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Tytuł:
Wideband beamformer in the frequency domain
Autorzy:
Elminowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/332683.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustics
wideband sonar
beamforming
Opis:
In modern high resolution wideband sonars using linear array, beamforming constitutes one of the most difficult problems. This paper presents a new efficient method of beamforming in the frequency domain. Applying fast Fourier transforms: to transfer into the frequency domain - temporal FFT (TFFT); to make spatial filtration spatial FFT (SFFT) and to transfer from the frequency domain - inverse FFT (IFFT), as well as fast convolution in the frequency domain correlating the conjugated and corrected replicas for each beam with picked up samples of SFFT for each frequency and each beam we obtain a processing that is less calculations burdened than other known processing algorithms.
Źródło:
Hydroacoustics; 2003, 6; 235-242
1642-1817
Pojawia się w:
Hydroacoustics
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:
A simulation of thinning of microphone array in near-field broadband beamformers
Autorzy:
Wielgus, Agnieszka
Szlachetko, Bogusław
Powiązania:
https://bibliotekanauki.pl/articles/2146656.pdf
Data publikacji:
2021
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
acoustics
beamforming systems
microphone array
thinning technique
akustyka
beamforming
macierz mikrofonów
technika przerzedzania
Opis:
This paper is devoted to the problem of designing an optimal microphone matrix. We define a criterion function where the performance of our matrix should be as close as possible to the desired one based on L2 norm. In the classical approach, increasing a size of the matrix is used to improve the system performance. However, in many cases it is not a good solution. In this paper we propose a solution based on thinning technique. We work with rectangular, equispaced microphone matrix and using metaheuristic approach called simulated annealing we optimise the set of active microphones (we switch off some of the microphones from the regular matrix). For illustrations, few numerical examples are solved. Comparing to the classical approach we show that thinning microphone matrix can significantly improve system performance.
Źródło:
Vibrations in Physical Systems; 2021, 32, 2; art. no. 2021204
0860-6897
Pojawia się w:
Vibrations in Physical Systems
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:
Sound recording with the application of microphone arrays
Autorzy:
Kornatowski, E.
Powiązania:
https://bibliotekanauki.pl/articles/97513.pdf
Data publikacji:
2011
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
sound recording
array microphone
beamforming
microphone
Opis:
In this article the issues concerning sound recording with the use of three-dimensional systems of several microphones were considered. The issues under study concern the so called beamforming, which is modeling three-dimensional directivity patterns of microphone arrays, as well as modern technologies of multichannel recording production with the purpose of reproduction in surround sound systems.
Źródło:
Computer Applications in Electrical Engineering; 2011, 9; 213-222
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Introduction to Virtual Phased Arrays for Beamforming Applications
Autorzy:
Comesaña, D. F.
Holland, K. R.
Escribano, D. G.
de Bree, H. E.
Powiązania:
https://bibliotekanauki.pl/articles/176345.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
beamforming
source localization
virtual phased arrays
measurement techniques
Opis:
Sound localization problems are usually tackled by the acquisition of data from phased microphone arrays and the application of acoustic holography or beamforming algorithms. However, the number of sensors required to achieve reliable results is often prohibitive, particularly if the frequency range of interest is wide. It is shown that the number of sensors required can be reduced dramatically providing the sound field is time stationary. The use of scanning techniques such as “Scan & Paint” allows for the gathering of data across a sound field in a fast and efficient way, using a single sensor and webcam only. It is also possible to characterize the relative phase field by including an additional static microphone during the acquisition process. This paper presents the theoretical and experimental basis of the proposed method to localise sound sources using only one fixed microphone and one moving acoustic sensor. The accuracy and resolution of the method have been proven to be comparable to large microphone arrays, thus constituting the so called “virtual phased arrays”.
Źródło:
Archives of Acoustics; 2014, 39, 1; 81-88
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of Distributed Beamforming
Autorzy:
Her, J.
Wysoki, T. A.
Wysoki, B. J.
Powiązania:
https://bibliotekanauki.pl/articles/309541.pdf
Data publikacji:
2011
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
beamforming
distributed antenna array
smart antenna
virtual array
Opis:
As the capabilities of individual nodes in wireless sensor networks increase, so does the opportunity to perform more complicated tasks, such as cooperative distributed beamforming to improve the range of communications and save precious battery power during the transmission.This work presents a review of the current literature focused on implementing distributed beamformers; covering the calculation of ideal beamforming weights, practical considerations such as carrier alignment, smart antennas based on distributed beamformers, and open research problems in the field of distributed beamforming.
Źródło:
Journal of Telecommunications and Information Technology; 2011, 1; 78-88
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave Generation by a Finite Baffle Array in Application to Beam-Forming Analysis
Autorzy:
Tasinkevych, Y.
