dr hab. inż. Jurij Tasinkiewicz 

Doktorat
2004  Numerical efficiency of interdigital transducer charge spatial spectrum evaluation methods
 578 
Habilitacja
20140130  Electrostatic methods in analysis of acoustic beamforming structures 
Promotor prac doktorskich
1.  20171130  Karwat Piotr  Numeryczna rekonstrukcja pola prędkości fali akustycznej na podstawie analizy sygnałów ultradźwiękowych  1291 
Ostatnie publikacje
1.  Tasinkevych Y., Podhajecki J., Falińska K., Litniewski J., Simultaneous estimation of cortical bone thickness and acoustic wave velocity using a multivariable optimization approach: Bone phantom and invitro study, Ultrasonics, ISSN: 0041624X, DOI: 10.1016/j.ultras.2015.10.013, Vol.65, pp.105112, 2016 Streszczenie: The paper presents a method that allows the thickness of a compact bone layer and longitudinal wave velocity in the bone to be determined simultaneously with the use of reflected waves, with particular emphasis on the case of layers when the propagation time through the layer is shorter than the time duration of the interrogating pulse. Słowa kluczowe: Bone quantitative ultrasound, Human cortical bone, Human cancellous bone, Ultrasound attenuation, Layered media Afiliacje autorów:
 30p.  
2.  Trots I., Tasinkevych Y., Nowicki A., Orthogonal Golay Codes With Local Beam Pattern Correction in Ultrasonic Imaging, IEEE SIGNAL PROCESSING LETTERS, ISSN: 10709908, DOI: 10.1109/LSP.2015.2423619, Vol.22, No.10, pp.16811684, 2015 Streszczenie: The goal of this study is to improve the synthetic transmit aperture (STA) imaging method by employing the transducer array element beam pattern correction combined with emission of mutually orthogonal complementary Golay sequences. The transmitreceive scheme based on simultaneous emission of different Golay pairs by adjacent transmit subapertures is implemented to decrease the image reconstruction time. A brief discussion on the fundamentals of the orthogonal Golay complementary sequences is provided and their advantages for the STA imaging method are demonstrated. The performance of the developed approach was tested using FIELD II simulated synthetic aperture data from the point reflectors, which allowed to estimate both; the penetration depth and the lateral resolution. In the work the 128 element, 5 MHz, linear array transducer was used. The obtained results showed that the applying the beam pattern correction leads to the image quality improvement in the vicinity of the transducer face. Specifically, the noise level evaluated between the point reflectors at the depth of 4 mm decreased from  14.1 dB for the case of omnidirectional source to  38.7 dB when the element beam pattern correction was implemented. The simulation proved that the overall imaging quality was improved considerably. Słowa kluczowe: coded excitation, element directivity, mutually orthogonal Golay codes, synthetic aperture, ultrasound imaging Afiliacje autorów:
 30p.  
3.  Tasinkevych Y., Podhajecki J., Wójcik J., Falińska K., Litniewski J., Estimation of layer thickness by the cost function optimization: phantom study, HYDROACOUSTICS, ISSN: 16421817, Vol.18, pp.161166, 2015 Streszczenie: The aim of this work is to present preliminary results of the layer thickness assessment method based on optimization approach. The developed method is based on a multilayer model structure. The measured acoustic signal reflected from the layer is compared with a simulated signal on the basis of a multilayer model. The cost function is defined as the difference between the reflected signal measured using pulse echo approach and the simulated signal. The thickness of the solid layer is the parameter which minimizes the cost function yielding desired solution. Minimization of the cost function is performed with the simulated annealing algorithm. The results obtained with the developed method using measurement data of a custom design model are compared with the reference value and the accuracy of the method is checked. The relative error of the thickness estimation is 1.44 %. Słowa kluczowe: Bone quantitative ultrasound, Human cortical bone, Human cancellous bone, Ultrasound attenuation, Layered media Afiliacje autorów:
 6p.  
