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Beamforming noise

Jinxin Zhao, Yuanyuan Wang, Jinhua Yu, Wei Guo, Shun Zhang, Saeid Aliabadi
The short-lag spatial coherence (SLSC) imaging has been demonstrated to be advantageous over the traditional B-mode ultrasound imaging. With focused scanning beams, the SLSC imaging has an excellent performance in clutter reduction and lesion detection, especially in the low signal-to-noise ratio (SNR) scenarios. The synthetic aperture (SA) imaging is an appropriate mode for the SLSC imaging as the dynamic transmit focusing could keep a good focusing quality at any depth. However, the SLSC image may still suffer a bad resolution performance when a low lag value is used in the coherence summation to ensure the contrast enhancement...
January 1, 2017: Ultrasonic Imaging
Perry Naughton, Philippe Roux, Riley Yeakle, Curt Schurgers, Ryan Kastner, Jules S Jaffe, Paul L D Roberts
This paper presents a demonstration of ambient acoustic noise processing on a set of free floating oceanic receivers whose relative positions vary with time. It is shown that it is possible to retrieve information that is relevant to the travel time between the receivers. With thousands of short time cross-correlations (10 s) of varying distance, it is shown that on average, the decrease in amplitude of the noise correlation function with increased separation follows a power law. This suggests that there may be amplitude information that is embedded in the noise correlation function...
December 2016: Journal of the Acoustical Society of America
Youngmin Choo, Woojae Seong
Noises by incipient propeller tip vortex cavitation (TVC) are generally generated at regions near the propeller tip. Localization of these sparse noises is performed using compressive sensing (CS) with measurement data from cavitation tunnel experiments. Since initial TVC sound radiates in all directions as a monopole source, a sensing matrix for CS is formulated by adopting spherical beamforming. CS localization is examined with known source acoustic measurements, where the CS estimated source position coincides with the known source position...
December 2016: Journal of the Acoustical Society of America
Giulia Matrone, Alessandro Stuart Savoia, Giosuè Caliano, Giovanni Magenes
The Synthetic Aperture Focusing (SAF) technique makes it possible to achieve a higher and more uniform quality of ultrasound images throughout depth, as if both transmit and receive dynamic focusing were applied. In this work we combine a particular implementation of SAF, called Synthetic Transmit Aperture (STA) technique, in which a single element in turn transmits and all the array elements receive the ultrasound wave, with the Filtered-Delay Multiply and Sum (F-DMAS) non-linear beamforming algorithm that we presented in a previous paper...
March 2017: Ultrasonics
Mahsa Sotoodeh Ziksari, Babak Mohammadzadeh Asl
In recent years, applying adaptive beamforming to ultrasound imaging improves image quality in terms of resolution and contrast. One of the best adaptive beamformers in this field is the minimum variance (MV) beamformer which presents better resolution and edge definition compared to the traditional delay-and-sum (DAS) beamformer. However, in real situations, sound-velocity inhomogeneities cause phase aberration which leads to ambiguity in targets' location and degradation in resolution. This effect is a fundamental obstacle to utilize advantages of MV beamformer, although, in aberrating medium MV beamformer results in better performance compared to DAS...
March 2017: Ultrasonics
Diange Yang, Junjie Wen, Feng Miao, Ziteng Wang, Xiaoan Gu, Xiaomin Lian
Identification and measurement of moving sound sources are the bases for vehicle noise control. Acoustic holography has been applied in successfully identifying the moving sound source since the 1990s. However, due to the high demand for the accuracy of holographic data, currently the maximum velocity achieved by acoustic holography is just above 100 km/h. The objective of this study was to establish a method based on the complete Morse acoustic model to restore the measured signal in high-speed situations, and to propose a far-field acoustic holography method applicable for high-speed moving sound sources...
September 2016: Journal of the Acoustical Society of America
Lanfranco Muzi, Martin Siderius, Peter L Nielsen
Accurate modeling of acoustic propagation in the ocean waveguide is important to SONAR-performance prediction. Particularly in shallow waters, a crucial contribution to the total transmission loss is the bottom refection loss, which can be estimated passively by beamforming the natural surface-noise acoustic field recorded by a vertical line array of hydrophones. However, the performance in this task of arrays below 2 m of length is problematic for frequencies below 10 kHz It is shown in this paper that, when the data are free of interference from sources other than wind and wave surface noise, data from a shorter array can be used to approximate the coherence function of a longer array...
