Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0618
N. Thong-un, Y. Orino, M. Kurosawa, S. Hirata
This paper proposes an ultrasonic system for three-dimensional-positioning measurements. This ultrasonic system consists of one sound transmitter and four receivers. These devices are available to support the low-cost applications. To satisfy real-time signal processing, an echo is converted to a digital one-bit stream by a four-channel delta-sigma- modulation board. Then, FPGA is mentioned for cross-correlation based on one-bit signal processing. The object location is computed according to the distance from the sound source to an object, the angle of elevation, and the angle of azimuth. A spherical object is considered as a target of this system. The validity of experimental results is evaluated under statistics.
{"title":"Three-dimensional-positioning measurements based on echolocation using linear-period-modulated ultrasonic signal","authors":"N. Thong-un, Y. Orino, M. Kurosawa, S. Hirata","doi":"10.1109/ULTSYM.2014.0618","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0618","url":null,"abstract":"This paper proposes an ultrasonic system for three-dimensional-positioning measurements. This ultrasonic system consists of one sound transmitter and four receivers. These devices are available to support the low-cost applications. To satisfy real-time signal processing, an echo is converted to a digital one-bit stream by a four-channel delta-sigma- modulation board. Then, FPGA is mentioned for cross-correlation based on one-bit signal processing. The object location is computed according to the distance from the sound source to an object, the angle of elevation, and the angle of azimuth. A spherical object is considered as a target of this system. The validity of experimental results is evaluated under statistics.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124986409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0325
Yuexin Guo, Wei-Ning Lee
Strain compounding has been previously developed as an approach to reducing speckle noise. The technique is based on speckle de-correlation induced by different strain levels applied on the medium and has been demonstrated feasible in the human superficial soft tissues under external quasi-static compression. In this study, the efficacy of strain compounding in echocardiography was investigated. A temporal gate in a cardiac cycle was first defined, with the middle echocardiographic frame selected as the reference image. The in-plane motion of the temporally gated images was then estimated and used for image correction with respect to the reference frame. Finally, the spatially matched images were averaged to form a speckle reduced image. Not only did the prerequisite deformation stem from the natural contraction of the heart, but the computational efficiency could also remain by simply using the strain estimates yielded from cardiac strain imaging, which has become a commonly used tool in the clinic. Ultrasonic images of a normal human heart over six cardiac cycles were acquired by a commercial ultrasound imaging system at a frame rate of 70 fps in the apical four-chamber, long-axis and short-axis views. The results show approximately 7.9%, 8.4%, and 11.3% improvements in the signal-to-noise ratio (SNR) of the septal wall segment of the strain-compounded images in the apical four-chamber and long-axis views, respectively. Comparable performance of strain compounding to that of a well-established method, Speckle Reducing Anisotropic Diffusion (SRAD), was also observed.
{"title":"On the feasibility of speckle reduction in echocardiography using strain compounding","authors":"Yuexin Guo, Wei-Ning Lee","doi":"10.1109/ULTSYM.2014.0325","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0325","url":null,"abstract":"Strain compounding has been previously developed as an approach to reducing speckle noise. The technique is based on speckle de-correlation induced by different strain levels applied on the medium and has been demonstrated feasible in the human superficial soft tissues under external quasi-static compression. In this study, the efficacy of strain compounding in echocardiography was investigated. A temporal gate in a cardiac cycle was first defined, with the middle echocardiographic frame selected as the reference image. The in-plane motion of the temporally gated images was then estimated and used for image correction with respect to the reference frame. Finally, the spatially matched images were averaged to form a speckle reduced image. Not only did the prerequisite deformation stem from the natural contraction of the heart, but the computational efficiency could also remain by simply using the strain estimates yielded from cardiac strain imaging, which has become a commonly used tool in the clinic. Ultrasonic images of a normal human heart over six cardiac cycles were acquired by a commercial ultrasound imaging system at a frame rate of 70 fps in the apical four-chamber, long-axis and short-axis views. The results show approximately 7.9%, 8.4%, and 11.3% improvements in the signal-to-noise ratio (SNR) of the septal wall segment of the strain-compounded images in the apical four-chamber and long-axis views, respectively. Comparable performance of strain compounding to that of a well-established method, Speckle Reducing Anisotropic Diffusion (SRAD), was also observed.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125861789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0181
J. H. Lee, G. Traverso, Carl M. Schoellhammer, D. Blankschtein, R. Langer, K. Thomenius, D. Boning, B. Anthony
Wireless capsule endoscopy (WCE) has revolutionized the capacity for evaluation of the gastrointestinal (GI) tract. Although WCE provides high quality images of the GI tract, evaluation is limited to the mucosal surface. This work investigates feasibility and design considerations for wireless capsule endoscopic ultrasound (WCEU) that combines the benefits of WCE and ultrasound imaging. This work has two goals: (1) evaluate transducer designs appropriate for WCEU and (2) investigate whether peristalsis can produce sufficient contact to ensure acoustic coupling. Between mechanical scanning (MS) and side-looking array (SLA) designs, MS performs better for both imaging performance and system complexity. In vivo imaging in pigs demonstrates promising results, although the effect of peristalsis and resulting coverage needs further investigation and quantification.