4.  Tasinkevych Y., Trots I., Circular Radon Transform Inversion Technique in Synthetic Aperture Ultrasound Imaging: an Ultrasound Phantom Evaluation, ARCHIVES OF ACOUSTICS, ISSN: 01375075, DOI: 10.2478/aoa20140061, Vol.39, No.4, pp.569582, 2014 Streszczenie: 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 xray computer tomography is demonstrated. The methods employing Radon transform were previously extensively explored in the synthetic aperture radars, geophysics, and medical imaging using xray computer tomography. In this paper the main attention is paid to the ultrasound imaging employing monostatic transmitreceive configuration. Specifically, a single transmit and receive omnidirectional source placed at the same spatial location is used for generation of a wideband ultrasound pulse and detection of backscattered waves. The paper presents derivation of the closedform solution of the CRT inversion algorithms by two different approaches: the rangemigration algorithm (RMA) and the deconvolution algorithm (DA). Experimentally determined data of ultrasound phantom obtained using a 32element 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. Słowa kluczowe: synthetic aperture focusing method, circular Radon Transform, delayandsum beamforming, range migration algorithm Afiliacje autorów:
 15p.  
5.  Falińska K., Litniewski J., Tasinkevych Y., Assesment of cortical bone thickness using cepstrum analysis. Simulation study, HYDROACOUSTICS, ISSN: 16421817, Vol.17, pp.4756, 2014 Streszczenie: Assessment of cortical bone thickness is important from a medical point of view because bonelayer thickness has a diagnostic value. The thinning of the cortical bone layer reduces the mechanical strength of the bone and exposes it to an increased risk of osteoporotic fractures [1]. The hip bone (proximal femur) is the most critical fracture site. The thickness of the cortical layer in the proximal femur is often too thin to be detected from ultrasonic echoes using traditional peak detection methods (for example the envelope method). In such a case the cepstrum analysis technique may be very useful. In this study the cepstrum method was applied to analyze numerically simulated echoes reflected from the layer and to determine layer thickness. In simulation, the transducer operated at 1 MHz and pulses of a 1.5 microsec. duration were assumed. Słowa kluczowe: cortical bone, thickness, cepstrum analysis Afiliacje autorów:
 7p.  
6.  Tasinkevych Y., SingleCrystal Kerfless 2D Array Transducer for Volumetric Medical Imaging: Theoretical Study, World Academy of Science, Engineering and Technology, International Journal of Electrical, Computer, Electronics and Communication Engineering, ISSN: 2010376X, Vol.8, No.11, pp.15661573, 2014 Streszczenie: The aim of this work is to present a theoretical analysis of a 2D ultrasound transducer comprised of crossed arrays of metal strips placed on both sides of thin piezoelectric layer (a). Such a structure is capable of electronic beamsteering of generated wavebeam both in elevation and azimuth. In this paper a semianalytical model of the considered transducer is developed. It is based on generalization of the wellknown BISexpansion method. Specifically, applying the electrostatic approximation, the electric field components on the surface of the layer are expanded into fast converging series of double periodic spatial harmonics with corresponding amplitudes represented by the properly chosen Legendre polynomials. The problem is reduced to numerical solving of certain system of linear equations for unknown expansion coefficients. Słowa kluczowe: beamforming, transducer array, BISexpansion Afiliacje autorów:
 
7.  Danicki E.J., Nowicki A., Tasinkevych Y., Interdigitated Interdigital Transducer for Surface Elastometry of Soft Damping Tissue, IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, ISSN: 08853010, DOI: 10.1109/TUFFC.2013.2690, Vol.60, No.6, pp.12601262, 2013 Streszczenie: Measurement of the shear elastic constant of soft and highly damping tissue of high Poisson ratio is quite a challenging task. It is proposed to evaluate shear wave velocity and damping of tissue by measuring the shear skimming bulk waves using one interdigitated interdigital transducer on a piezoelectric layer, such as polyvinylidene fluoride, applied to the surface of the small tissue sample. Słowa kluczowe: Interdigital transducer, surface acoustic waves, electrostatics, mixed boundaryvalue problem Afiliacje autorów:
 35p.  