September 2016: Journal of the Acoustical Society of America
Teodora Szasz, Adrian Basarab, Denis Kouame
Beamforming (BF) in ultrasound (US) imaging has significant impact on the quality of the final image, controlling its resolution and contrast. Despite its low spatial resolution and contrast, delay-and-sum (DAS) is still extensively used nowadays in clinical applications, due to its real-time capabilities. The most common alternatives are minimum variance (MV) method and its variants, which overcome the drawbacks of DAS, at the cost of higher computational complexity that limits its utilization in real-time applications...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Saeid Aliabadi, Yuanyuan Wang, Jinhua Yu, Jinxin Zhao, Wei Guo, Shun Zhang
BACKGROUND: The Eigenspace-based beamformers, by orthogonal projection of signal subspace, can remove a large part of the noise, and provide better imaging contrast upon the minimum variance beamformer. However, wrong estimate of signal and noise component may bring dark-spot artifacts and distort the signal intensity. The signal component and noise and interference components are considered uncorrelated in conventional eigenspace-based beamforming methods. In ultrasound imaging, however, signal and noise are highly correlated...
November 24, 2016: Biomedical Engineering Online
Niranjana Vagle, Ali Broumandan, Gérard Lachapelle
Although antenna array-based Global Navigation Satellite System (GNSS) receivers can be used to mitigate both narrowband and wideband electronic interference sources, measurement distortions induced by array processing methods are not suitable for high precision applications. The measurement distortions have an adverse effect on the carrier phase ambiguity resolution, affecting the navigation solution. Depending on the array attitude information availability and calibration parameters, different spatial processing methods can be implemented although they distort carrier phase measurements in some cases...
November 17, 2016: Sensors
Maoqiang Yang, Bangning Zhang, Yuzhen Huang, Nan Yang, Daoxing Guo, Bin Gao
In this paper, we investigate the secure transmission in wireless sensor networks (WSNs) consisting of one multiple-antenna base station (BS), multiple single-antenna legitimate users, one single-antenna eavesdropper and one multiple-antenna cooperative jammer. In an effort to reduce the scheduling complexity and extend the battery lifetime of the sensor nodes, the switch-and-stay combining (SSC) scheduling scheme is exploited over the sensor nodes. Meanwhile, transmit antenna selection (TAS) is employed at the BS and cooperative jamming (CJ) is adopted at the jammer node, aiming at achieving a satisfactory secrecy performance...
November 12, 2016: Sensors
Tommaso Di Ianni, Martin Christian Hemmsen, Pere Llimos Muntal, Ivan Harald Holger Jorgensen, Jorgen Arendt Jensen
In this paper, a system-level design is presented for an integrated receive circuit for a wireless ultrasound probe, which includes analog front ends and beamformation modules. This paper focuses on the investigation of the effects of architectural design choices on the image quality. The point spread function is simulated in Field II from 10 to 160 mm using a convex array transducer. A noise analysis is performed, and the minimum signal-to-noise ratio (SNR) requirements are derived for the low-noise amplifiers (LNAs) and A/D converters (ADCs) to fulfill the design specifications of a dynamic range of 60 dB and a penetration depth of 160 mm in the B-mode image...
November 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Cagdas Tuna, Shengkui Zhao, Thi Ngoc Tho Nguyen, Douglas L Jones
Environmental noise is a risk factor for human physical and mental health, demanding an efficient large-scale noise-monitoring scheme. The current technology, however, involves extensive sound pressure level (SPL) measurements at a dense grid of locations, making it impractical on a city-wide scale. This paper presents an alternative approach using a microphone array mounted on a moving vehicle to generate two-dimensional acoustic tomographic maps that yield the locations and SPLs of the noise-sources sparsely distributed in the neighborhood traveled by the vehicle...
