Ultrasonic Lamb modes typically propagate as a combination of multiple dispersive wave packets. Frequency components each mode distribute widely in time domain due to dispersion and it is very challenging separate individual by traditional signal processing methods. In the present study, method compensation proposed for purpose separation. This numerical compensates, i.e., compresses, waveforms into temporal pulses, which thereby become nearly un-overlapped frequency can thus be extracted...

The 2-D Fourier transform analysis of multichannel signals is a straightforward method to extract the dispersion curves guided modes. Basically, time recorded at several positions along waveguide are converted wavenumber-frequency space, so that (i.e., frequency-dependent wavenumbers) modes can be extracted by detecting peaks energy trajectories. In order improve curve extraction low-amplitude propagating in cortical bone, multiemitter and multireceiver transducer array has been developed...

Quantitative ultrasound has great potential for assessing human bone quality. Considered as an elastic waveguide, long supports propagation of several guided modes, most which carry useful information, individually, on different aspects properties. Therefore, precise knowledge the behavior each mode, such velocity, attenuation, and amplitude, is important quality assessment. However, because complicated characteristics waves, including dispersion mode conversion, measured signal often...

Effective tissue clutter filtering and noise removing are essential for ultrafast Doppler imaging. Singular vector decomposition (SVD)-based spatiotemporal method has been applied as a classical to remove the strong motion artifacts. However, performance of SVD-based methods often depends on proper eigenvector thresholding, i.e., separation signal subspaces small-value blood flow, large-value static tissue, noise. In study, Cauchy-norm-based robust principal component analysis (Cauchy-RPCA)...

Ultrafast Doppler has been accepted as a novel modality for small vasculature imaging with high sensitivity, spatiotemporal resolution, and penetration. However, the conventional estimator adopted in studies of ultrafast ultrasound is only sensitive to velocity component along beam direction angle-dependent limitations. Vector developed goal angle-independent estimation but typically employed relatively large vessels. In this study, combining multiangle vector strategy sequencing, (ultrafast...

Acoustic matching layers play an important role in ultrasonic transducers. However, the acoustic layer with both intrinsic flexibility and high impedance remains unmet need to achieve high-performing flexible Herein, we present epoxy/nano-zirconia composite excellent performance by chemical coupling method. (3-Aminopropyl)triethoxysilane was used effectively disperse nano-zirconia particles epoxy resin, endow resultant flexibility. After carefully adjusting additions of...

Extensive studies have reported that cocaine can lead to potent reduction in cerebral blood flow. However, the mechanisms of cocaine's impact on neural and vascular system brain temporal spatial aspects remain elusive. Functional ultrasound (fUS) is a novel neurovascular imaging modality acclaimed for its deep penetration, superior spatiotemporal resolution, high sensitivity small flow dynamics. This study aims use fUS technique characterize regional differences hemodynamic responses acute...

Ultrasound imaging of musculoskeletal tissue has long been a challenge. As novel medical ultrasound computed tomography (UCT) technique, full-waveform inversion (FWI) provides promising solution for with high spatial resolution. However, FWI suffers from substantial computational burden, primarily due to the multiple wavefield calculations involved in process, especially when dealing large number sources. In order minimize calculations, we propose source encoding technology FWI. detail,...

A spectrum-domain method, called full-matrix phase shift migration (FM-PSM), is presented for transcranial ultrasound correction and imaging with ideal synthetic aperture focusing technology. The simulated data obtained using the pseudospectral time-domain method are used to evaluate feasibility of method. experimental measured from a 3-D printed skull phantom algorithm performance in terms resolution, contrast-to-noise ratio (CNR), eccentricity comparing classical ray-tracing delay sum...

Ultrasonic guided waves (UGWs) propagating in the long cortical bone can be measured via axial transmission method. The characterization of using UGW is a multiparameter inverse problem. optimal solution problem often includes complex solving process. Deep neural networks (DNNs) are essentially powerful predictors based on universal approximation theorem, which suitable for parameter predictions by constructing mapping relationship between and material parameters. In this study, we...

Ultrasonic guided waves have been widely acknowledged as the most promising tools for nondestructive evaluation (NDE). However, because of multimodal dispersion, received modes usually overlap in both time and frequency, which highly complicates mode separation signal interpretation. The time-reversal technique can be used to realize recompression Lamb waves, but multimode excitation reception, it still may not able remove ambiguity achieve pure pulse compression. With goal overcoming this...

Dispersion results in the spreading and overlapping of wave-packets, which often limits capability signal interpretation; on other hand, such a phenomenon can also be used for structure or media evaluation. In this study, authors propose an original dispersive Radon transform (DRT), is formulated as integration along set dispersion curves. Multichannel signals each individual mode concentrated to well localized region DRT domain. The proposed establishes sparse projection components provides...