8.  Tasinkevych Y., Klimonda Z., Lewandowski M., Nowicki A., Lewin P.A.^{♦}, Modified multielement synthetic transmit aperture method for ultrasound imaging: A tissue phantom study, Ultrasonics, ISSN: 0041624X, DOI: 10.1016/j.ultras.2012.10.001, Vol.53, pp.570579, 2013 Streszczenie: The paper presents the modified multielement synthetic transmit aperture (MSTA) method for ultrasound imaging. It is based on coherent summation of RF echo signals with apodization weights taking into account the finite size of the transmit subaperture and of the receive element. The work presents extension of the previous study where the modified synthetic transmit aperture (STA) method was considered and verified [1]. In the case of MSTA algorithm the apodization weights were calculated for each imaging point and all combinations of the transmit subaperture and receive element using their angular directivity functions (ADFs). The ADFs were obtained from the exact solution of the corresponding mixed boundaryvalue problem for periodic baffle system modeling the transducer array. Performance of the developed method was tested using Field II simulated synthetic aperture data of point reflectors for 4 MHz 128element transducer array with 0.3 mm pitch and 0.02 mm kerf to estimate the visualization depth and lateral resolution. Also experimentally determined data of the tissuemimicking phantom (Dansk Fantom Service, model 571) obtained using 128 elements, 4 MHz, linear transducer array (model L145/38) and Ultrasonix SonixTOUCH Research platform were used for qualitative assessment of imaging contrast improvement. Comparison of the results obtained by the modified and conventional MSTA algorithms indicated 15 dB improvement of the noise reduction in the vicinity of transducer’s surface (1 mm depth), and concurrent increase in the visualization depth (86% augment of the scattered amplitude at the depth of 90 mm). However, this increase was achieved at the expense of minor degradation of the lateral resolution of approximately 8% at the depth of 50 mm and 5% at the depth of 90 mm. Słowa kluczowe: Synthetic aperture imaging, Ultrasound imaging, Directivity function, Beamforming Afiliacje autorów:
 35p.  
9.  Tasinkevych Y., Danicki E.J., Theoretical Analysis of a CrossedElectrode 2D Array for 3D Imaging, World Academy of Science, Engineering and Technology, International Journal of Medical Science and Engineering, ISSN: 2010376X, Vol.7, No.11, pp.340344, 2013 Streszczenie: Planar systems of electrodes arranged on both sides of dielectric piezoelectric layer are applied in numerous transducers. They are capable of electronic beamsteering of generated wave both in azimuth and elevation. The wavebeam control is achieved by addressable driving of twodimensional transducer through proper voltage supply of electrodes on opposite surfaces of the layer. In this paper a semianalytical method of analysis of the considered transducer is proposed, which is a generalization of the wellknown BISexpansion method. It was earlier exploited with great success in the theory of interdigital transducers of surface acoustic waves, theory of elastic wave scattering by cracks and certain advanced electrostatic problems. The corresponding nontrivial electrostatic problem is formulated and solved numerically Słowa kluczowe: beamforming, transducer array, BISexpansion Afiliacje autorów:
 
10.  Danicki E.J., Tasinkevych Y., Electrostatics of Planar Multielectrode Sensors with Application to Surface Elastometry, SENSORS, ISSN: 14248220, Vol.12, pp.1194611956, 2012 Streszczenie: Systems of planar electrodes arranged on dielectric or piezoelectric layers are applied in numerous sensors and transducers. In this paper electrostatics of such electrode systems is presented and exploited in the analysis of distributed piezoelectric transducer dedicated to surface elastometry of biological tissues characterized by large Poisson modulus. The fundamental Matlab code for analyzing complex planar multiperiodic electrode systems is also presented. Słowa kluczowe: interdigital transducer, surface elastometry, BISexpansion Afiliacje autorów:
 25p.  
