelligence installed on board an unmanned aerial vehicle. Selected results of its tests are provided. The system contains interchangeable S-band and Ku-band linear frequency-modulated, continuous wave radar sensors that were built within a frame of a research project named WATSAR, conducted by the Military University of Technology and WB Electronics S.A. One of several algorithms of radar image synthesis, implemented in the scope of the project, is described in this paper. The WATSAR system can create online and off-line radar images.
    Źródło:
    Metrology and Measurement Systems; 2019, 26, 1; 53-64
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Imprints of atmospheric waves on the Black Sea surface in data of ocean color scanners
    Autorzy:
    Evdoshenko, M.A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2079182.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    remote sensing
    ocean optics
    Black Sea
    sea surface
    synthetic aperture radar
    microwave radiation
    boundary layer
    satellite observation
    Opis:
    Data from MERIS onboard Envisat and MODIS onboard Terra and Aqua for 15–16 May 2010 were used to study powerful imprints of atmospheric gravity waves (AGWs) on the western part the Black Sea surface. Two cold fronts crossed the sea following the warm front and caused the AGWs which modulated the sea surface. Imprints of AGWs appeared as stripes of alternating brightness, they had crest length more than a hundred kilometers and wavelength of units of kilometers. Wave amplitude of AGWs imprints, evaluated by a 90%-depth of light penetration into the sea at 490 nm z90, the value inverse to the diffuse attenuation coefficient Kd_490, was units of decimeterxs. MODIS 250-m data of remote sensing reflectance, wind components and atmospheric pressure near the sea surface were obtained by processing the top of atmosphere data with the SeaDAS software package. Negative correlations of fluctuations of z90 with fluctuations of wind stress and atmospheric pressure were found on the transects of more than ten kilometers. The impact of wind stress on the origination of AGW imprints was found to be determinant, while the impact of atmospheric pressure was not more than units of percent.
    Źródło:
    Oceanologia; 2020, 62, 3; 255-266
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modifications of Range-Doppler Algorithm for Compensation of SAR Platform Motion Instabilities
    Autorzy:
    Gorovyi, I. M.
    Bezvesilniy, O. O.
    Vavriv, D. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/226865.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Synthetic Aperture Radar (SAR)
    SAR
    range-Doppler algorithm
    RDA
    multi-look processing
    image formation
    radiometric errors
    autofocus
    Opis:
    Two modifications of the range-Doppler algorithm (RDA) have been proposed to solve problems of SAR platform motion instabilities. First, the multi-look processing based on the RDA with an extended Doppler bandwidth has been introduced for correction of radiometric errors. Second, the RDA has been modified to perform SAR image formation on short-time acquisition intervals to use it in a recently-developed local-quadratic map-drift autofocus (LQMDA) method. The performance of the methods is illustrated with experimental data obtained by airborne SAR systems.
    Źródło:
    International Journal of Electronics and Telecommunications; 2014, 60, 3; 225-231
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Monitoring of displacements and deformations of the earth’s surface near the Stebnyk city using radar images of Sentinel-1
    Autorzy:
    Trevoho, Ihor
    Chetverikov, Borys
    Babiy, Lubov
    Malanchuk, Mariia
    Powiązania:
    https://bibliotekanauki.pl/articles/145388.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    interferometria radarowa
    radar
    deformacja powierzchni
    radar interferometry
    Synthetic Aperture Radar
    Sentinel-1
    deformations of the Earth’s surface
    Opis:
    This article applies radar interferometry technologies implemented in the ENVI SARscape and SNAP software environment provided by the processing of data from the Sentinel-1 satellite. The study was carried out based on six radar images of Sentinel-1A and Sentinel -1B taken from September 2017 until February 2018 with an interval of one month and on the radar-module of the already mentioned SNAP software. The main input data for solving the considered problem are radar images received from the satellite Sentinel-1B on the territory of Stebnyk-Truskavets for six months with an interval of one month. Monitoring of the Earth’s surface using radar data of the Sentinel-1A with a synthesized aperture is implemented with the application of interferometric methods of Persistent Scatterers and Small baselines interferometry for estimating small displacements of the Earth’s surface and structures. The obtained quantitative and qualitative indicators of monitoring do not answer the processes that take place and lead to vertical displacements the six months but do provide an opportunity to assess the extent and trends of their development. The specification in each case can be accomplished by ground methods, which greatly simplify the search for sites with critical parameters of vertical displacements which can have negative consequences and lead to an emergency.