{"title":"Towards wireless capsule endoscopic ultrasound (WCEU)","authors":"J. H. Lee, G. Traverso, Carl M. Schoellhammer, D. Blankschtein, R. Langer, K. Thomenius, D. Boning, B. Anthony","doi":"10.1109/ULTSYM.2014.0181","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0181","url":null,"abstract":"Wireless capsule endoscopy (WCE) has revolutionized the capacity for evaluation of the gastrointestinal (GI) tract. Although WCE provides high quality images of the GI tract, evaluation is limited to the mucosal surface. This work investigates feasibility and design considerations for wireless capsule endoscopic ultrasound (WCEU) that combines the benefits of WCE and ultrasound imaging. This work has two goals: (1) evaluate transducer designs appropriate for WCEU and (2) investigate whether peristalsis can produce sufficient contact to ensure acoustic coupling. Between mechanical scanning (MS) and side-looking array (SLA) designs, MS performs better for both imaging performance and system complexity. In vivo imaging in pigs demonstrates promising results, although the effect of peristalsis and resulting coverage needs further investigation and quantification.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126078121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0576
S. Lipman, N. Rouze, M. Palmeri, K. Nightingale
Reflected waves from stiffness boundaries can lead to artifacts in shear wave speed (SWS) reconstructions. 2D directional filters are commonly used with planar imaging systems to reduce in-plane reflected waves; however SWS artifacts arise from both in and out-of imaging plane reflected waves. Herein, we quantify the reduction in image artifacts afforded by the use of volumetric SWS monitoring and 4D directional filters. A Gaussian acoustic radiation force impulse was simulated in a phantom with a Young's modulus (E) of 3 kPa with a 5 mm spherical lesion with E = 6, 12 or 18.75 kPa. 2D, 3D, and 4D directional filters were applied to the displacement profiles to reduce in and out-of-plane reflected wave artifacts. SWS images were reconstructed and RMS error and CNR were calculated for each image to evaluate the image accuracy and quality. Applying 3D directional filters as compared to 2D led to larger improvements in image accuracy and quality than the improvements seen using 4D directional filters over 3D. This improvement in image accuracy is significant because the processing of these data could be performed on displacement data from a traditional 1D linear array with reasonable computational time and resources. Although 4D directional filters can further reduce the impact of large magnitude out-of-plane reflection artifacts in SWS images, computational overhead and transducer costs may outweigh the modest improvements in image quality.
