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The image quality provided by current ultrasound (US) scanners can be increased by extending the effective bandwidth of the US transducers. In 2007, a promising technique, called Resolution Enhancement Compression (REC), was proposed. Combining chirp modulated signals in emission and Modified Wiener Filters (MTF) in reception, REC allows bandwidth enhancement by boosting the energy of the emitted/received...
A row-column-addressed (RCA) 2-D array can be interpreted as two orthogonal 1-D arrays. Since the transmit and receive 1-D arrays are orthogonal to each other, only one-way focusing is possible in each transmit or receive plane. By transmitting with row elements and receiving the echoes through column elements, a rectilinear volume in front of the array can be beamformed. This study suggests to use...
In the last decade the number of beamforming methods has exploded. Many innovative ideas have been proposed, but we lack the tools to compare the different techniques efficiently. The PICMUS challenge (IUS 2016, Tours) was a pioneering step that made clear that two things are required to establish a fair comparison: a common data format, and a body of methods to process that data.
Plane-wave imaging plays a highly significant role o wing to the special demand for high frame rate, however, its po or image quality hinders its application in ultrasound industrie s. Many scholars have attempted to give a wide variety of soluti ons to improve the image quality, however, each of them has li mitations or compromises. In this study, we improve the spatio -temporally smoothed factor...
We have developed a new, fast and simple 3D imaging approach referred to as Simultaneous Azimuth and Fresnel Elevation (SAFE) compounding. The principle behind this technique is to perform conventional plane wave compounding with the bottom set of electrodes, while implementing a reconfigurable Fresnel elevation lens with the top electrodes. While a Fresnel lens would usually result in unacceptable...
In this paper, we present a front-end integrated circuit (IC) for an ultrasound neurostimulation system, to be interfaced with a 16×16 2D CMUT array to realize an ultrasound field pattern (USFP) using quantized phases and amplitudes. The IC uses a pulse width modulation (PWM) technique with a three-level pulse to generate excitation signals having multi-level quantized amplitudes. For a programmable...
As the medical ultrasound signals are not stationary, the radiation pattern of the corresponding input data does not have a specific shape. Thus, their reconstruction using adaptive beamformer (BF) become indispensable in order to improve the quality of the image. Generalized Side Lobe Canceller (GSC) is a robust realization against clutter and interference, resulting from an elegant representation...
3D Ultrasound systems present several technical challenges, particularly the large number of elements in a 2D array, high electrical impedance, and image acquisition time. Crossed electrode arrays address some of these issues, especially the huge reduction in number of elements. However, creating a two-way focused 3D image in real-time is difficult with these arrays because azimuth and elevation dimensions...
Non-contrast blood perfusion imaging with ultrasound is difficult due to tissue clutter caused by patient physiological and sonographer hand motion. This motion causes spectral broadening of the tissue clutter signal, which then overlaps with the perfusion signal. To address this problem, we previously introduced an adaptive frequency and amplitude demodulation scheme to reduce the bandwidth of the...
To improve the quality of focused ultrasound images, in the last decade several beamforming algorithms have been proposed as an alternative to the common Delay-And-Sum (DAS), as for example adaptive or non-linear beamformers, which achieve improved imaging performance at the expense of an increased computational load. In this paper, we propose a computationally efficient algorithm based on nonlinear...
A hybrid beamforming approach combining the strengths of diverging wave compounding (DWC) and multi-line-transmit beamforming (MLT) (i.e., multi-plane-transmit, MPT) was previously proposed by our labs for 3D imaging [1]. Although we demonstrated this approach to be superior to 3D DWC and 3D MLT, we did not account for artifacts induced by motion. The aim of this study was therefore to propose a motion...
Currently there are two main categories of adaptive beamforming applied to medical ultrasound imaging: minimum-variance-related beamforming(MV) and coherence-factor-related beamforming (CF), both of which have been applied to suppress side/granting lobe and clutter for plane-wave imaging. Unfortunately, due to low SNR/SINR, the resulting images may suffer from deficiencies: deteriorated speckle pattern,...
We have designed and implemented an ultrasonic imaging research platform that performs all signal processing, including beamforming and image processing, using software on a GPU. An operating software is developed on a PC that can control RF data acquisition hardware to accommodate ultrasound images of various formats. Beamforming methods that include conventional scan line based imaging, scan line-based...
3D diverging wave compounding (DWC) was recently demonstrated to be capable of providing high-frame-rate imaging, but at the risk of introducing motion artifacts. As an alternative, a hybrid beamforming approach combining the features of DWC and multi-line-transmit (MLT) beamforming was proposed (i.e., multi-plane-transmit, MPT), showing some superiority when compared with 3D DWC [1]. However, in...
An ultrasonic array system is designed for wirelessly powering and communicating with implantable medical devices. A flexible hardware interface is used to drive a 32-element linear phased array with emphasis on programmability and efficiency rather than bandwidth or peak power. Various beam patterns and data modulation schemes are verified at a depth of 6 cm in a tissue phantom with more than sufficient...
Transcranial Doppler Ultrasound (TCD) is a non-invasive approach that has been used in both diagnosis and therapy of stroke. However, current TCD devices are highly operator dependent and a 2D sparse array transducer can help reduce the operator dependency with its improved imaging and focusing capabilities. This paper compares the potential of three aperiodic sparse array configurations: random array;...
The technique of non-invasive cortical bone quality assessment using ultrasound axial transmission has attracted considerable attention. Estimating the phase velocity and the attenuation of the absorbing plate will assist the assessment. Among several techniques proposed for these purposes, many employ either a thresholding process or a peak search process. The thresholding process uses the intensity...
Off-axis clutter is a significant cause of image degradation in ultrasound. Adaptive weighting methods based on signal coherence, and adaptive beamforming approaches based on signal direction of arrival, have been proposed to address this problem. Clutter removal is also an important component of pre-processing prior to flow estimation, and adaptive clutter filters based on singular value decomposition...
Ultrafast imaging based on coherent plane-wave compounding improves image quality and allows for much faster acquisition. This method, however, is limited by severe computational loads stemming from delay-and-sum beamforming (DAS BF) that creates a major bottleneck for real-time implementation. Spatial-temporal (ST) processing yields the entire frame without a need for DAS BF of each image line. First,...
A dual beam vector Doppler method was proposed (DOI: 10.1016/j.ultrasmedbio.2009.11.004), in which one beam is continuously tracked perpendicular to the flow direction, and the second one is used to perform velocity measurements with known Doppler angle. Since two consecutive transmission (TX) and reception (RX) events (one for each beam) are needed, the effective Doppler pulse repetition frequency...
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