Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663301
D. Simpson, P. Burns
A novel technique for the selective detection of ultrasound contrast agents, called pulse inversion Doppler, has been developed. In this technique, a conventional Doppler pulse sequence is modified by inverting every second transmit pulse. Either conventional or harmonic Doppler processing is then performed on the received echoes. In the resulting Doppler spectra, Doppler shifts from linear and nonlinear scattering are separated into two distinct regions which can be analyzed separately or combined to estimate the ratio of nonlinear to linear scattering from a region of tissue. The maximum Doppler shift which can be detected is 1/2 the normal Nyquist limit. In vitro measurements comparing flowing agent and cellulose particles suggest that pulse inversion Doppler can provide 3 to 10 dB more agent to tissue contrast than harmonic imaging with similar pulses. Similar measurements suggest that broadband pulse inversion Doppler can provide up to 16 dB more contrast than broadband conventional Doppler.
{"title":"Pulse inversion Doppler: a new method for detecting nonlinear echoes from microbubble contrast agents","authors":"D. Simpson, P. Burns","doi":"10.1109/ULTSYM.1997.663301","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663301","url":null,"abstract":"A novel technique for the selective detection of ultrasound contrast agents, called pulse inversion Doppler, has been developed. In this technique, a conventional Doppler pulse sequence is modified by inverting every second transmit pulse. Either conventional or harmonic Doppler processing is then performed on the received echoes. In the resulting Doppler spectra, Doppler shifts from linear and nonlinear scattering are separated into two distinct regions which can be analyzed separately or combined to estimate the ratio of nonlinear to linear scattering from a region of tissue. The maximum Doppler shift which can be detected is 1/2 the normal Nyquist limit. In vitro measurements comparing flowing agent and cellulose particles suggest that pulse inversion Doppler can provide 3 to 10 dB more agent to tissue contrast than harmonic imaging with similar pulses. Similar measurements suggest that broadband pulse inversion Doppler can provide up to 16 dB more contrast than broadband conventional Doppler.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"18 9 1","pages":"1597-1600 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82896728","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661725
N. Abboud, J. Mould, G. Wojcik, D. Vaughan, D. Powell, V. Murray, C. Maclean
Thermal management is an important consideration in ultrasound transducer design. It arises in satisfying regulatory and safety requirements in diagnostic and therapeutic ultrasound, as well as in sustaining performance in high power applications such as underwater sonar. A finite element modeling approach was developed to aid in the analysis of this coupled electro-mechanical-thermal problem. The finite element model tracks the damping losses in the electromechanical portion of the problem and converts the lost energy into a thermal dose which constitutes the "input" to the thermal portion of the problem. The resultant temperature spatial and temporal distribution is then solved for. This modeling approach was used to study several 1-3 piezocomposite high power transducers for which experimental data was available. Previous experimental evaluation has demonstrated that these devices can suffer from a degradation in performance due to significant temperature rises at power levels of approximately 2 W/cm/sup 2/ for continuous operation, whereas they can operate efficiently at power levels greater than 20 W/cm/sup 2/ when the duty cycle is reduced below 10%. A detailed thermal analysis of these transducers with respect to efficiency of the thermal dissipation within them is required with a view to understanding and consequently improving the high drive performance of these devices. The goal of this preliminary study is to evaluate the modeling approach and identify key parameters to which the solution is sensitive. Parameters so identified, be they material constants or modeling approaches, will be subject to more complete characterization in follow-up studies aimed at quantitative validation of computational modeling of thermal management in ultrasonic applications.