{"title":"Improving the accuracy of shear wave speed reconstructions using 4D directional filters in the presence of reflection artifacts","authors":"S. Lipman, N. Rouze, M. Palmeri, K. Nightingale","doi":"10.1109/ULTSYM.2014.0576","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0576","url":null,"abstract":"Reflected waves from stiffness boundaries can lead to artifacts in shear wave speed (SWS) reconstructions. 2D directional filters are commonly used with planar imaging systems to reduce in-plane reflected waves; however SWS artifacts arise from both in and out-of imaging plane reflected waves. Herein, we quantify the reduction in image artifacts afforded by the use of volumetric SWS monitoring and 4D directional filters. A Gaussian acoustic radiation force impulse was simulated in a phantom with a Young's modulus (E) of 3 kPa with a 5 mm spherical lesion with E = 6, 12 or 18.75 kPa. 2D, 3D, and 4D directional filters were applied to the displacement profiles to reduce in and out-of-plane reflected wave artifacts. SWS images were reconstructed and RMS error and CNR were calculated for each image to evaluate the image accuracy and quality. Applying 3D directional filters as compared to 2D led to larger improvements in image accuracy and quality than the improvements seen using 4D directional filters over 3D. This improvement in image accuracy is significant because the processing of these data could be performed on displacement data from a traditional 1D linear array with reasonable computational time and resources. Although 4D directional filters can further reduce the impact of large magnitude out-of-plane reflection artifacts in SWS images, computational overhead and transducer costs may outweigh the modest improvements in image quality.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125578839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0608
Eduardo A. Gonzalez, N. Sheth, B. Castañeda, J. Dahl, R. Lavarello
Phase aberration is the distortion of the diffraction pattern when a wave propagates in a medium with an inhomogeneous sound speed. In this study, the accuracy of the estimation of backscatter coefficients (BSCs) in the presence of near-field phase aberrations was studied through simulations. Further, the accuracy was also evaluated when using two different phase aberration correction strategies prior to BSC estimation. Simulations were performed using the FIELD II software for pulsed ultrasound field calculation. The simulation utilized a 45 element, 3.5 MHz linear array with 70% bandwidth. The imaging medium consisted of randomly positioned circular scatterers having a diameter of 176 microns. Near field phase aberrators were applied to the transmit and receive signals of the simulation having 50, 75, and 100 ns RMS strength and a 3 mm correlation length. Phase aberrations were estimated using a multi-lag least squares estimation technique. BSCs were estimated using the reference phantom method and radiofrequency data segments with a length of 14 wavelengths and centered around the transducer transmit focus. BSC estimation accuracy was quantified using the average difference in dB between the theoretical and estimated curves within the -10 dB bandwidth of the transducer. The mean BSC estimation errors were -9.31, -12.82 and -15.58 dB in the presence of the 50, 75 and 100 ns aberrators, respectively. The use of aberration correction on receive was inadequate for the BSC accuracy for all three cases. The estimation errors for the 50 ns, 75 ns and 100 ns aberrators were -7.24, -12.66 dB and -14.68 dB, respectively. In contrast, the use of aberration correction on transmit-receive allowed an accurate BSC estimation, with estimation errors lower than 0.7 dB for the first two cases. These results suggest that phase aberration effects may adversely influence the performance of BSC estimation, and that a robust BSC-based tissue characterization may require compensating for the effects of aberration on both transmit and receive beams.
{"title":"Accuracy of backscatter coefficient estimation in aberrating media using different phase aberration correction strategies - A simulation study","authors":"Eduardo A. Gonzalez, N. Sheth, B. Castañeda, J. Dahl, R. Lavarello","doi":"10.1109/ULTSYM.2014.0608","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0608","url":null,"abstract":"Phase aberration is the distortion of the diffraction pattern when a wave propagates in a medium with an inhomogeneous sound speed. In this study, the accuracy of the estimation of backscatter coefficients (BSCs) in the presence of near-field phase aberrations was studied through simulations. Further, the accuracy was also evaluated when using two different phase aberration correction strategies prior to BSC estimation. Simulations were performed using the FIELD II software for pulsed ultrasound field calculation. The simulation utilized a 45 element, 3.5 MHz linear array with 70% bandwidth. The imaging medium consisted of randomly positioned circular scatterers having a diameter of 176 microns. Near field phase aberrators were applied to the transmit and receive signals of the simulation having 50, 75, and 100 ns RMS strength and a 3 mm correlation length. Phase aberrations were estimated using a multi-lag least squares estimation technique. BSCs were estimated using the reference phantom method and radiofrequency data segments with a length of 14 wavelengths and centered around the transducer transmit focus. BSC estimation accuracy was quantified using the average difference in dB between the