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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...
Ultrasound is a widely used imaging modality, both for diagnosis and guidance of interventional procedures such as biopsies. Ultrasound imaging commonly provides 2D data, which can be a limitation for further data processing, since information like out-of-plane motion is inaccessible. In this study, a specific multi-row array transducer — developed for the elastography application — is presented....
Data acquisition from 2-D transducer arrays has become one of the main challenges for the development of endoscopic and catheter-based 3-D ultrasound imaging devices. Front-end ASICs with sub-array pre-beamforming have been reported that reduce the cable number by an order of magnitude. Further channel reduction requires digitization in the front-end ASIC to facilitate more in-probe data processing...
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...
Bio-medical ultrasound imaging has recently gained considerable attention. A two-dimensional (2-D) array is essential for three-dimensional (3-D) volumetric imaging. Fully populated 2-D dense array requires thousands of active elements and their interconnections. We present a 2-D CMUT sparse array with 128 elements for 3-D volumetric imaging. This CMUT sparse array with a die size of 6.3 mm × 6.3...
Ultrasound (US) therapy is, for a large panel of application, a promising technique which still requires an accurate monitoring system. Therefore, the passive acoustic mapping (PAM) beamforming technique is outlined. It reconstructs cavitation activity maps by beamforming acoustic signals passively recorded by an array. This method has already been explored in 2D with optimizations as phase coherence...
In this work, an all-optical ultrasound imaging system that is capable of synthesising arbitrary source aperture geometries is presented. This capability is achieved by delivering focussed excitation light onto a spatially extended generating surface, where ultrasound is generated photoacoustically. Using a scanning mirror, the position of the resulting acoustical source was continuously varied to...
In the past, members of our group developed a model based beamforming method called aperture domain model image reconstruction (ADMIRE). They tuned ADMIRE to improve ultrasound image quality by suppressing sources of image degradation such as off-axis scattering, reverberation, and phase aberration. In addition, the development of ADMIRE demonstrated that beamforming could be posed as a regularized...
As medical ultrasound (MU) signals are not stationary, the radiation pattern of the corresponding input data does not have a specific shape; thus, their reconstruction using Adaptive Beamformers (BF) becomes indispensable in order to improve the quality of the imaging system. Generalized Sidelobe Canceller (GSC) is a robust realization against clutter and interference, resulting from an elegant representation...
Today, 3-D vector flow imaging (VFI) in a full volume requires a fully populated NxN 2-D matrix array if a sufficient frame rate should be maintained. Such arrays require an expensive ultrasound system, which can handle the enormous data stream created by the N2 channels. As an alternative to the matrix array, N+N 2-D row-column addressed (RCA) arrays were introduced, which reduce the channel count...
Electromechanical wave imaging (EWI) is an ultrasound-based methodology that can map the electromechanical activation of the heart at high temporal resolution. Previous reports have shown strong correlation between EWI-based and electrical activation times. However, EWI has been performed only with 2D echocardiography, which cannot map the full cardiac volume in a single heartbeat. Our objective in...
We present a fully-populated 8×8 2D-phased array, capable of emitting directed air-coupled ultrasound at 40 kHz with λ/2-pitch size for zero grating lobes. In comparison to our previous work, in which we describe a 1D-phased array, we use 3D-printing to realize the wave guide structure. Besides the key idea to separate the vibrating from the acoustic aperture, the 3D-printing approach allows implementing...
A novel ultrasound (US) platform with high channels density that offers flexibility, precision and open access is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of new enabled advanced techniques: dual-mode US imaging/therapies in the heart, new approaches to study the myocardial tissue (structure/characterization), fast sparse array strategies, multi-line...
A dual-mode ultrasound array (DMUA) imaging system for monitoring and delivery of transcranial focused ultrasound (tFUS) therapy is described. A DMUA prototype operating in the frequency range 2.4 – 4.2 MHz has been shown to generate tFUS beams at therapeutic levels in rat brains in vivo based on two-dimensional image guidance. Furthermore, real-time ultrasound thermography was shown to be feasible...
Passive beamforming in ultrasound therapy monitoring strives to estimate the energy emanating from a near-field source location by “steering” the wideband sensor signals with time delays, summing the steered signals, and computing the energy over a time interval. An image of the spatial energy distribution is obtained by repeating the process over a grid of imaging locations. Capon beamforming provides...
We are developing a capsule ultrasound (CUS) device - a pill with the capability to scan the gastrointestinal (GI) tract through ultrasound. In this paper, we discuss the design and fabrication of the main components of the CUS device including the CMUT array, front-end electronics, and the wireless transmitter. We demonstrate a successfully fabricated 128-element CMUT array with polydimethylsiloxane...
In this paper, a multi-aperture synthetic focusing technique based on virtual source is studied, which improves the lateral resolution and depth of the ultrasonic imaging with respect to the single array dynamic synthetic aperture focusing technique (SAFT). It only needs to store the N numbers data for the A scan line, and the complexity of the algorithm is greatly reduced compared with the full focus...
The paper presents a method of reducing the matrix that keeps the distance which went ultrasound and an data processing algorithm for the phased array system using MatLab. Cut of the control object for the phased array containing of 16 sensors is presented. Also The paper presents an example of practical realization of the algorithm on an FPGA using the program Quartus II.
There is an undisputed need for increased portability and flexibility in diagnostic ultrasound imaging due to the continuously evolving point of care (POC) clinical applications. In order to meet this growing need numerous portable ultrasound systems have been proposed. The design of portable systems is a very challenging task, especially for volumetric imaging system which utilize transducers with...
We introduce a versatile one-dimensional (1D) air-coupled phased array transducer device operating at 40 kHz. It allows both — transmit beam steered ultrasound at high sound pressure level and it can sense beam steered ultrasound. This device opens the door to many new sensory applications. Conventionally, low frequency sensor array design for air-coupled application was not possible due to the inter...
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