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IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

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https://www.readbyqxmd.com/read/28333626/temperature-dependence-of-domain-contributions-as-a-function-of-ageing-in-soft-and-hard-lead-zirconate-titanate-piezoelectric-ceramics
#1
Sayyed A Qaisar, Timothy P Comyn, Andrew J Bell
The stress and temperature dependence of three different PZT ceramics have been measured at 48 hours and 1 month after poling. The data were fitted to a modified Rayleigh law in which a negative quadratic stress term accounts for a saturation of the domain wall contributions at higher stress. The relative changes to the fitting parameters can be explained by the materials possessing differences in the concentration of orientable defect dipoles, but with similar distributions of relaxation time constants.
March 22, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28333625/real-time-nonlocal-means-based-despeckling
#2
Lars H Breivik, Sten Roar Snare, Erik N Steen, Anne H Solberg
In this paper we propose a multiscale nonlocal means based despeckling method for medical ultrasound. The multiscale approach leads to large computational savings and improves despeckling results over single scale iterative approaches. We present two variants of the method. The first, denoted multiscale nonlocal means, yields uniform robust filtering of speckle both in structured and homogeneous regions. The second, denoted unnormalized multiscale nonlocal means, is more conservative in regions of structure assuring minimal disruption of salient image details...
March 22, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28333624/a-fast-and-robust-beamspace-adaptive-beamformer-for-medical-ultrasound-imaging
#3
Ali Mohades Deylami, Babak Mohammadzadeh Asl
Minimum variance beamformer (MVB) increases the resolution and contrast of medical ultrasound imaging compared to non-adaptive beamformers. These advantages come at the expense of high computational complexity that prevents this adaptive beamformer to be applied in a real-time imaging system. A new beamspace based on discrete cosine transform (DCT) is proposed in which the medical ultrasound signals can be represented with less dimensions compared to the standard beamspace. This is because of symmetric beampattern of the beams in the proposed beamspace compared to the asymmetric ones in the standard beamspace...
March 21, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28328505/blocked-elements-in-1-d-and-2-d-arrays-part-ii-compensation-methods-as-applied-to-large-coherent-apertures
#4
Marko Jakovljevic, Nick Bottenus, Lily Kuo, Shalki Kumar, Jeremy J Dahl, Gregg E Trahey
In Part I of the paper, we detected elements blocked by ribs during simulated and in vivo transcostal liver scans, and we turned those elements off to compensate for the loss in visibility of liver vasculature. Here, we apply blocked-element detection and adaptive compensation to large synthetic aperture data collected through rib samples ex vivo, in order to reduce near-field clutter and to recover lateral resolution. To construct large synthetic transmit and receive apertures, we collected the individual channel signals from a fully-sampled matrix array at multiple and know array locations across the tissue samples...
March 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28328504/blocked-elements-in-1-d-and-2-d-arrays-part-i-detection-and-basic-compensation-on-simulated-and-i-in-vivo-i-targets
#5
Marko Jakovljevic, Gianmarco Pinton, Jeremy J Dahl, Gregg Trahey
During a transcostal ultrasound scan, ribs and other highly attenuating and/or reflective tissue structures can block parts of the array. Blocked elements tend to limit the acoustic window and impede visualization of structures of interest. Here, we demonstrate a method to detect blocked elements and we measure the loss of image quality they introduce in simulation and in vivo. We utilize a fullwave simulation tool and a clinical ultrasound scanner to obtain element signals from fullysampled matrix arrays during simulated and in vivo transcostal liver scans, respectively...
March 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28320660/experimental-validation-of-a-fast-forward-model-for-guided-wave-tomography-of-pipe-elbows
#6
Alexander J Brath, Francesco Simonetti, Peter B Nagy, Geir Instanes
Ultrasonic guided wave tomography (GWT) methods for the detection of corrosion and erosion damage in straight pipe sections are now well advanced. However, successful application of GWT to pipe bends has not yet been demonstrated due to the computational burden associated with the complex forward model required to simulate guided wave propagation through the bend. In a previous paper [Brath et al., IEEE Trans. Ultrason. Ferroelectr. Freq. Contr., vol. 61, pp. 815-829, 2014] we have shown that the speed of the forward model can be increased by replacing the three-dimensional pipe bend with a two-dimensional rectangular domain in which guided wave propagation is formulated based on an artificially inhomogeneous and elliptically anisotropic (INELAN) acoustic model...
March 15, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28320659/guided-wave-tomography-of-pipe-bends
#7
Alexander J Brath, Francesco Simonetti, Peter Nagy, Geir Instanes
Detection and monitoring of corrosion and erosion damage in pipe bends are open challenges due to the curvature of the elbow, the complex morphology of these defects, and their unpredictable location. Combining model-based inversion with guided ultrasonic waves propagating along the elbow and inside its walls, offers the possibility of mapping wall-thickness losses over the entire bend and from a few permanently installed transducers under the realm of guided wave tomography (GWT). This paper provides the experimental demonstration of GWT of pipe bends based on a novel curved ray tomography algorithm and an optimal transducer configuration consisting of two ring arrays mounted at the ends of the elbow and a line of transducers fixed to the outer side of the elbow (extrados)...