theoretical and estimated curves within the -10 dB bandwidth of the transducer. The mean BSC estimation errors were -9.31, -12.82 and -15.58 dB in the presence of the 50, 75 and 100 ns aberrators, respectively. The use of aberration correction on receive was inadequate for the BSC accuracy for all three cases. The estimation errors for the 50 ns, 75 ns and 100 ns aberrators were -7.24, -12.66 dB and -14.68 dB, respectively. In contrast, the use of aberration correction on transmit-receive allowed an accurate BSC estimation, with estimation errors lower than 0.7 dB for the first two cases. These results suggest that phase aberration effects may adversely influence the performance of BSC estimation, and that a robust BSC-based tissue characterization may require compensating for the effects of aberration on both transmit and receive beams.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126614422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0268
I. Nenadic, M. Bernal, J. Brum, J. Gennisson, M. Pernot, J. Greenleaf, M. Tanter, M. Urban
The field of shear wave ultrasound elastography has proposed several methods for measuring tissue elasticity by exciting a shear wave in the tissue using acoustic radiation force and measuring the shear wave velocity using pulse-echo ultrasound. In plate-like organs such as the myocardium, the shear and the compressional waves produced by the acoustic radiation force interfere to form Lamb waves. Relating the Lamb wave velocity and tissue elasticity requires the complicated Lamb wave dispersion theory. Two-dimensional (2-D) tracking of the medium deformation allows for removing of the compressional wave contributions. Theory showing the curl of a 2-D particle motion followed by the direct inversion (CDI) in a plate is developed. A finite element model (FEM) of three elastic plates with the shear moduli of 25 kPa, 36 kPa and 49 kPa surrounded by semi-infinite media with the shear modulus of 1 kPa was used to test the theory. The CDI-based elasticity estimates were in excellent agreement with the theoretical values. A mechanical shaker was used to excite plane shear waves in a phantom consisting of a 7 mm 2% agar plate embedded between two semi-infinite 5% gelatin phantoms. Two linear array transducers were used to track the motion perpendicular and parallel to the excitation axis. A 12 × 6 × 4 cm3 agar cube from the same batch as the plate was made to measure the shear wave velocity. The shear wave velocity in the agar plate using the CDI method was in good agreement with the shear wave velocity measured in the cube phantom.
{"title":"Recovering shear wave velocity in boundary sensitive media with two-dimensional motion tracking","authors":"I. Nenadic, M. Bernal, J. Brum, J. Gennisson, M. Pernot, J. Greenleaf, M. Tanter, M. Urban","doi":"10.1109/ULTSYM.2014.0268","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0268","url":null,"abstract":"The field of shear wave ultrasound elastography has proposed several methods for measuring tissue elasticity by exciting a shear wave in the tissue using acoustic radiation force and measuring the shear wave velocity using pulse-echo ultrasound. In plate-like organs such as the myocardium, the shear and the compressional waves produced by the acoustic radiation force interfere to form Lamb waves. Relating the Lamb wave velocity and tissue elasticity requires the complicated Lamb wave dispersion theory. Two-dimensional (2-D) tracking of the medium deformation allows for removing of the compressional wave contributions. Theory showing the curl of a 2-D particle motion followed by the direct inversion (CDI) in a plate is developed. A finite element model (FEM) of three elastic plates with the shear moduli of 25 kPa, 36 kPa and 49 kPa surrounded by semi-infinite media with the shear modulus of 1 kPa was used to test the theory. The CDI-based elasticity estimates were in excellent agreement with the theoretical values. A mechanical shaker was used to excite plane shear waves in a phantom consisting of a 7 mm 2% agar plate embedded between two semi-infinite 5% gelatin phantoms. Two linear array transducers were used to track the motion perpendicular and parallel to the excitation axis. A 12 × 6 × 4 cm3 agar cube from the same batch as the plate was made to measure the shear wave velocity. The shear wave velocity in the agar plate using the CDI method was in good agreement with the shear wave velocity measured in the cube phantom.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126864391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0300
L. Tong, A. Ramalli, G. Fradella, Chengwu Huang, P. Tortoli, Jianwen Luo, J. D’hooge
Colour tissue Doppler imaging (TDI) is a well-established methodology to assess local myocardial motion/deformation. Typically, a frame rate of ~200 Hz can be achieved by imaging a narrow sector (~30°, covering only one cardiac wall) at moderate line density, using a dedicated pulse sequence and multi-line acquisition (MLA). However, a wide angle sector (i.e., wide field-of-view) is required for some clinical applications in order to image the whole left ventricle, which currently implies a drop in the temporal resolution. Recently, multi-line transmit (MLT) beamforming has been shown capable of providing high quality, high frame rate, wide field-of-view B-mode images. Given the capability of MLT, the aim of this study was to test a novel tissue Doppler imaging sequence using the MLT approach to achieve high frame rate tissue Doppler imaging while preserving a wide field-of-view (i.e., 90° sector).
