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Content-aware contrast ratio measure for images
Signal Processing: Image Communication, 2018Abstract In image fidelity assessment it is often necessary to quantify the level of visibility between a structure of interest or foreground and its surrounding background, i.e., the contrast ratio. Today, there is no standard procedure to measure the contrast ratio in digital images.
Benhur Ortiz Jaramillo +3 more
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Articulation: Brightness, Apparent Illumination, and Contrast Ratios
Perception, 2002Luminance edges in the environment can be due to regions that differ in reflectance or in illumination. In three experiments, we varied the spatial organization of 10 achromatic (simulated) surfaces so that some arrangements were consistent with an ecologically valid and parsimonious interpretation of 5 surfaces under two different illuminants.
James A, Schirillo, Steven K, Shevell
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Signal-to-noise ratio and contrast-to-noise ratio measurements for next generation tomosynthesis
Medical Imaging 2021: Physics of Medical Imaging, 2021It is standard for the x-ray source in conventional digital breast tomosynthesis (DBT) acquisitions to move strictly along the chest wall of the patient. A prototype, next-generation tomosynthesis (NGT) system has been developed that is capable of acquiring customized geometries with source motion parallel and perpendicular to the chest wall.
David A, Martin +5 more
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Acoustooptical device with extremely high contrast ratio
Applied Optics, 1983A double-path arrangement with two separate beams passing through the crystal of an AO modulator is proposed in order to significantly increase the static contrast ratio of the system. The different components of light leakage affecting the contrast ratio are considered theoretically. The experiments with a new AO arrangement are described.
A, Men, M, Rosenberg
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Improved contrast to tissue ratio at higher harmonics
Ultrasonics, 2002The challenge in ultrasound contrast imaging is a better discrimination between the perfused tissue and the contrast bubbles, which is usually expressed by contrast to tissue ratio (CTR). Imaging based on the second harmonic frequency showed a higher CTR than imaging at the fundamental frequency.
Bouakaz, A +3 more
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Contrast and Signal-to-Noise Ratio
1996In an MR image, information is contained in the variation across the image of one single parameter: the grey level, which is a proportional to the signal level at that position. This parameter, called contrast, is the result of three properties of the imaged tissue: the proton density, p; the spin-lattice relaxation time, T 1; and the spin-spin ...
Marinus T. Vlaardingerbroek +1 more
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Contrast Ratio Quantification During Visualization of Microvasculature
2018Visualization and monitoring of capillary loops in dermis and mucosa are of interest for a number of clinical applications, such as capillaroscopy, early cancer, or shock detection. For historical reasons, an unaided eye is still a primary aide to diagnostics in visual examinations for many medical specializations. However, the ability to make an early
G, Saiko, A, Douplik
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Contrast-to-noise ratio optimization for a prototype phase-contrast computed tomography scanner
Review of Scientific Instruments, 2015In the field of biomedical X-ray imaging, novel techniques, such as phase-contrast and dark-field imaging, have the potential to enhance the contrast and provide complementary structural information about a specimen. In this paper, a first prototype of a preclinical X-ray phase-contrast CT scanner based on a Talbot-Lau interferometer is characterized ...
Mark Müller +8 more
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Orthogonal Contrasts in Slope Ratio Investigations
Biometrics, 1959It is customary in the analysis of variance of balanced experimenlts to partition sums of squares into nmean squares corresponding with linear, quadratic, and other components of regression of response on the various independent variables. Undoubtedly this is a reasonable approach if the overall fornm of the regression line is the object of study, but ...
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