11.  Tasinkevych Y., Trots I., Nowicki A., Lewin P.A.^{♦}, Modified synthetic transmit aperture algorithm for ultrasound imaging, Ultrasonics, ISSN: 0041624X, DOI: 10.1016/j.ultras.2011.09.003, Vol.52, pp.333342, 2012 Streszczenie: The modified synthetic transmit aperture (STA) algorithm is described. The primary goal of this work was to assess the possibility to improve the image quality achievable using synthetic aperture (SA) approach and to evaluate the performance and the clinical applicability of the modified algorithm using phantoms. The modified algorithm is based on the coherent summation of backscattered RF echo signals with weights calculated for each point in the image and for all possible combinations of the transmit–receive pairs. The weights are calculated using the angular directivity functions of the transmit–receive elements, which are approximated by a farfield radiation pattern of a narrow strip transducer element vibrating with uniform pressure amplitude over its width. In this way, the algorithm takes into account the finite aperture of each individual element in the imaging transducer array. The performance of the approach developed was tested using FIELD II simulated synthetic aperture data of the point reflectors, which allowed the visualization (penetration) depth and lateral resolution to be estimated. Also, both simulated and measured data of cyst phantom were used for qualitative assessment of the imaging contrast improvement. The experimental data were obtained using 128 elements, 4 MHz, linear transducer array of the Ultrasonix research platform. The comparison of the results obtained using the modified and conventional (unweighted) STA algorithms revealed that the modified STA exhibited an increase in the penetration depth accompanied by a minor, yet discernible upon the closer examination, degradation in lateral resolution, mainly in the proximity of the transducer aperture. Overall, however, a considerable (12 dB) improvement in the image quality, particularly in the immediate vicinity of the transducer’s surface was demonstrated. The modified STA method holds promise to be of clinical importance, especially in the applications where the quality of the ‘‘nearfield’’ image, that is the image in the immediate vicinity of the scanhead is of critical importance such as for instance in skin and breastexaminations. Słowa kluczowe: synthetic aperture imaging, ultrasound imaging, directivity function, beamforming Afiliacje autorów:
 25p.  
12.  Tasinkevych Y., Trots I., Nowicki A., Lewandowski M., Optimization of the Multielement Synthetic Transmit Aperture Method for Medical Ultrasound Imaging Applications, ARCHIVES OF ACOUSTICS, ISSN: 01375075, Vol.37, No.1, pp.4755, 2012 Streszczenie: The paper presents the optimization problem for the multielement synthetic transmit aperture method (MSTA) in ultrasound imaging applications. The optimal choice of the transmit aperture size is made as a tradeoff 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 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. Słowa kluczowe: ultrasound imaging, synthetic aperture, beamforming Afiliacje autorów:
 15p.  
