A new 2D (two-dimensional) and 3D (three-dimensional) pulse-echo imaging method (Fourier method) has been developed with limited diffraction beams. In this method, a plane wave pulse (broadband) is used to transmit beams of different parameters are receive. Signals received processed obtain spatial Fourier transform object functions images constructed an inverse transform. Because only one transmission required construct images, may achieve high frame rate (up 3750 frames/s for biological...

Fast three-dimensional (3-D) ultrasound imaging is a technical challenge. Previously, high-frame rate (HFR) theory was developed in which pulsed plane wave used transmission, and limited-diffraction array beam weightings were applied to received echo signals produce spatial Fourier transform of object function for 3-D image reconstruction. In this paper, the extended include explicitly various transmission schemes such as multiple beams steered waves. A relationship between weighting 2-D...

Limited diffraction beams have a large depth of field and many potential applications. Recently, new method (Fourier method) was developed with limited for image construction. With the single plane wave transmission, both 2D (two-dimensional) 3D (three-dimensional) images very high frame rate (up to 3750 frames/s 200 mm in biological soft tissues) signal-to-noise ratio (SNR) can be constructed relatively simple inexpensive hardware. If different parameters are used transmission reception...

A general-purpose high frame rate (HFR) medical imaging system has been developed. This 128 independent linear transmitters, each of which is capable producing an arbitrary broadband (about 0.05-10 MHz) waveform up to +/- 144 V peak voltage on a 75-ohm resistive load using 12-bit/40-MHz digital-to-analog converter. The also independent, 0.25-10 MHz), and time-variable-gain receiver channels, analog-to-digital converter 512 MB memory. controlled by personal computer (PC), radio frequency echo...

Mapping wave field in space has many applications such as optimizing design of radio antennas, improving and developing ultrasound transducers, planning monitoring the treatment tumors using high-intensity focused (HIFU). Currently, there are methods that can map fields remotely or locally. However, limitations with these methods. For example, when mapping remotely, spatial resolution is limited due to a poor diffractionlimited receiver, especially f-number receiver large. To locally, either...

Bessel beams are exact solutions to the isotropic/homogeneous wave equation. In theory, they can propagate infinite distance without diffraction. practice, when produced with a finite aperture, have very large depth of field, i.e., maintain small beamwidth over distance. addition, self-healing ability after encountering an obstacle. Because these properties, applications in optics, electromagnetics, ultrasound, quantum communications, electron beam guidance, and so on. Previously, were...

Theoretically, limited diffraction beams can only be produced with an infinite aperture. In practice, they closely approximated a finite aperture over large depth of field. Because this property, these could have applications in medical imaging, tissue characterization, Doppler velocity estimation, and nondestructive evaluation (NDE) materials, as well other physics-related areas such electromagnetics optics. paper, new method is developed to design desired beam shapes within interest. It...

The spatial resolution of an imaging system using waves is limited by the bandwidth point spread function (PSF) system, which related to wavelength. However, when PSF modulated either in amplitude or phase both, resulting increased. In this study, PSF-modulation method used obtain super-resolution objects and distinguish wave sources that are closely located space not normally separable due diffraction limit. waves, such as ultrasound, acoustics, optics, electromagnetics, radar, sonar, can...

Conventional focused transducers have a sharp focal spot with low sidelobes, but they also short depth of field. Commercial medical scanners obtain increased field by combining several images in montage, each obtained at different depth. Therefore, to get sidelobes over large transmits must be used, which decrease the frame rate. Limited diffraction beams such as Bessel and X waves good resolution very field, high sidelobes. A summation-subtraction method developed for decreasing is...

Limited diffraction beams have a large depth of field and could many applications. In this article, new limited are developed. They composed multiple parallel thus called array beams. A broadband synthetic experiment is used to produce these finite aperture, results in excellent agreement with theory over field. addition, potential applications the real-time volumetric imaging measurement transverse velocity blood flow described. © 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 126–136,

Limited diffraction beams such as Bessel and X waves have a large depth of field thus could many applications. However, these higher sidelobes compared to conventional focused in their focal planes. In this paper, new class limited is developed. These are termed bowtie because they shapes plane perpendicular the beam axis. To obtain pulse-echo images low field, used transmission its 90/spl deg/ rotated response (around axis) reception. Unlike summation-subtraction method developed...

Limited-diffraction beams have a large depth of field and could be applied to medical imaging, tissue characterization, nondestructive evaluation materials. This paper reports the application limited-diffraction beams, specifically, Bessel beam, Doppler velocity estimation. The beam has advantage that estimation is less subject moving objects spectrum distinct shoulders increase accuracy (both magnitude angle) in noisy environments. might also help solving inverse problem, e.g., distribution...

The authors describe a method for estimating backscatter coefficients of excised human liver samples and the RMI413A tissue equivalent phantom, using J/sub 0/ Bessel nondiffracting transducer. A formula calculation that requires only two one-dimensional integrations in addition to Fourier transforms is presented. This equation combination with from beam results ability calculate real time. In addition, estimations are more distance-independent because nonspreading nature beam. present...

A method is developed for calculating fields produced with a two-dimensional (2D) array transducer. This decomposes an arbitrary 2D aperture weighting function into set of limited diffraction beams. Using the analytical expressions beams, continuous wave (cw) or pulse (pw) arrays can be obtained simple superposition these In addition, this simplified and applied to 1D transducer finite infinite elevation height. For beams axially symmetric functions, reduced Fourier-Bessel studied previously...

Based on the high frame rate (HFR) imaging method developed in our lab, an extended with various transmission schemes was recently. In this method, multiple, limited- diffraction array beams or steered plane wave transmissions are used to increase image resolution and field of view as well reduce sidelobes. Furthermore, limited-diffraction beam can be approximated square-wave aperture weightings, allowing one two transmitters a multielement transducer simplify systems. By varying number...

Traditional methods for water treatment are not effective to remove micro pollutants such as harmful organics and cannot meet the demand high-quality drinking water. Membrane technologies known produce of highest quality. However, membrane fouling is a significant problem, which limits widespread use these technologies. Currently, chemical cleaning used control fouling, interrupts production process during cleaning, produces secondary pollutants, shortens life due erosion, adds costs...

Analytical solutions were obtained for limited diffraction beams such as Bessel and X waves, well conventional plane wave, with or without focus in both rectangular polar coordinates. Using a focused wave transmit beam receive, high-resolution C-mode image that breaks the limit of was using source 50-mm diameter, 2.5-MHz frequency, focal length, 0.6-mm wavelength an object at focus. The two-way (pulse-echo) full-width-at-half-maximum (FWHM) lateral resolution 0.56 mm. As comparison, FWHM...

Limited diffraction beams could have applications in medical imaging, tissue characterization, and nondestructive evaluation, as well other wave related areas such electromagnetics optics. In this paper, we develop a novel approach that can convert any diffracting solution of the isotropic-homogeneous equation to limited solution. As an example, was applied n-dimensional wavelet generalized from three-dimensional obtained by Kaiser et al. (1992). This example establishes relationship between...

Limited diffraction beams have a large depth of field and could applications in medical ultrasound other wave related areas such as electromagnetics optics. However, these higher sidelobes than conventional focused at their focuses. Recently, new type beam, called bowtie limited beams, was developed. These can achieve both low imaging. In this paper, the production water with synthetic array experiment is reported. A broad-band PZT ceramic/polymer composite transducer about 1 mm diameter 2.5...