{"title":"Thermal generation, diffusion and dissipation in 1-3 piezocomposite sonar transducers: finite element analysis and experimental measurements","authors":"N. Abboud, J. Mould, G. Wojcik, D. Vaughan, D. Powell, V. Murray, C. Maclean","doi":"10.1109/ULTSYM.1997.661725","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661725","url":null,"abstract":"Thermal management is an important consideration in ultrasound transducer design. It arises in satisfying regulatory and safety requirements in diagnostic and therapeutic ultrasound, as well as in sustaining performance in high power applications such as underwater sonar. A finite element modeling approach was developed to aid in the analysis of this coupled electro-mechanical-thermal problem. The finite element model tracks the damping losses in the electromechanical portion of the problem and converts the lost energy into a thermal dose which constitutes the \"input\" to the thermal portion of the problem. The resultant temperature spatial and temporal distribution is then solved for. This modeling approach was used to study several 1-3 piezocomposite high power transducers for which experimental data was available. Previous experimental evaluation has demonstrated that these devices can suffer from a degradation in performance due to significant temperature rises at power levels of approximately 2 W/cm/sup 2/ for continuous operation, whereas they can operate efficiently at power levels greater than 20 W/cm/sup 2/ when the duty cycle is reduced below 10%. A detailed thermal analysis of these transducers with respect to efficiency of the thermal dissipation within them is required with a view to understanding and consequently improving the high drive performance of these devices. The goal of this preliminary study is to evaluate the modeling approach and identify key parameters to which the solution is sensitive. Parameters so identified, be they material constants or modeling approaches, will be subject to more complete characterization in follow-up studies aimed at quantitative validation of computational modeling of thermal management in ultrasonic applications.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"89 1","pages":"895-900 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80250719","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.662994
W. Liu, P.M. Smith
Electrode interactions are a major cause of in-band ripples in SAW filters. In the past, the effect of these interactions has been modeled on devices with periodic electrodes either with the aid of Coupling of Modes (COM) theory, or by adopting the quasi-static Green's function method. In this paper, we extend the quasi-static Green's function to include electro-acoustic regeneration in transducers with non-periodic electrodes. The simulation of a dispersive delay line is given as an example.
{"title":"An efficient method of including electrode interactions in the Green's function model for SAW interdigital transducers","authors":"W. Liu, P.M. Smith","doi":"10.1109/ULTSYM.1997.662994","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.662994","url":null,"abstract":"Electrode interactions are a major cause of in-band ripples in SAW filters. In the past, the effect of these interactions has been modeled on devices with periodic electrodes either with the aid of Coupling of Modes (COM) theory, or by adopting the quasi-static Green's function method. In this paper, we extend the quasi-static Green's function to include electro-acoustic regeneration in transducers with non-periodic electrodes. The simulation of a dispersive delay line is given as an example.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"16 1","pages":"131-134 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82774859","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661751
L. Zou, M. Sayer, C. Jen
Sol-gel fabricated thick film broadband piezoelectric ultrasonic transducers (UTs) operating at a frequency below 10 MHz are presented. The UTs are formed using thick PZT and LiNbO/sub 3/ films which are ceramic-ceramic composites formed by dispersing PZT and LiNbO/sub 3/ particles in a PZT and LiNbO/sub 3/ sol-gel solution, respectively. Films are directly deposited on stainless steel substrates. Excellent broadband signals have been experimentally obtained with piezoelectric PZT and LiNbO/sub 3/ films with 1 cm diameter and a thickness between 40-50 /spl mu/m.
{"title":"Sol-gel fabricated thick piezoelectric ultrasonic transducers for potential applications in industrial material processes","authors":"L. Zou, M. Sayer, C. Jen","doi":"10.1109/ULTSYM.1997.661751","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661751","url":null,"abstract":"Sol-gel fabricated thick film broadband piezoelectric ultrasonic transducers (UTs) operating at a frequency below 10 MHz are presented. The UTs are formed using thick PZT and LiNbO/sub 3/ films which are ceramic-ceramic composites formed by dispersing PZT and LiNbO/sub 3/ particles in a PZT and LiNbO/sub 3/ sol-gel solution, respectively. Films are directly deposited on stainless steel substrates. Excellent broadband signals have been experimentally obtained with piezoelectric PZT and LiNbO/sub 3/ films with 1 cm diameter and a thickness between 40-50 /spl mu/m.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"19 1","pages":"1007-1012 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88775552","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661852
J. Gorce, D. Friboulet, J. D’hooge, B. Bijnens, I. Magnin
The local spectral estimation from radio-frequency (RF) signals in medical echographic ultrasound images is not a trivial task due to the noisy nature of the data resulting from a stochastic and nonstationary process, Significant improvements may be obtained by proposing a spatial regularization scheme, smoothing the local spectral estimates while preserving the discontinuities. Based on AR models, the authors propose a 2D regularization scheme in a Bayesian framework. The a-priori knowledge is expressed by means of Markovian Random Fields (MRF) defined on the reflection coefficients. The use of nonquadratic functions allows to preserve discontinuities. First the authors applied their method on simulated data containing spatial discontinuities of spectral characteristics, which showed the efficiency of the regularization technique. Then the technique was used on cardiac RF data. This shows the improvements as well for Integrated Backscatter (IBS) images as for Mean Central Frequency (MCF) Images or whole spectral estimation.
