scholarly journals Two-Dimensional Random Arrays for Real Time Volumetric Imaging

1994 ◽  
Vol 16 (3) ◽  
pp. 143-163 ◽  
Author(s):  
R Davidsen
Keyword(s):  
Real Time ◽  
Two Dimensional ◽  
Volumetric Imaging ◽  
Random Arrays

A two‐dimensional amplitude‐steered array for real‐time volumetric imaging

2001 ◽  
Vol 109 (5) ◽  
pp. 2360-2360
Author(s):  
Catherine H. Frazier ◽  
W. Jack Hughes ◽  
William D. O’Brien
Keyword(s):  
Real Time ◽  
Two Dimensional ◽  
Volumetric Imaging

Progress in Two-Dimensional Arrays for Real-Time Volumetric Imaging

1998 ◽  
Vol 20 (1) ◽  
pp. 1-15 ◽  
Author(s):  
E. D. Light ◽  
R. E. Davidsen ◽  
J.O. Fiering ◽  
T. A. Hruschka ◽  
S. W. Smith
Keyword(s):  
Real Time ◽  
Insertion Loss ◽  
Imaging System ◽  
Two Dimensional ◽  
Volumetric Imaging ◽  
Dimensional Array ◽  
Transducer Arrays ◽  
Volumetric Images ◽  
Duke University

The design, fabrication, and evaluation of two dimensional array transducers for real-time volumetric imaging are described. The transducers we have previously described operated at frequencies below 3 MHz and were unwieldy to the operator because of the interconnect schemes used in connecting to the transducer handle. Several new transducers have been developed using new connection technology. A 40 × 40 = 1,600 element, 3.5 MHz array was fabricated with 256 transmit and 256 receive elements. A 60 × 60 = 3,600 element 5.0 MHz array was constructed with 248 transmit and 256 receive elements. An 80 × 80 = 6,400 element, 2.5 MHz array was fabricated with 256 transmit and 208 receive elements. 2-D transducer arrays were also developed for volumetric scanning in an intracardiac catheter, a 10 × 10 = 100 element 5.0 MHz forward-looking array and an 11 × 13 = 143 element 5.0 MHz side-scanning array. The −6 dB fractional bandwidths for the different arrays varied from 50% to 63%, and the 50 Ω insertion loss for all the transducers was about −64 dB. The transducers were used to generate real-time volumetric images in phantoms and in vivo using the Duke University real time volumetric imaging system, which is capable of generating multiple planes at any desired angle and depth within the pyramidal volume.

scholarly journals Two-Dimensional Random Arrays for Real Time Volumetric Imaging

1994 ◽  
Vol 16 (3) ◽  
pp. 143-163 ◽  
Author(s):  
Richard E. Davidsen ◽  
Jørgen A. Jensen ◽  
Stephen W. Smith
Keyword(s):  
Uniform Distribution ◽  
Real Time ◽  
Imaging System ◽  
Frame Rate ◽  
Depth Of Field ◽  
System Response ◽  
Two Dimensional ◽  
Volumetric Imaging ◽  
Sparse Array ◽  
Random Array

Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been considered with element geometries selected ad hoc, by algorithm, or by random process. Two random sparse array geometries and a sparse array with a Mills cross receive pattern were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth-of-field comparisons were made from simulated on-axis and off-axis beamplots at ranges from 30 to 160 mm for both coaxial and offset transmit and receive beams. A random array with Gaussian distribution of transmitters and uniform distribution of receivers was found to have better resolution and depth-of-field than both a Mills cross array and a random array with uniform distribution of both transmit and receive elements. The Gaussian random array was constructed and experimental system response measurements were made at several ranges. Comparisons of B-scan images of a tissue mimicking phantom show improvement in resolution and depth-of-field consistent with simulation results.

Two-dimensional catheter arrays for real-time intracardiac volumetric imaging

1999 ◽  
Author(s):  
Edward D. Light ◽  
Jason O. Fiering ◽  
Warren Lee ◽  
Patrick D. Wolf ◽  
Stephen W. Smith
Keyword(s):  
Real Time ◽  
Two Dimensional ◽  
Volumetric Imaging

CALCULATION OF THE DEPENDENCE OF THE DISTANCE TO THE LOCATED OBJECT FROM THE CORNER POSITION OF THE VEHICLE LINE

2018 ◽  
pp. 14-18
Author(s):  
V. V. Artyushenko ◽  
A. V. Nikulin
Keyword(s):  
Real Time ◽  
Statistical Physics ◽  
Angular Position ◽  
Three Dimensional ◽  
Line Of Sight ◽  
Two Dimensional ◽  
Radar Station ◽  
Flight Mode ◽  
Vector Algebra ◽  
Analytical Expressions

To simulate echoes from the earth’s surface in the low flight mode, it is necessary to reproduce reliably the delayed reflected sounding signal of the radar in real time. For this, it is necessary to be able to calculate accurately and quickly the dependence of the distance to the object being measured from the angular position of the line of sight of the radar station. Obviously, the simplest expressions for calculating the range can be obtained for a segment or a plane. In the text of the article, analytical expressions for the calculation of range for two-dimensional and three-dimensional cases are obtained. Methods of statistical physics, vector algebra, and the theory of the radar of extended objects were used. Since the calculation of the dependence of the range of the object to the target from the angular position of the line of sight is carried out on the analytical expressions found in the paper, the result obtained is accurate, and due to the relative simplicity of the expressions obtained, the calculation does not require much time.

Accelerating laser processes with a smart two-dimensional polygon mirror scanner for ultra-fast beam deflection

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Florian Roessler ◽  
André Streek
Keyword(s):  
Energy Distribution ◽  
Real Time ◽  
Laser Processing ◽  
High Speed ◽  
Beam Deflection ◽  
Two Dimensional ◽  
Heat Accumulation ◽  
Field Programmable ◽  
Drill Holes ◽  
Average Laser

Abstract In laser processing, the possible throughput is directly scaling with the available average laser power. To avoid unwanted thermal damage due to high pulse energy or heat accumulation during MHz-repetition rates, energy distribution over the workpiece is required. Polygon mirror scanners enable high deflection speeds and thus, a proper energy distribution within a short processing time. The requirements of laser micro processing with up to 10 kW average laser powers and high scan speeds up to 1000 m/s result in a 30 mm aperture two-dimensional polygon mirror scanner with a patented low-distortion mirror configuration. In combination with a field programmable gate array-based real-time logic, position-true high-accuracy laser switching is enabled for 2D, 2.5D, or 3D laser processing capable to drill holes in multi-pass ablation or engraving. A special developed real-time shifter module within the high-speed logic allows, in combination with external axis, the material processing on the fly and hence, processing of workpieces much larger than the scan field.

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