13.  Tasinkevych Y., Trots I., Nowicki A., Lewandowski M., Transmit Subaperture Optimization in MSTA Ultrasound Imaging Method, World Academy of Science, Engineering and Technology, ISSN: 2010376X, Vol.65, pp.422427, 2012 Streszczenie: The paper presents the optimization problem for the multielement synthetic transmit aperture method (MSTA) in ultrasound imaging applications. The optimal choice of the transmit aperture size is performed as a tradeoff between the lateral resolution, penetration depth and the frame rate. Results of the analysis obtained by a developed optimization algorithm are presented. Maximum penetration depth and the best lateral resolution at given depths are chosen as the optimization criteria. The optimization algorithm was tested using synthetic aperture data of point reflectors simulated by Filed II program for Matlab® for the case of 5MHz 128element linear transducer array with 0.48 mm pitch are presented. The visualization of experimentally obtained synthetic aperture data of a tissue mimicking phantom and in vitro measurements of the beef liver are also shown. The data were obtained using the SonixTOUCH Research systemequipped with a linear 4MHz 128 element transducerwith 0.3 mm element pitch, 0.28 mm element width and 70% fractional bandwidth was excited by one sine cycle pulse burst of transducer's center frequency. Słowa kluczowe: synthetic aperture method, ultrasound imaging, beamforming Afiliacje autorów:
 
14.  Trots I., Tasinkevych Y., Nowicki A., Lewandowski M., Coded Transmission in Synthetic Transmit Aperture Ultrasound Imaging Method, World Academy of Science, Engineering and Technology, ISSN: 2010376X, Vol.63, pp.331336, 2012 Streszczenie: The paper presents the study of synthetic transmit aperture method applying the Golay coded transmission for medical ultrasound imaging. Longer coded excitation allows to increase the total energy of the transmitted signal without increasing the peak pressure. Signaltonoise ratio and penetration depth are improved maintaining high ultrasound image resolution. In the work the 128element linear transducer array with 0.3 mm interelement spacing excited by one cycle and the 8 and 16bit Golay coded sequences at nominal frequencies 4 MHz was used. Single element transmission aperture was used to generate a spherical wave covering the full image region and all the elements received the echo signals. The comparison of 2D ultrasound image s of the wire phantom as well as of the tissue mimicking phantom is presented to demonstrate the benefits of the coded transmission. The results were obtained using the synthetic aperture algorithm with transmit and receive signals correction based on a single element directivity function Słowa kluczowe: Golay coded sequences, radiation pattern, synthetic aperture, ultrasound imaging Afiliacje autorów:
 
15.  Trots I., Tasinkevych Y., Nowicki A., Lewandowski M., In Vitro Study of Coded Transmission in Synthetic Aperture Ultrasound Imaging Systems, World Academy of Science, Engineering and Technology, ISSN: 2010376X, Vol.6, No.6, pp.8287, 2012 Streszczenie: In the paper the study of synthetic transmit aperture method applying the Golay coded transmission for medical ultrasound imaging is presented. Longer coded excitation allows to increase the total energy of the transmitted signal without increasing the peak pressure. Moreover signaltonoise ratio and penetration depth are improved while maintaining high ultrasound image resolution. In the work the 128element linear transducer array with 0.3 mm interelement spacing excited by one cycle and the 8 and 16 bit Golay coded sequences at nominal frequency 4 MHz was used. To generate a spherical wave covering the full image region a single element transmission aperture was used and all the elements received the echo signals. The comparison of 2D ultrasound images of the tissue mimicking phantom and in vitro measurements of the beef liver is presented to illustrate the benefits of the coded transmission. The results were obtained using the synthetic aperture algorithm with transmit and receive signals correction based on a single element directivity function. Słowa kluczowe: Golay coded sequences, radiation pattern, signal, processing, synthetic aperture, ultrasound imaging Afiliacje autorów:
 
16.  Tasinkevych Y., Danicki E.J., Wave generation and scattering by periodic baffle system in application to beamforming analysis, WAVE MOTION, ISSN: 01652125, DOI: 10.1016/j.wavemoti.2010.10.002, Vol.48, pp.130145, 2011 Streszczenie: Directional excitation and detection of sound in the periodic baffle system are analyzed using the method developed earlier in electrostatics. The phenomenon is exploited in phased array transducers applied in ultrasonography, nondestructive evaluation and testing. The nice feature of the applied method is that the matrices of the resulting system of the equations are relatively easy for computations and that the results satisfy exactly the energy conservation law. Illustrative numerical examples present the farfield wavebeam steering generated in a baffle system that may be considered as a model of a linear ultrasonic transducer array. Słowa kluczowe: Phased array transducers, Bragg scattering, BISexpansion Afiliacje autorów:
 30p.  
17.  Tasinkevych Y., Electromagnetic scattering by periodic grating of PEC bars, JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, ISSN: 09205071, Vol.25, pp.641650, 2011  20p.  