{"title":"Wide-angle tissue Doppler imaging at high frame rate using multi-line transmit beamforming: An in-vivo pilot study","authors":"L. Tong, A. Ramalli, G. Fradella, Chengwu Huang, P. Tortoli, Jianwen Luo, J. D’hooge","doi":"10.1109/ULTSYM.2014.0300","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0300","url":null,"abstract":"Colour tissue Doppler imaging (TDI) is a well-established methodology to assess local myocardial motion/deformation. Typically, a frame rate of ~200 Hz can be achieved by imaging a narrow sector (~30°, covering only one cardiac wall) at moderate line density, using a dedicated pulse sequence and multi-line acquisition (MLA). However, a wide angle sector (i.e., wide field-of-view) is required for some clinical applications in order to image the whole left ventricle, which currently implies a drop in the temporal resolution. Recently, multi-line transmit (MLT) beamforming has been shown capable of providing high quality, high frame rate, wide field-of-view B-mode images. Given the capability of MLT, the aim of this study was to test a novel tissue Doppler imaging sequence using the MLT approach to achieve high frame rate tissue Doppler imaging while preserving a wide field-of-view (i.e., 90° sector).","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115066512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0520
A. Ramalli, P. Tortoli
The increasing interest in 3D ultrasound imaging is pushing the development of 2D probes with a challenging number (N) of active elements. The most popular approach in order to contain N is the sparse array technique. Here the design of the array layout requires complex optimization algorithms, which are typically constrained by a few steering conditions. Ungridded extensions of the sparse array technique offer improved performance by adding a further degree of freedom in the optimization process. In this paper, it is proposed to design the layout of large circular arrays with limited N according to Fermat's spiral seeds with spatial density modulation. This deterministic, aperiodic and balanced positioning procedure aims at guaranteeing uniform performance over a wide range of steering angles. The capabilities of the method is demonstrated by simulation comparing the performance of spiral and dense arrays.
{"title":"256-element density-tapered spiral matrices for ultrasound phased imaging","authors":"A. Ramalli, P. Tortoli","doi":"10.1109/ULTSYM.2014.0520","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0520","url":null,"abstract":"The increasing interest in 3D ultrasound imaging is pushing the development of 2D probes with a challenging number (N) of active elements. The most popular approach in order to contain N is the sparse array technique. Here the design of the array layout requires complex optimization algorithms, which are typically constrained by a few steering conditions. Ungridded extensions of the sparse array technique offer improved performance by adding a further degree of freedom in the optimization process. In this paper, it is proposed to design the layout of large circular arrays with limited N according to Fermat's spiral seeds with spatial density modulation. This deterministic, aperiodic and balanced positioning procedure aims at guaranteeing uniform performance over a wide range of steering angles. The capabilities of the method is demonstrated by simulation comparing the performance of spiral and dense arrays.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"242 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115253091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0348
Alan Conci Kubrusly, A. Braga, J. P. von der Weid, N. Pérez, J. Adamowski, Timoteo Francisco de Oliveira
This paper presents the application of the one-bit time reversal technique to a longitudinal strain sensor. The setup consists of a pair of piezoelectric transducers bonded in the extremities of a strip of aluminum plate. When the plate is subjected to traction, time reversal focalization is performed, the mismatch between the impulse response at initial and strained levels causes loss in the focusing quality. The strain can be evaluated by measuring either the time of flight shift or the amplitude decrease in the focused signal. One-bit time reversal can simplify the electronic device to perform the proposed technique. In this work, the results using one-bit and normal time reversal implementation were compared. Experiments were performed using three different 2-2 piezocomposite transducers pairs at 500, 1000 and 2250 kHz. The longitudinal strain was applied up to 150 μ-strain using a strain gauge as a reference. The time reversal energy efficiency was used as a spectrum figure of merit and obeys the sensitivity behavior. The one-bit time reversal variation provided good focused signal for all experiments and no significant loss in focus quality. Moreover, every configuration showed a higher sensitivity than its normal time reversal version, at least 10% depending on the transducer. The one-bit technique reveals an important enhancement for the method; it holds the natural advantage of being simpler and the benefit of higher sensitivity.