October 2016: Journal of the Acoustical Society of America
Giulia Matrone, Alessandro Ramalli, Alessandro Savoia, Piero Tortoli, Giovanni Magenes
Multi-Line Transmission (MLT) was recently demonstrated as a valuable tool to increase the frame rate of ultrasound images. In this approach, the multiple beams that are simultaneously transmitted may determine cross-talk artifacts that are typically reduced, although not eliminated, by the use of Tukey apodization on both transmission and reception apertures, which unfortunately worsens the image lateral resolution. In this paper we investigate the combination, and related performance, of Filtered-Delay Multiply And Sum (F-DMAS) beamforming with MLT for high frame-rate ultrasound imaging...
October 4, 2016: IEEE Transactions on Medical Imaging
Andrew D Brown, Francisco A Rodriguez, Cory D F Portnuff, Matthew J Goupell, Daniel J Tollin
In patients with bilateral hearing loss, the use of two hearing aids (HAs) offers the potential to restore the benefits of binaural hearing, including sound source localization and segregation. However, existing evidence suggests that bilateral HA users' access to binaural information, namely interaural time and level differences (ITDs and ILDs), can be compromised by device processing. Our objective was to characterize the nature and magnitude of binaural distortions caused by modern digital behind-the-ear HAs using a variety of stimuli and HA program settings...
October 3, 2016: Trends in Hearing
Jungmin Yoon, Kyoung Won Nam, Jun Chang Lee, Dong Pyo Jang, In Young Kim
For hearing-impaired individuals with neurological motor deficits or finger/arm amputation due to accident or disease, hearing aid adjustment using a conventional finger manipulation-based remote controller is unavailable, and a more dedicated, hands-free alternative is required. In this study, we propose an eye-blinking-based beamforming control scheme for hearing aid users. Three electroencephalogram signals measured around the ears were utilized to detect eye-blinking patterns based on a three-layer artificial neural network...
September 21, 2016: Artificial Organs
Elahe Moghimirad, Carlos A Villagomez Hoyos, Ali Mahloojifar, Babak Mohammadzadeh Asl, Jorgen Arendt Jensen
An efficient Fourier beamformation algorithm is presented for multistatic synthetic aperture ultrasound imaging using virtual sources. The concept is based on the frequency domain wavenumber algorithm from radar and sonar and is extended to a multielement transmit/receive configuration using virtual sources. Window functions are used to extract the azimuth processing bandwidths and weight the data to reduce side lobes in the final image. Field II simulated data and SARUS (Synthetic Aperture Real-time Ultrasound System) measured data are used to evaluate the results in terms of point spread function, resolution, contrast, signal-to-noise ratio, and processing time...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Nghia Q Nguyen, Richard W Prager, Michael F Insana
A task-based approach is employed to develop an analytical framework for ultrasound beamformer design and evaluation. In this approach, a Bayesian ideal-observer provides an idealized starting point and a way to measure information loss in practical beamformer designs. Different approximations of this ideal strategy are shown to lead to popular beamformers in the literature, including the matched filter, minimum variance (MV), and Wiener filter (WF) beamformers. Analysis of the approximations indicates that the WF beamformer should outperform the MV approach, especially in low echo signal-to-noise conditions...
August 2016: Journal of the Acoustical Society of America
Yuxiang Hu, Haoran Zhou, Jing Lu, Xiaojun Qiu
Beamformers enable a microphone array to capture acoustic signals from a sound source with high signal to noise ratio in a noisy environment, and the linear microphone array is of particular importance, in practice, due to its simplicity and easy implementation. A linear microphone array sometimes is used near some scattering objects, which affect its beamforming performance. This paper develops a numerical model with a linear microphone array near a rigid sphere for both far-field plane wave and near-field sources...
August 2016: Journal of the Acoustical Society of America
Che-Chou Shen, Yong-Qi Xing, Gency Jeng
BACKGROUND: Generalized coherence factor (GCF) can be adaptively estimated from channel data to suppress sidelobe artifacts. Conventionally, Fast Fourier Transform (FFT) is utilized to calculate the full channel spectrum and suffers from high computation load. In this work, autocorrelation (AR)-based algorithm is utilized to provide the spectral parameters of channel data for GCF estimation with reduced complexity. METHODS: Autocorrelation relies on the phase difference among neighboring channel pairs to estimate the mean frequency and bandwidth of channel spectrum...
December 2016: Ultrasonics
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