نتایج جستجو برای: scatter

تعداد نتایج: 12375  

Journal: :Information Visualization 2010
Ming C. Hao Umeshwar Dayal Ratnesh K. Sharma Daniel A. Keim Halldór Janetzko

The scatter plot is a well-known method of visualizing pairs of two continuous variables. Scatter plots are intuitive and easy-to-use, but often have a high degree of overlap which may occlude a significant portion of the data. To analyze a dense non-uniform dataset, a recursive drill-down is required for detailed analysis. In this paper, we propose variable binned scatter plots to allow the vi...

Journal: :Medical physics 2013
A Sisniega W Zbijewski A Badal I S Kyprianou J W Stayman J J Vaquero J H Siewerdsen

PURPOSE The proliferation of cone-beam CT (CBCT) has created interest in performance optimization, with x-ray scatter identified among the main limitations to image quality. CBCT often contends with elevated scatter, but the wide variety of imaging geometry in different CBCT configurations suggests that not all configurations are affected to the same extent. Graphics processing unit (GPU) accel...

Introduction: Myocardial perfusion imaging is a nuclear medicine imaging method that is used to detect coronary artery diseases. One of the main sources of error in this imaging method is the detection of Compton scattered photons in the photopeak energy window used for data acquisition. This results in the degradation of the image contrast, and therefore decreases the...

1994
Fred Glover

We provide a tutorial survey of connections between genetic algorithms and scatter search that have useful implications for developing new methods for optimization problems. The links between these approaches are rooted in principles underlying mathematical relaxations, which became inherited and extended by scatter search. Hybrid methods incorporating elements of genetic algorithms and scatter...

2017
Ryan J. McGill

Within the professional literature, it is frequently suggested that interpretation of cognitive profile scatter may be useful for clinical and/or diagnostic decision-making. To wit, Hale and colleagues (2008) posit that cognitive scatter is a defining characteristic of learning disabilities and that individuals with learning disabilities may have higher levels of scatter than normal controls. T...

Journal: :Journal of radiological protection : official journal of the Society for Radiological Protection 2014
David John Platten

Existing data used to calculate the barrier transmission of scattered radiation from computed tomography (CT) are based on primary beam CT energy spectra. This study uses the EGSnrc Monte Carlo system and Epp user code to determine the energy spectra of CT scatter from four different primary CT beams passing through an ICRP 110 male reference phantom. Each scatter spectrum was used as a broad-b...

2007
Lynn Sheehan Mark Kozlowski Frank Rainer

The Laser Damage and Conditioning Group at LLNL is evaluating diagnostics which will help make damage testing more efficient and reduce the risk of damage during laser conditioning. The work to date has focused on photoacoustic and scattered light measurements on 1064-nm wavelength Hf@/Si02 multilayer mirror and polarizer coatings. Both the acoustic and scatter diagnostics have resolved 10 pm d...

2011
Angelica Svalkvist Gustaf Ullman Markus Håkansson David Dance Michael Sandborg Gudrun Alm Carlsson Magnus Båth

The primary aim of the present work was to analyze the effects of varying scatter-to-primary ratios on the appearance of simulated nodules in chest tomosynthesis section images. Monte Carlo simulations of the chest tomosynthesis system GE Definium 8000 VolumeRAD (GE Healthcare, Chalfont St. Giles, UK) were used to investigate the variation of scatter-to-primary ratios between different angular ...

Journal: :Nihon Hoshasen Gijutsu Gakkai zasshi 2006
Hideki Kato

The anti-scatter grid is generally used as a way of eliminating scattered radiation from X-ray photographs. This does not change even if the detector system changes from an analogue system to a digital system such as the flat-panel detector. We developed a new method that uses software to eliminate scatter components from digital X-ray images taken without the use of an anti-scatter grid. With ...

Journal: :Medical physics 1997
M S Westmore A Fenster I A Cunningham

A new special-purpose computed tomographic (CT) imaging system is described which produces images based on measurements of the low-angle (0-10 degrees) x-ray diffraction properties of an object. Low-angle scatter in the diagnostic x-ray energy range is dominated by coherent scatter, and the system uses first-generation CT geometry to acquire a diffraction pattern for each pencil beam. The patte...

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