18.  Trots I., Tasinkevych Y., Nowicki A., Lewandowski M., Golay Coded Sequences in Synthetic Aperture Imaging Systems, ARCHIVES OF ACOUSTICS, ISSN: 01375075, Vol.36, No.4, pp.913926, 2011 Streszczenie: 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 signaltonoise ratio and increase the visualization depth maintaining the ultrasound image resolution. Słowa kluczowe: ultrasound imaging, synthetic aperture, beamforming, radiation pattern, coded sequences, Golay codes Afiliacje autorów:
 15p.  
19.  Trots I., Tasinkevych Y, Nowicki A., Lewandowski M., MultiElement Synthetic Transmit Aperture Method in Medical Ultrasound Imaging, World Academy of Science, Engineering and Technology, ISSN: 2010376X, Vol.80, pp.562567, 2011 Streszczenie: The paper presents the multielement synthetic transmit aperture (MSTA) method with a small number of elements transmitting and all elements receiving apertures in medical ultrasound imaging. Compared to other methods the MSTA allows to increase the system frame rate and provides the best compromise between penetration depth and lateral resolution. Słowa kluczowe: beamforming, frame rate, synthetic aperture, ultrasound imaging Afiliacje autorów:
 
20.  Trots I., Nowicki A., Lewandowski M., Tasinkevych Y., Multielement synthetic transmit aperture in medical ultrasound imaging, ARCHIVES OF ACOUSTICS, ISSN: 01375075, Vol.35, No.4, pp.687699, 2010 Streszczenie: 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 multielement 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 32element 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. Słowa kluczowe: ultrasound imaging, synthetic aperture, beamforming Afiliacje autorów:
 9p.  
21.  Tasinkevych Y., Wave Generation by a Finite Baffle Array in Application to BeamForming Analysis, ARCHIVES OF ACOUSTICS, ISSN: 01375075, Vol.35, No.4, pp.677686, 2010 Streszczenie: Directional excitation of sound in an aperiodic finite baffle system is analyzed using a method developed earlier in electrostatics. Słowa kluczowe: phased array, beamforming, mixed boundaryvalue problem, BISexpansion Afiliacje autorów:
 9p.  
22.  Tasinkevych Y., Danicki E.J., Fullwave Analysis of Periodic Baffle System in Beamforming Applications, ARCHIVES OF ACOUSTICS, ISSN: 01375075, Vol.35, No.4, pp.661675, 2010 Streszczenie: Mixed boundaryvalue problem for periodic baffles in acoustic medium is solved with help of the method developed earlier in electrostatics. The nice feature of the method is that the resulting matrices are relatively easy for computations and that the results satisfy exactly the energy conservation law. Illustrative numerical examples present the wavebeam steering (in the farfield) in a baffle system that may be considered as a model of onedimensional ultrasonic transducer array. Słowa kluczowe: Sound field calculation, linear phased arrays, BIS expansion, farfield radiation pattern, beamsteering, transducer arrays, composite transducers, scattering, generation, fields Afiliacje autorów:
 9p.  
23.  Tasinkevych Y., EM scattering by the parallel plate waveguide array with thick walls for oblique incidence, JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, ISSN: 09205071, DOI: 10.1163/156939309789476437, Vol.23, pp.16111621, 2009 Streszczenie: A problem of electromagnetic wave scattering by a periodic parallelplate waveguide array is studied in the paper. The scattered field above the waveguides is sought in the form of a series of spatial harmonics in accordance with the Floquet's theorem, whereas in the waveguide regions it is sought in the form of parallel plate waveguide modes. A Fourier expansion for spatial harmonics amplitudes with coefficients in the form of properly chosen Legendre functions is used to satisfy the boundary and edge conditions by field components in free space above the array. Some numerical results are given. Afiliacje autorów:
 32p.  
24.  Tasinkevych Y., Electromagnetic scattering by a periodic array of thickwalled parallel plate waveguides, JOURNAL OF TECHNICAL PHYSICS, ISSN: 03248313, Vol.50, No.1, pp.4153, 2009  6p.  