March 15, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28320655/a-study-on-the-effects-of-release-area-on-the-quality-factor-of-contour-mode-resonators-by-laser-doppler-vibrometry
#8
Brian Gibson, Kamala Qalandar, Cristian Cassella, Gianluca Piazza, Kimberly L Turner
Through the use of a laser Doppler vibrometer it is shown that a 31% variation in quality factor can occur due to the effect of undercutting of the device layers outside of the anchors of a 220MHz aluminum nitride contour mode resonator. This undercutting is a result of the isotropic etch process used to release the device from the substrate. This paper shows that the variation in Q is a function of the release distance, L, between the active region of the resonator and the edge of this released region. This study also determined a design modification that eliminated this issue and achieved a Q of 3048 that is independent of L...
March 15, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28320658/compressed-sensing-based-synthetic-transmit-aperture-imaging-validation-in-a-convex-array-configuration
#9
Jing Liu, Qiong He, Jianwen Luo
According to the linear acoustic theory, the channel data of a plane wave emitted by a linear array is a linear combination of the full dataset of synthetic transmit aperture (STA). Combining this relationship with compressed sensing (CS), a novel CS based ultrasound beamforming strategy, named compressed sensing based synthetic transmit aperture (CS-STA), was previously proposed to increase the frame rate of ultrasound imaging without sacrificing the image quality for a linear array. In this paper, assuming linear transfer function of pulse-echo ultrasound system, we derived and applied the theory of CS-STA for a slightly curved array and validated CS-STA in a convex array configuration...
March 14, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28320657/regularized-dual-averaging-image-reconstruction-for-full-wave-ultrasound-computed-tomography
#10
Thomas Matthews, Kun Wang, Cuiping Li, Neb Duric, Mark Anastasio
Ultrasound computed tomography (USCT) holds great promise for breast cancer screening. Waveform inversionbased image reconstruction methods account for higher-order diffraction effects and can produce high-resolution USCT images, but are computationally demanding. Recently, a source encoding technique was combined with stochastic gradient descent to greatly reduce image reconstruction times. However, this method bundles the stochastic data fidelity term with the deterministic regularization term. This limitation can be overcome by replacing stochastic gradient descent (SGD) with a structured optimization method, such as the regularized dual averaging (RDA) method, that exploits knowledge of the composition of the cost function...
March 14, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28320656/targeting-effects-on-the-volume-of-the-focused-ultrasound-induced-blood-brain-barrier-opening-in-non-human-primates-in-vivo
#11
Maria Eleni Karakatsani, Gesthimani Samiotaki, Matthew Downs, Vincent Ferrera, Elisa Konofagou
Drug delivery to subcortical regions is susceptible to the blood-brain barrier (BBB) impeding the molecular exchange between the blood stream and the brain parenchyma. Focused ultrasound coupled with the administration of microbubbles has been proven to open the BBB locally, transiently and non-invasively both in rodents and in Non-Human-Primates (NHPs). The development of this disruption technique independent of MRI monitoring is of primordial importance yet restrained to the targeting optimization. The current paper establishes the linear relationship of the incidence angle with the volume of BBB opening (VBBB) and the Peak Negative Pressure (PNP) when sonicating the Caudate Nucleus and the Putamen region of five non-human-primates...
March 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28287967/vibrational-responses-of-bound-and-non-bound-targeted-lipid-coated-single-microbubbles
#12
Tom van Rooij, Ines Beekers, Kirby R Lattwein, Ton van der Steen, Nico de Jong, Klazina Kooiman
One of the main challenges for ultrasound molecular imaging is acoustically distinguishing non-bound microbubbles from those bound to their molecular target. In this in vitro study, we compared two types of in-house produced targeted lipidcoated microbubbles, either consisting of DPPC or DSPC lipid as the main lipid, using the Brandaris 128 ultra-high-speed camera to determine vibrational response differences between bound and non-bound biotinylated microbubbles. In contrast to previous studies that studied vibrational differences upon binding, we used a covalently bound model biomarker (i...
March 7, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28252394/development-of-an-acoustic-levitation-linear-transportation-system-based-on-a-ring-type-structure
#13
Gilles Thomas, Marco Aurelio Andrade, Julio Adamowski, Emilio Silva
A linear acoustic levitation transportation system based on a ring-type vibrator is presented. The system is composed by two 21 kHz Langevin transducers connected to a ring-shaped structure formed by two semicircular sections and two flat plates. In this system, a flexural standing wave is generated along the ring structure, producing an acoustic standing wave between the vibrating ring and a plane reflector located at a distance of approximately a half wavelength from the ring. The acoustic standing wave in air has a series of pressure nodes, where small particles can be levitated and transported...