    Źródło:
    Geodesy and Cartography; 2020, 69, 1; 85-96
    2080-6736
    2300-2581
    Pojawia się w:
    Geodesy and Cartography
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of synthetic aperture radar interferometry to monitor surface deformations of the Trans-European Transport Network (TEN-T) - a case study of the motorways crossing areas of mining operations in the Upper Silesian coal basin, Poland
    Autorzy:
    Stawinoga, Mariusz
    Pindel, Tomasz
    Smoliński, Adam
    Powiązania:
    https://bibliotekanauki.pl/articles/2073901.pdf
    Data publikacji:
    2021
    Wydawca:
    Główny Instytut Górnictwa
    Tematy:
    mining activities
    interferometric synthetic aperture radar
    inSAR
    road deformation
    highway
    działalność górnicza
    satelitarna interferometria radarowa
    deformacja dróg
    autostrada
    Opis:
    Underground hard coal mining causes surface deformations. When the mining operations are conducted beneath linear objects, such as motorways, there is a risk of deformations of the axis of the road and its horizontal and vertical alignment (additional bends and vertical curvatures, longitudinal inclinations, deformations of cross-sections). In the areas subjected to mining operations, mining plants conduct geodetic monitoring. Due to their labour intensity and costs, geodetic measurements are usually made only a few times a year. The article discusses the possibility of applying Interferometric Synthetic Aperture Radar (InSAR) to monitor the subsidence of the vertical alignment of motorways caused by mining operations and its advantages and disadvantages compared to the currently used methods of geodetic measurements. The tests were conducted in two sections of motorways within the Upper Silesian Coal Basin (Poland) in the areas of intensive hard coal mining operations. Radar imaging of the surface made by the European Space Agency's (ESA) satellite Sentinel-1 equipped with the Synthetic Aperture Radar (SAR) was used.
    Źródło:
    Journal of Sustainable Mining; 2021, 20, 3; 136--143
    2300-1364
    2300-3960
    Pojawia się w:
    Journal of Sustainable Mining
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of UAV Position with Use of Smoothing Algorithms
    Autorzy:
    Kaniewski, P.
    Gil, R.
    Konatowski, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/221380.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Unmanned Aerial Vehicle
    Inertial Navigation System
    Global Navigation Satellite System
    Integrated Navigation System
    Synthetic Aperture Radar
    Kalman Filter
    smoothing algorithm
    Opis:
    The paper presents methods of on-line and off-line estimation of UAV position on the basis of measurements from its integrated navigation system. The navigation system installed on board UAV contains an INS and a GNSS receiver. The UAV position, as well as its velocity and orientation are estimated with the use of smoothing algorithms. For off-line estimation, a fixed-interval smoothing algorithm has been applied. On-line estimation has been accomplished with the use of a fixed-lag smoothing algorithm. The paper includes chosen results of simulations demonstrating improvements of accuracy of UAV position estimation with the use of smoothing algorithms in comparison with the use of a Kalman filter.
    Źródło:
    Metrology and Measurement Systems; 2017, 24, 1; 127-142
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tools for optimizing performance of VOYages at sea
    Autorzy:
    Johannessen, J. A.
    Perrin, A.
    Gaultier, L.
    Herlédan, S.
    Pouplin, C.
    Collard, F.
    Maze, J. P.
    Dussauze, M.
    Rapp, J.
    Fanebust, R.
    Andersen, S.
    Franks, O.