Powiązania:
https://bibliotekanauki.pl/articles/177857.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
phased array
beamforming
mixed boundary value problem
BIS expansion
Opis:
Directional excitation of sound in an aperiodic finite baffle system is analyzed using a method developed earlier in electrostatics. The solution to the corresponding boundary value problem is obtained in the spatial-frequency domain. The acoustic pressure and normal particle velocity distribution in acoustic media can be easily computed by the inverse Fourier transform from their spatial spectra on the baffle plane. The presented method can be used for linear acoustic phased arrays modeling with finite element size and inter-element interactions taken into account. Some illustrative numerical examples presenting the far-field radiation pattern and wavebeam steering are given.
Źródło:
Archives of Acoustics; 2010, 35, 4; 677-686
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a high-resolution real-time-capable 3D SONAR camera for deep sea operation
Autorzy:
Ehrhardt, M.
Becker, F. J.
Speicher, D.
Fonfara, H.
Hewener, H.
Degel, C.
Tretbar, S.
Powiązania:
https://bibliotekanauki.pl/articles/332135.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
2D array
matrix array
3D imaging
beamforming
Opis:
Within this work we present a first experimental setup of a high-resolution real-timecapable 3D sonar camera system for deep sea operation. Since we are currently in the development process, the focus of this work is on the transmission aspects of the camera. Following publications will include the receiving aspects as well as the first phantom reconstructions. The system consists of a 1024 element matrix array antenna, together with a 128 channel beamforming system including a 1:8 multiplexing device for each channel. The camera is supposed to deliver volumetric images within a range of up to 15 m in a deep sea environment up to 6000 m depth. The antenna provides the advantage of an adjustable defocused transmitting sound field. This allows dynamic control of the field of view, and an increase of the image contrast for a specific region.
Źródło:
Hydroacoustics; 2016, 19; 101-110
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An embedded beamformer for a PID-based trajectory sensing for an autonomous vehicle
Autorzy:
Mvemba, P. K.
Lay-Ekuakille, A.
Kidiamboko, S.
Rahman, M. Z. U.
Powiązania:
https://bibliotekanauki.pl/articles/221802.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autonomous vehicle
beamforming
trajectory follower
ultrasonic obstacle detector
measurement
sensors
Opis:
Beamforming is an advanced signal processing technique used in sensor arrays for directional signal transmission or reception. The paper deals with a system based on an ultrasound transmitter and an array of receivers, to determine the distance to an obstacle by measuring the time of flight and - using the phase beamforming technique to process the output signals of receivers for finding the direction from which the reflected signal is received - locates the obstacle. The embedded beam-former interacts with a PID-based line follower robot to improve performance of the line follower navigation algorithm by detecting and avoiding obstacles. The PID (proportional-integral-derivative) algorithm is also typically used to control industrial processes. It calculates the difference between a measured value and a desired set of points, then attempts to minimize the error by adjusting the output. The overall navigation system combines a PID-based trajectory follower with a spatial-temporal filter (beamformer) that uses the output of an array of sensors to extract signals received from an obstacle in a particular direction in order to guide an autonomous vehicle or a robot along a safe path.
Źródło:
Metrology and Measurement Systems; 2018, 25, 3; 561-575
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new mutual coupling compensation method for receiving antenna array-based DOA estimation
Autorzy:
Parhizgar, N.
Powiązania:
https://bibliotekanauki.pl/articles/141040.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna array
beamforming
compensation matrix
DOA estimation
mutual coupling
MUSIC algorithm
Opis:
Most receiving antenna arrays suffer from the mutual coupling problem between antenna elements, which can critically influence the performance of the array. In this work, a novel and accurate form of compensation matrix is applied to compensate the mutual coupling in a uniform linear array (ULA). This is achieved by applying a new method based on solving a boundary value problem for the whole ULA. In this method, both self and mutual impedances are exploited in an accurate characterization of mutual impedance matrix which results in a perfect mutual coupling compensation method, and hence a very accurate direction of arrival (DOA) estimation. In the new scheme, the compensation matrix is obtained by using the relationship between measured voltage and theoretical coupled voltage based on the MOM. Numerical results show that using DOA estimation algorithms to the decoupled voltage obtained by using this method leads to an excellent performance of DOA estimation with higher accuracy and resolution.