25.  Tasinkevych Y., Scattering of Hpolarized wave by a periodic array of thickwalled parallel plate waveguides, IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, ISSN: 0018926X, Vol.56, pp.33333337, 2008  
26.  Danicki E.J., Tasinkevych Y., Nonstandard electrostatic problem for strips, JOURNAL OF ELECTROSTATICS, ISSN: 03043886, DOI: 10.1016/j.elstat.2005.09.007, Vol.64, pp.386391, 2006 Streszczenie: The spatial field distribution is the most frequent subject of standard electrostatic analysis. In this paper the system of several strips in external spatialharmonic electric field, which causes the charge distribution on them, is considered. The solution is constructed as a linear combination of certain template functions, evaluated in spectral domain and satisfying the electric boundary conditions on the strips. The problem is analogous to wave scattering; this justifies the application of the wavescattering terminology (i.e. incident wave for the external field and the corresponding ‘radiation condition’) in the considered nonstandard ‘electrostatic scattering’ problem. The strip total charge and the Bloch harmonics of the ‘scattered’ field are evaluated. Słowa kluczowe: Planar electrodes, Interdigital transducers, EM scattering Afiliacje autorów:
 
27.  Tasinkevych Y., Danicki E.J., On electrostatics of finite planar systems of strips applied in surface acoustic wave interdigital transducers, JOURNAL OF TECHNICAL PHYSICS, ISSN: 03248313, Vol.49, No.3, pp.175193, 2005 
Lista ostatnich monografii
1. 310  Tasinkevych Y., Electrostatic methods in analysis of acoustic beamforming structures, IPPT Reports on Fundamental Technological Research, 3, pp.1159, 2012 
Lista rozdziałów w ostatnich monografiach
1. 558  Tasinkiewicz J. , Advances in Medicine and Biology, rozdział: 3D Ultrasonography in Real Time: Image Reconstruction Methods, Nova Science Publishers, Inc., New York, pp.87122, 2017 
2. 262  Danicki E.J., Tasinkevych Y., Acoustical Imaging, rozdział: BeamForming Electrostrictive Matrix, Springer, Nowicki A., Litniewski J., Kujawska T. (Eds.), 31, pp.363369, 2012 
3. 263  Trots I., Tasinkevych Y., Nowicki A., Acoustical Imaging, rozdział: Coded Excitation with Directivity Correction in Synthetic Aperture Imaging System, Springer, Nowicki A., Litniewski J., Kujawska T. (Eds.), 31, pp.157167, 2012 
4. 306  Tasinkevych Y., Klimonda Z., Lewandowski M., Nowicki A., Acoustical Imaging, rozdział: Sound Field Directivity Correction in Synthetic Aperture Algorithm for Medical Ultrasound, Springer, Nowicki A., Litniewski J., Kujawska T. (Eds.), 31, pp.169179, 2012 
5. 308  Tasinkevych Y., Trots I., Nowicki A., Acoustical Imaging, rozdział: Optimization in the multielement synthetic transmit aperture method for ultrasound imaging, Springer, Nowicki A., Litniewski J., Kujawska T. (Eds.), pp.147156, 2012 
6. 254  Trots I., Nowicki A., Lewandowski M., Tasinkevych Y., Ultrasound Imaging, rozdział: Synthetic Aperture Method in Ultrasound Imaging, Masayuki Tanabe, pp.3756, 2011 
7. 309  Tasinkevych Y., Electrostatics: Theory and Applications, rozdział: Electrostatics of planar system of conducting strips, Nova Science Publishers Inc., pp.189221, 2011 
Prace konferencyjne
1.  Litniewski J., Tasinkevych Y., Podhajecki J., Falińska K., Combined estimation of thickness and velocity of cortical shell using reflected waves: study on bone phantoms and samples, IUS 2015, IEEE International Ultrasonics Symposium, 20151021/1024, Taipei (TW), DOI: 10.1109/ULTSYM.2015.0512, pp.14, 2015 Streszczenie: Estimation of the thickness and sound velocity of cortical bone is important per se as well as for correcting measurements of cancellous bone properties. We propose a method that allows the thickness of a compact bone layer and longitudinal wave velocity in the bone to be determined simultaneously with the use of the reflected waves, with particular emphasis on the 1mm  3mm thick bone layers corresponding to the thickness of the cortex of the human femur. The method was tested using ultrasonic data obtained from cortical bone phantoms and a fresh calf bone specimen. The results show that the method seems to be well suited to be employed for the determination of the thickness and acoustic wave velocity of the cortical bone layer. Słowa kluczowe: Cortical bone, trabecular bone, thickness and velocities of cortical shell, reflected waves, BUA Afiliacje autorów:
 
