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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
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