Źródło:
Archives of Electrical Engineering; 2018, 67, 2; 419--431
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy Logic Based Intelligent Data Sensitive Security Model for Big Data in Healthcare
Autorzy:
Dubey, Somya
Verma, Dhanraj
Powiązania:
https://bibliotekanauki.pl/articles/2055246.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microstrip patch
adaptive antennas
parabolic reflector
beamforming
antenna arrays
smart antenna
Opis:
An intelligent security model for the big data environment is presented in this paper. The proposed security framework is data sensitive in nature and the level of security offered is defined on the basis of the data secrecy standard. The application area preferred in this work is the healthcare sector where the amount of data generated through the digitization and aggregation of medical equipment’s readings and reports is huge. The handling and processing of this great amount of data has posed a serious challenge to the researchers. The analytical outcomes of the study of this data are further used for the advancement of the medical prognostics and diagnostics. Security and privacy of this data is also a very important aspect in healthcare sector and has been incorporated in the healthcare act of many countries. However, the security level implemented conventionally is of same level to the complete data which not a smart strategy considering the varying level of sensitivity of data. It is inefficient for the data of high sensitivity and redundant for the data of low sensitivity. An intelligent data sensitive security framework is therefore proposed in this paper which provides the security level best suited for the data of given sensitivity. Fuzzy logic decision making technique is used in this work to determine the security level for a respective sensitivity level. Various patient attributes are used to take the intelligent decision about the security level through fuzzy inference system. The effectiveness and the efficacy of the proposed work is verified through the experimental study.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 2; 245--250
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
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:
Drivetrain noise of the Gyroplane I-28
Hałas układu napędowego wiatrakowca I-28
Autorzy:
Cieślak, S.
Krzymień, W.
Powiązania:
https://bibliotekanauki.pl/articles/213333.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
gyroplane
noise
acoustic camera
beamforming
propeller noise
wiatrakowiec
hałas
hałas śmigła
Opis:
Gyroplanes, as ultralight aircraft, are popular transport vehicles recently. Ultralight aircraft flights take place at a low altitude – their noise is not without effect on people and nature. The localization of the sources of noise and a possibility to decrease the noise of an gyroplane are described in this paper. The rules of design and exploitation of gyroplanes do not define the limits of emitted noise. Gyroplanes are not noisy aircraft vehicles but for their silencing the knowledge about the sources and frequency range of noise is necessary. The goal of the conducted measurement was to determine the gyroplane noise properties and the noise measurement methods. The evaluation of the noise sources was made by acoustic beamforming and the directional emission with single microphones at various engine speeds. The supplement of these tests should be the rotor noise measurement but that investigation should be performed on a special stand, on which the rotor propulsion noise would not disturb the measurement.
Wiatrakowce jako ultralekkie statki latające stają się w ostatnich latach popularnym środkiem transportu. Loty ultralekkich statków powietrznych odbywają się na małych wysokościach – ich hałas nie pozostaje bez wpływu na ludzi i przyrodę. Lokalizacja źródeł hałasu w wiatrakowcu oraz możliwości jego ograniczenia jest przedmiotem niniejszego artykułu. Przepisy budowy i eksploatacji wiatrakowców nie definiują wymagań dotyczących emitowanego hałasu. Wiatrakowce nie należą do najgłośniejszych środków transportu powietrznego lecz wyciszenie wymaga znajomości źródeł hałasu jak i zakresu częstotliwości. Przeprowadzono pomiary mające na celu określenie właściwości akustycznych jak i przyjęcia metodyki pomiarów akustycznych wiatrakowców. Ocenę źródeł hałasu wykonano przy pomocy tzw. akustycznego beamforming’u a rozkład emisji pojedynczymi mikrofonami przy różnych prędkościach obrotowych silnika. Uzupełnieniem tych badań był pomiar hałasu wirnika jednak badania takie przeprowadzono na specjalnym stanowisku, by hałas napędu wirnika nie zakłócał pomiarów.
Źródło:
Prace Instytutu Lotnictwa; 2018, 1 (250); 7-15
0509-6669
2300-5408
Pojawia się w:
Prace Instytutu Lotnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid adaptive beamforming approach for antenna array fed parabolic reflector for C-band applications
Autorzy:
Bawane, Sheetal
Kumar Panda, Debendra
Powiązania:
https://bibliotekanauki.pl/articles/27314230.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
microstrip patch
adaptive antennas
parabolic reflector
beamforming
antenna arrays
smart antenna
Opis:
This paper presents the design of a parabolic reflector fed through a patch antenna array feed to enhance its directivity and radiation properties. Adaptive beam for‐ mers steer and alter an array’s beam pattern to increase signal reception and minimize interference. Weight selec‐ tion is a critical difficulty in achieving low SLL and beam width. Low Side Lobe Level [SLL]and narrow beam reduce antenna radiation and reception. Adjusting the weights reduces SLL and tilts the nulls. Adaptive beam formers are successful signal processors if their array output con‐ verges to the required signal. Smart antenna weights can be determined using any window function. Half Power Beam Width and SLL could be used to explore different algorithms. Both must be low for excellent smart antenna performance. In noisy settings, ACLMS and CLMS create narrow beams and side lobes. AANGD offers more control than CLMS and ACLMS. The blend of CLMS and ACLMS is more effective at signal convergence than CLMS and AANGD. It presents an alternative to the conventionally used horn‐based feed network for C‐band applications such as satellite communication. Broadside radiation patterns and 4x4 circular patch antenna arrays are used in the proposed design. 1400 aperture illumination is pro‐ vided by the array’s feed parabolic reflector, whose F/D ratio is 0.36. The proposed design’s efficacy is assessed using simulation analysis.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2023, 17, 1; 45--50
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
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