2.  Tasinkevych Y., Klimonda Z., Lewandowski M., Trots I., Nowicki A., Sound field directivity in multielement synthetic transmit aperture method for ultrasound imaging, Conference on Medical Imaging  Physics of Medical Imaging, 20120205/0208, San Diego (US), DOI: 10.1117/12.910584, Vol.8313, pp.8313691, 2012 Streszczenie: A modified multielement synthetic transmit aperture (MSTA) method for ultrasound imaging with RF echoes correction taking into account the influence of the element directivity is presented. The property is significant as the element width becomes commensurable with the wavelength of the emitted signal. The angular dependence of the radiation efficiency of the transmit/receive aperture is obtained from exact solution of the corresponding mixed boundaryvalue problem for periodic baffle system, modeling the transducer array. It is evaluated at the nominal frequency of the excitation signal and is implemented in the developed MSTA algorithm as apodization weights calculated for each imaging point and all combinations of the transmit/receive apertures. The performance of developed method is tested using FIELDII simulated synthetic aperture data of the point reflectors to estimate the visualization depth and lateral resolution. Besides, a FIELDII simulated and measurement data of cyst phantom are used for qualitative assessment of the imaging contrast. Comparison of the results obtained by the modified and conventional MSTA algorithms is given which reveals considerable improvement of the image quality in the area neighboring to the transducer’s aperture, and increase of the visualization depth at the cost of slight degradation of lateral resolution near the transducer face. Słowa kluczowe: synthetic aperture, ultrasound imaging, beamforming Afiliacje autorów:
 
3.  Trots I., Tasinkevych Y., Nowicki A., Lewandowski M., Golay coded sequences in synthetic aperture imaging systems, 58 Otwarte Seminarium z Akustyki, 20110813/0816, Jurata (PL), pp.347357, 2011 Streszczenie: 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 signaltonoise ratio and increase the visualization depth maintaining the ultrasound image resolution. Słowa kluczowe: Golay codes, coded sequences, synthetic aperture, ultrasound imaging Afiliacje autorów:
 
4.  Tasinkevych Y., Trots I., Nowicki A., Lewandowski M., Optimal aperture in MSTA method for medical ultrasound imaging applications, 58 Otwarte Seminarium z Akustyki, 20110813/0816, Jurata (PL), pp.323334, 2011  
5.  Tasinkevych Y., Fullwave analysis of finite baffle system for linear phased array applications, 57 Otwarte Seminarium z Akustyki, 20100920/0924, Gliwice (PL), pp.201204, 2010  
6.  Trots I., Nowicki A., Lewandowski M., Tasinkevych Y., Multielement synthetic transmit aperture in medical ultrasound imaging, 57 Otwarte Seminarium z Akustyki, 20100920/0924, Gliwice (PL), pp.205208, 2010 Streszczenie: Synthetic aperture (SA) technique is a novel approach to today's 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. Słowa kluczowe: synthetic aperture, ultrasound imaging Afiliacje autorów:
 
7.  Tasinkevych Y., Nowicki A., Trots I., Element directivity influence in the synthetic focusing algorithm for ultrasound imaginig, 57 Otwarte Seminarium z Akustyki, 20100920/0924, Gliwice (PL), pp.197200, 2010 