    Meyer, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1841544.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    voyage at sea
    Copernicus Marine Environment Monitoring Service
    optimization tool
    synthetic aperture radar
    finite-size lyapunov exponent
    route optimization
    sea surface temperature
    route optimization algorithm
    Opis:
    The aim of the TOPVOYS project supported by the MarTERA ERA-Net Cofund program within the European Commission is to advance and implement analyses tools and decision support system for voyage optimisation. Based on marine weather analyses and forecasts combined with near real time satellite-based observations of wind, wave and surface current conditions as well as sea surface temperature fields the best shipping route are examined. The proposed approach aims to identify the optimum balance between minimisation of transit time and fuel consumption as well as reduction of emissions without placing the vessel at risk to damage and or crew injury. As such it is compliant with the International Maritime Organization guidelines [6] for ship routeing to keep the traffic smooth and avoid accidents, notably in the presence of unfavorable marine meteorological conditions. The tool performances will be demonstrated both in post-voyage analyses and real time operations for the North Atlantic Ocean crossings, voyages from Europe through the Mediterranean Sea and the Suez Channel to the Far East (e.g. China, South Korea) and voyages around Southern Africa.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2021, 15, 1; 233-239
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ship-iceberg detection & classification in sentinel-1 SAR images
    Autorzy:
    Heiselberg, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/117491.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    arctic shipping
    ship-iceberg detection
    sentinel-1
    Synthetic Aperture Radar (SAR)
    European Space Agency (ESA)
    SAR Imagery
    copernicus program
    ground range detected
    high resolution (GRDH)
    Opis:
    The European Space Agency Sentinel-1 satellites provide good resolution all weather SAR images. We describe algorithms for detection and classification of ships, icebergs and other objects at sea. Sidelobes from strongly reflecting objects as large ships are suppressed for better determination of ship parameters. The resulting improved ship lengths and breadths are larger than the ground truth values known from Automatic Identification System (AIS) data due to the limited resolution in the processing of the SAR images as compared to previous analyses of Sentinel-2 optical images. The limited resolution in SAR imagery degrades spatial classification algorithms but it is found that the backscatter horizontal and vertical polarizations can be exploited to distinguish icebergs in the Arctic from large ships but not small boats or wakes.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2020, 14, 1; 235-241
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numeryczne dane wysokościowe misji TanDEM-X
    Digital elevation models of TanDEM-X mission
    Autorzy:
    Woroszkiewicz, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/210271.pdf
    Data publikacji:
    2015
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    misja TanDEM-X
    misja SRTM
    interferometria radarowa
    numeryczny model pokrycia terenu
    TanDEM-X
    SRTM
    interferometry synthetic aperture radar
    digital elevation model (DEM)
    digital surface model
    Opis:
    Zapoczątkowana w 2010 roku misja TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) jest pierwszą satelitarną misją radarową, w ramach której zostały pozyskane dane interferometryczne w trybie bistatic InSARstripmap przez dwa bliźniacze satelity TerraSAR-X (TSX) oraz TanDEM-X (TDX) tworzące formację Helix. Realizacja tej konfiguracji ma na celu budowę numerycznego modelu pokrycia terenu (NMPT) o zasięgu globalnym w standardzie HRTI-3 (High Resolution Terrain Information). W artykule przedstawiono opis i specyfikację podstawowych produktów misji, jakimi są m.in. numeryczne modele pokrycia terenu, a także dodatkowych komponentów w postaci warstw informacyjnych i masek. Opisane zostało również zastosowanie techniki interferometrii radarowej w procesie budowy numerycznego modelu pokrycia terenu w postaci cyfrowej.
    Started in 2010 TanDEM-X mission (TerraSAR-X add-on for Digital Elevation Measurement) is the first space borne radar interferometer mission that acquires interferometric data in bistatic InSARstripmap mode with two spacecrafts TerraSAR-X (TSX) and TanDEM-X (TDX) flying in Helix formation. That configuration enables generation of a global digital elevation model compatible with the HRTI-3 standard. This paper presents an overview and specification of primary products of the TanDEM-X mission, i.e. digital elevation models and additional components such as information layers and masks. Moreover, the use of radar interferometry techniques for generation of the digital elevation model (DEM) and applications of InSARare discribed.
    Źródło:
    Biuletyn Wojskowej Akademii Technicznej; 2015, 64, 1; 33-46
    1234-5865
    Pojawia się w:
    Biuletyn Wojskowej Akademii Technicznej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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