How crystal configuration affects the position detection accuracy in pixelated molecular SPECT imaging systems?

2017 ◽  
Vol 28 (4) ◽  
Author(s):  
Hojjat Mahani ◽  
Gholamreza Raisali ◽  
Alireza Kamali-Asl ◽  
Mohammad Reza Ay
Keyword(s):  
Spect Imaging ◽  
Imaging Systems ◽  
Detection Accuracy ◽  
Position Detection

scholarly journals The nanofluidic confinement apparatus: studying confinement-dependent nanoparticle behavior and diffusion

2018 ◽  
Vol 9 ◽  
pp. 301-310 ◽  
Author(s):  
Stefan Fringes ◽  
Felix Holzner ◽  
Armin W Knoll
Keyword(s):  
Polymer Surface ◽  
Diffusion Constant ◽  
Numerical Aperture ◽  
Lateral Diffusion ◽  
Vertical Position ◽  
Detection Accuracy ◽  
Illumination Time ◽  
Electroviscous Effect ◽  
Position Detection ◽  
Hydrodynamic Effects

The behavior of nanoparticles under nanofluidic confinement depends strongly on their distance to the confining walls; however, a measurement in which the gap distance is varied is challenging. Here, we present a versatile setup for investigating the behavior of nanoparticles as a function of the gap distance, which is controlled to the nanometer. The setup is designed as an open system that operates with a small amount of dispersion of ≈20 μL, permits the use of coated and patterned samples and allows high-numerical-aperture microscopy access. Using the tool, we measure the vertical position (termed height) and the lateral diffusion of 60 nm, charged, Au nanospheres as a function of confinement between a glass surface and a polymer surface. Interferometric scattering detection provides an effective particle illumination time of less than 30 μs, which results in lateral and vertical position detection accuracy ≈10 nm for diffusing particles. We found the height of the particles to be consistently above that of the gap center, corresponding to a higher charge on the polymer substrate. In terms of diffusion, we found a strong monotonic decay of the diffusion constant with decreasing gap distance. This result cannot be explained by hydrodynamic effects, including the asymmetric vertical position of the particles in the gap. Instead we attribute it to an electroviscous effect. For strong confinement of less than 120 nm gap distance, we detect the onset of subdiffusion, which can be correlated to the motion of the particles along high-gap-distance paths.

Solid geometrv based modelling of non-uniform attenuation and compton scattering in objects for SPECT imaging systems

1993 ◽  
Vol 40 (4) ◽  
pp. 1305-1312 ◽  
Author(s):  
Huili Wang ◽  
Ronald J. Jaszczak ◽  
David R. Gilland ◽  
Kim L. Greer ◽  
R. Edward Coleman
Keyword(s):  
Compton Scattering ◽  
Spect Imaging ◽  
Imaging Systems

Position detection accuracy of a novel linac-mounted intrafractional x-ray imaging system

2011 ◽  
Vol 39 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Martin F. Fast ◽  
Andreas Krauss ◽  
Uwe Oelfke ◽  
Simeon Nill
Keyword(s):  
Imaging System ◽  
Detection Accuracy ◽  
X Ray ◽  
Position Detection ◽  
X Ray Imaging

scholarly journals Improvement of Position Detection Accuracy Utilizing the Antenna Directivity of the Position Detector for Capsule Endoscope

2021 ◽  
Vol 29 (2) ◽  
pp. 212-218
Author(s):  
Ryoken MASUDA ◽  
Ryoga YUZAWA ◽  
Mitsuhide SATO ◽  
Tsutomu MIZUNO ◽  
Kunihisa TASHIRO ◽  
...  
Keyword(s):  
Detection Accuracy ◽  
Capsule Endoscope ◽  
Position Detection ◽  
Antenna Directivity

scholarly journals Lane Position Detection Based on Long Short-Term Memory (LSTM)

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3115
Author(s):  
Wei Yang ◽  
Xiang Zhang ◽  
Qian Lei ◽  
Dengye Shen ◽  
Ping Xiao ◽  
...  
Keyword(s):  
Spatial Information ◽  
Short Term Memory ◽  
Driving Safety ◽  
Detection Accuracy ◽  
Short Term ◽  
Distribution Law ◽  
Position Information ◽  
Term Memory ◽  
Position Detection ◽  
Long Short Term Memory

Accurate detection of lane lines is of great significance for improving vehicle driving safety. In our previous research, by improving the horizontal and vertical density of the detection grid in the YOLO v3 (You Only Look Once, the 3th version) model, the obtained lane line (LL) algorithm, YOLO v3 (S × 2S), has high accuracy. However, like the traditional LL detection algorithms, they do not use spatial information and have low detection accuracy under occlusion, deformation, worn, poor lighting, and other non-ideal environmental conditions. After studying the spatial information between LLs and learning the distribution law of LLs, an LL prediction model based on long short-term memory (LSTM) and recursive neural network (RcNN) was established; the method can predict the future LL position by using historical LL position information. Moreover, by combining the LL information predicted with YOLO v3 (S × 2S) detection results using Dempster Shafer (D-S) evidence theory, the LL detection accuracy can be improved effectively, and the uncertainty of this system be reduced correspondingly. The results show that the accuracy of LL detection can be significantly improved in rainy, snowy weather, and obstacle scenes.

TU-C-214-08: Position Detection Accuracy of a Novel Linac-Mounted Intra-Fractional X-Ray Imaging System

2011 ◽  
Vol 38 (6Part28) ◽  
pp. 3757-3758
Author(s):  
M Fast ◽  
A Krauss ◽  
S Nill ◽  
U Oelfke
Keyword(s):  
Imaging System ◽  
Detection Accuracy ◽  
X Ray ◽  
Position Detection ◽  
X Ray Imaging

scholarly journals An Improved Method for Spot Position Detection of a Laser Tracking and Positioning System Based on a Four-Quadrant Detector

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4722 ◽  
Author(s):  
Zhang ◽  
Guo ◽  
Zhang ◽  
Zhao
Keyword(s):  
Least Squares ◽  
Detection Accuracy ◽  
Moving Target ◽  
Positioning System ◽  
Improved Method ◽  
Laser Tracking ◽  
Least Squares Fitting ◽  
Position Detection ◽  
Operation Speed ◽  
Four Quadrant

For the laser tracking and positioning system of a moving target using a four-quadrant detector, the accuracy of laser spot position detection has a serious impact on the tracking performance of the system. For moving target tracking, the traditional spot position detection method of a four-quadrant detector cannot give better consideration to both detection accuracy and operation speed. In view of this, an improved method based on piecewise low-order polynomial least squares fitting and a Kalman filter is proposed. Firstly, the tracking and positioning mathematical model of the system is created, and the experimental device is established. Then, the shortcomings of traditional methods are analyzed, and the improved method and the real-time tracking and positioning algorithm of the system are studied. Finally, through the experiment, the system operation effects are compared and analyzed before and after the improvement. The experimental results of system dynamic tracking show that, the least squares fitting of the experimental data using a 5-segment and quadratic polynomial can achieve better results. By using the improved method, the maximum tracking distance of a moving object is increased from 12 m to more than 30 m. At a distance of 7.5 m, the maximum tracking speed can reach 2.11 m/s, and the root mean square error (RMSE) of the position is less than 4.59 mm. At 15.5 m, the maximum tracking speed is 2.04 m/s and the RMSE is less than 5.42 mm. Additionally, at 23.5 m, it is 1.13 m/s and 5.71 mm.

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