{"title":"Regularized autoregressive models for a spectral estimation scheme dedicated to medical ultrasonic radio-frequency images","authors":"J. Gorce, D. Friboulet, J. D’hooge, B. Bijnens, I. Magnin","doi":"10.1109/ULTSYM.1997.661852","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661852","url":null,"abstract":"The local spectral estimation from radio-frequency (RF) signals in medical echographic ultrasound images is not a trivial task due to the noisy nature of the data resulting from a stochastic and nonstationary process, Significant improvements may be obtained by proposing a spatial regularization scheme, smoothing the local spectral estimates while preserving the discontinuities. Based on AR models, the authors propose a 2D regularization scheme in a Bayesian framework. The a-priori knowledge is expressed by means of Markovian Random Fields (MRF) defined on the reflection coefficients. The use of nonquadratic functions allows to preserve discontinuities. First the authors applied their method on simulated data containing spatial discontinuities of spectral characteristics, which showed the efficiency of the regularization technique. Then the technique was used on cardiac RF data. This shows the improvements as well for Integrated Backscatter (IBS) images as for Mean Central Frequency (MCF) Images or whole spectral estimation.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"14 1","pages":"1461-1464 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89950670","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663033
S.E. Carter, D. Malocha
This paper introduces a new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudo noise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to have improved compression ratio (CR) and peak sidelobe level (PSL) versus a PN code with identical code length and chip length. It also will be shown to have a similar CR and PSL compared to a CW chirp with identical pulse length and frequency deviation. The code signal is implemented on surface acoustic wave (SAW) devices which will be used as the code generator at the transmitter and the correlator at the receiver. Experimental data is presented and compared to the predicted results.
{"title":"SAW device implementation of a new weighted stepped chirp code signal for direct sequence spread spectrum communications systems","authors":"S.E. Carter, D. Malocha","doi":"10.1109/ULTSYM.1997.663033","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663033","url":null,"abstract":"This paper introduces a new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudo noise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to have improved compression ratio (CR) and peak sidelobe level (PSL) versus a PN code with identical code length and chip length. It also will be shown to have a similar CR and PSL compared to a CW chirp with identical pulse length and frequency deviation. The code signal is implemented on surface acoustic wave (SAW) devices which will be used as the code generator at the transmitter and the correlator at the receiver. Experimental data is presented and compared to the predicted results.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"1 1","pages":"329-333 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90226311","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.662986
Yuxing Zhang, J. Gong, Xianwen Zhou, Yulan Wei, J. Cheeke
In this paper, two high-resolution spectrometer systems based on SAW Chirp-Z-Transform are reported. To achieve high frequency resolutions of 15 kHz (for unweighted compressor) and 20 kHz (for weighted compressor), two SAW RAC, with 68 /spl mu/s dispersion duration each, are cascaded as an expander to offer a long-duration chirp signal and another RAC also with 68 /spl mu/s dispersion is used as the compressor. Both systems are developed in the form of independent modules, and can be used as general-purpose spectrometer subsystems.
{"title":"High-resolution spectrometer systems based on SAW chirp filters","authors":"Yuxing Zhang, J. Gong, Xianwen Zhou, Yulan Wei, J. Cheeke","doi":"10.1109/ULTSYM.1997.662986","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.662986","url":null,"abstract":"In this paper, two high-resolution spectrometer systems based on SAW Chirp-Z-Transform are reported. To achieve high frequency resolutions of 15 kHz (for unweighted compressor) and 20 kHz (for weighted compressor), two SAW RAC, with 68 /spl mu/s dispersion duration each, are cascaded as an expander to offer a long-duration chirp signal and another RAC also with 68 /spl mu/s dispersion is used as the compressor. Both systems are developed in the form of independent modules, and can be used as general-purpose spectrometer subsystems.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"47 1","pages":"89-92 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90354282","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661753
K. Imano, H. Inoue
The cycloid function voltage having no resonant component is applied to the piezo-ceramic planar and concave circular transducers to generate the monopole ultrasonic pulse. On-axis pressure characteristics of two kinds of transducer are observed using monopole ultrasonic pulse. As the experimental results, 1) the sound field of monopole ultrasonic pulse is consisted of direct wave and edge wave, and these are separated in time near the transducer, 2) the monopole ultrasonic pulse from a planar transducer becomes bipolar pulse in the large distance from the transducer and 3) in case of the concave transducer, the monopole ultrasonic pulse is gradually changed to the bipolar pulse around the focus, are clearly observed. These experimental results can be explained by the interference between direct wave and edge wave using monopole ultrasonic pulse. A possibilities of the diffraction effect which dominated at the focus of concave transducer is also suggested.