February 23, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28212081/a-comparative-analysis-of-cmut-receiving-architectures-for-design-optimization-of-integrated-transceiver-front-ends
#14
Marco Sautto, Alessandro Stuart Savoia, Fabio Quaglia, Giosue Caliano, Andrea Mazzanti
A formal comparison between fundamental RX amplifier configurations for Capacitive Micromachined Ultrasonic Transducers (CMUT) is proposed in this paper. The impact on both RX and the pulse-echo frequency response and on the output SNR are thoroughly analysed and discussed. It is shown that the resistive-feedback amplifier yields a band-pass RX frequency response, while both open-loop voltage and capacitivefeedback amplifiers exhibit a low-pass frequency response. For a given power dissipation, it is formally proved that a capacitivefeedback amplifier provides a remarkable SNR improvement against the commonly adopted resistive feedback stage, achieved at the expense of a reduced pulse-echo center frequency, making its use convenient in low and mid-frequency ultrasound imaging applications...
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28207393/optimization-of-the-close-to-carrier-phase-noise-in-a-cmos-mems-oscillator-using-a-phase-tunable-sustaining-amplifier
#15
Guillermo Sobreviela, Martin Riverola, Francesc Canals, Arantxa Del Monte, Nuria Beumala
In this paper, the phase noise of a 24-MHz CMOSMEMS oscillator with zero-level vacuum package is studied. We characterize and analyze the nonlinear regime of each one of the modules that compose the oscillator (CMOS sustaining-amplifier and MEMS resonator). As we show, the presented resonator exhibits a high nonlinear behavior. Such fact is exploited as a mechanism to stabilize the oscillation amplitude, allowing to maintain the sustaining-amplifier working in the linear regime. Consequently, the nonlinear resonator becomes the main closeto- carrier phase noise source...
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28207391/confidence-estimates-in-simulation-of-phase-noise-or-spectral-density
#16
Neil Ashby
In this paper we apply the method of discrete simulation of power law noise, developed in [1],[3],[4], to the problem of simulating phase noise for a combination of power law noises. We derive analytic expressions for the probability of observing a value of phase noise L(f) or of any of the onesided spectral densities S(f); Sy(f), or Sx(f), for arbitrary superpositions of power law noise.
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28207392/temperature-compensation-of-silicon-lam%C3%A3-resonators-using-etch-holes-theory-and-design-methodology
#17
Luca Luschi, Giuseppe Iannaccone, Francesco Pieri
We present a new approach to the temperature compensation of MEMS Lamé resonators, based on the combined effect of the doping concentration and of the geometry of etch holes on the equivalent temperature coefficients of silicon. To this purpose, we develop and validate an analytical model which describes the effect of etch holes on the temperature stability of Lamé resonators through comparison with experiments available in the literature and FEM simulations. We show that two interesting regions of the design space for Lamé resonators exist, where a cancellation of the first-order temperature coefficient of the resonance frequency is possible: [100]-oriented silicon with n-doping of 2...
February 9, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28186887/accelerated-singular-value-based-ultrasound-blood-flow-clutter-filtering-with-randomized-singular-value-decomposition-rsvd-and-randomized-spatial-downsampling
#18
Pengfei Song, Joshua Trzasko, Armando Manduca, Bo Qiang, Ramanathan Kadirvel, David Kallmes, Shigao Chen
Singular value decomposition (SVD)-based ultrasound blood flow clutter filters have recently demonstrated substantial improvement in clutter rejection for ultrafast plane wave microvessel imaging, and have become the commonly used clutter filtering method for many novel ultrafast imaging applications such as functional ultrasound and super-resolution imaging. At present, however, the computational burden of SVD remains as a major hurdle for practical implementation and clinical translation of this method. To address this challenge, in the study we present two blood flow clutter filtering methods based on randomized singular value decomposition (rSVD) and randomized spatial downsampling to accelerate SVD clutter filtering with minimal compromise to the clutter filter performance...
February 7, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28166493/a-gpu-accelerated-3d-coupled-sub-sample-estimation-algorithm-for-volumetric-breast-strain-elastography
#19
Bo Peng, Yuqi Wang, Timothy J Hall, Jingfeng Jiang
Our primary objective of this work was to extend a previously published 2D coupled sub-sample tracking algorithm for 3D speckle tracking in the framework of ultrasound breast strain elastography. In order to overcome heavy computational cost, we investigated the use of a graphic processing unit (GPU) to accelerate the 3D coupled sub-sample speckle tracking method. The performance of the proposed GPU implementation was tested using a tissue-mimicking (TM) phantom and in vivo breast ultrasound data. The performance of this 3D sub-sample tracking algorithm was compared with the conventional 3D quadratic subsample estimation algorithm...
January 31, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28166492/coded-excitation-for-low-snr-pulse-echo-systems
#20
Julio Isla, Frederic Cegla
Pulse compression has been used for decades in radar, sonar, medical and industrial ultrasound. It consists in transmitting a modulated and/or coded excitation, which is then cross-correlated with the received signal such that received echoes are time-compressed, thereby increasing their intensity and hence the system resolution and signal-to-noise ratio (SNR). A central problem in pulse-echo systems is that, while longer coded excitations yield higher SNRs, the length of the coded excitation or sequence is limited by the distance between the closest reflector and the transmitter/receiver...
January 30, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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