{"title":"Application of one-bit time reversal technique to mechanical strain monitoring in plates","authors":"Alan Conci Kubrusly, A. Braga, J. P. von der Weid, N. Pérez, J. Adamowski, Timoteo Francisco de Oliveira","doi":"10.1109/ULTSYM.2014.0348","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0348","url":null,"abstract":"This paper presents the application of the one-bit time reversal technique to a longitudinal strain sensor. The setup consists of a pair of piezoelectric transducers bonded in the extremities of a strip of aluminum plate. When the plate is subjected to traction, time reversal focalization is performed, the mismatch between the impulse response at initial and strained levels causes loss in the focusing quality. The strain can be evaluated by measuring either the time of flight shift or the amplitude decrease in the focused signal. One-bit time reversal can simplify the electronic device to perform the proposed technique. In this work, the results using one-bit and normal time reversal implementation were compared. Experiments were performed using three different 2-2 piezocomposite transducers pairs at 500, 1000 and 2250 kHz. The longitudinal strain was applied up to 150 μ-strain using a strain gauge as a reference. The time reversal energy efficiency was used as a spectrum figure of merit and obeys the sensitivity behavior. The one-bit time reversal variation provided good focused signal for all experiments and no significant loss in focus quality. Moreover, every configuration showed a higher sensitivity than its normal time reversal version, at least 10% depending on the transducer. The one-bit technique reveals an important enhancement for the method; it holds the natural advantage of being simpler and the benefit of higher sensitivity.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115526260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-10-23DOI: 10.1109/ULTSYM.2014.0191
A. Reinhardt, L. Benaissa, J. David, N. Lamard, V. Kovacova, N. Boudou, E. Defay
Lithium niobate has been extensively used in the Surface Acoustic Wave (SAW) industry for its excellent piezoelectric properties. In the last twelve years, the interest has been raised towards making this material available in the thin film form for SAW or Bulk Acoustic Wave (BAW) applications, and even for Lamb wave devices. This paper reviews both deposition or thin film transfer techniques to obtain lithium niobate thin films. It also gives a brief overview of the applications of these thin films. Finally, we open new perspectives for this technology with the emerging field of tunable acoustic filters, which need extremely large piezoelectric properties to demonstrate satisfying performance.
{"title":"Acoustic filters based on thin single crystal LiNbO3 films: Status and prospects","authors":"A. Reinhardt, L. Benaissa, J. David, N. Lamard, V. Kovacova, N. Boudou, E. Defay","doi":"10.1109/ULTSYM.2014.0191","DOIUrl":"https://doi.org/10.1109/ULTSYM.2014.0191","url":null,"abstract":"Lithium niobate has been extensively used in the Surface Acoustic Wave (SAW) industry for its excellent piezoelectric properties. In the last twelve years, the interest has been raised towards making this material available in the thin film form for SAW or Bulk Acoustic Wave (BAW) applications, and even for Lamb wave devices. This paper reviews both deposition or thin film transfer techniques to obtain lithium niobate thin films. It also gives a brief overview of the applications of these thin films. Finally, we open new perspectives for this technology with the emerging field of tunable acoustic filters, which need extremely large piezoelectric properties to demonstrate satisfying performance.","PeriodicalId":153901,"journal":{"name":"2014 IEEE International Ultrasonics Symposium","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122634617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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