{"title":"A simple method for generating the monopole ultrasonic pulse and its sound field","authors":"K. Imano, H. Inoue","doi":"10.1109/ULTSYM.1997.661753","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661753","url":null,"abstract":"The cycloid function voltage having no resonant component is applied to the piezo-ceramic planar and concave circular transducers to generate the monopole ultrasonic pulse. On-axis pressure characteristics of two kinds of transducer are observed using monopole ultrasonic pulse. As the experimental results, 1) the sound field of monopole ultrasonic pulse is consisted of direct wave and edge wave, and these are separated in time near the transducer, 2) the monopole ultrasonic pulse from a planar transducer becomes bipolar pulse in the large distance from the transducer and 3) in case of the concave transducer, the monopole ultrasonic pulse is gradually changed to the bipolar pulse around the focus, are clearly observed. These experimental results can be explained by the interference between direct wave and edge wave using monopole ultrasonic pulse. A possibilities of the diffraction effect which dominated at the focus of concave transducer is also suggested.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"12 1","pages":"1017-1019 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84632698","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663295
S. Krishnan, J. D. Hamilton, Matthew O'Donnell
Harmonic imaging can improve contrast between contrast agents and tissue when imaging microvasculature. However, the factor limiting contrast enhancement is harmonic signals generated by the medium as the ultrasound signal propagates through it. Here, the authors have developed a method known as the Harmonic Cancellation System (HCS) to suppress this propagating second harmonic and improve contrast between contrast agents and the surrounding tissue for harmonic imaging. Simulations and experiments have shown that the level of second harmonic signals can be reduced by about 30 dB using HCS.
{"title":"Suppression of propagating second harmonic in non-linear imaging","authors":"S. Krishnan, J. D. Hamilton, Matthew O'Donnell","doi":"10.1109/ULTSYM.1997.663295","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663295","url":null,"abstract":"Harmonic imaging can improve contrast between contrast agents and tissue when imaging microvasculature. However, the factor limiting contrast enhancement is harmonic signals generated by the medium as the ultrasound signal propagates through it. Here, the authors have developed a method known as the Harmonic Cancellation System (HCS) to suppress this propagating second harmonic and improve contrast between contrast agents and the surrounding tissue for harmonic imaging. Simulations and experiments have shown that the level of second harmonic signals can be reduced by about 30 dB using HCS.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"62 1","pages":"1567-1570 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83659112","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661783
E. Konofagou, S. Alam, J. Ophir, T. Krouskop
Two methods are discussed to increase the dynamic range and enhance the signal-to-noise ratio in elastography (SNR/sub e/). One method uses variable applied strains to expand the elastographic dynamic range by selecting the strain estimates with the highest SNR/sub e/ out of a multitude of strain estimates. The second one is a completely new estimator that estimates the strain by an iterative temporal stretching algorithm of the windowed postcompression RF echo signal. The authors examine these methods using 2D finite element simulations and resulting experimental strain filters. Finally, the combination of these two methods is shown to produce an elastogram with higher dynamic range as well as SNR/sub e/.
{"title":"Methods for dynamic range expansion and enhancement of the signal-to-noise ratio in elastography","authors":"E. Konofagou, S. Alam, J. Ophir, T. Krouskop","doi":"10.1109/ULTSYM.1997.661783","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661783","url":null,"abstract":"Two methods are discussed to increase the dynamic range and enhance the signal-to-noise ratio in elastography (SNR/sub e/). One method uses variable applied strains to expand the elastographic dynamic range by selecting the strain estimates with the highest SNR/sub e/ out of a multitude of strain estimates. The second one is a completely new estimator that estimates the strain by an iterative temporal stretching algorithm of the windowed postcompression RF echo signal. The authors examine these methods using 2D finite element simulations and resulting experimental strain filters. Finally, the combination of these two methods is shown to produce an elastogram with higher dynamic range as well as SNR/sub e/.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"65 1","pages":"1157-1160 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82545031","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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