contrast


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contrast

1. (in painting) the effect of the juxtaposition of different colours, tones, etc.
2. 
a. (of a photographic emulsion) the degree of density measured against exposure used
b. the extent to which adjacent areas of an optical image, esp on a television screen or in a photographic negative or print, differ in brightness
3. Psychol the phenomenon that when two different but related stimuli are presented close together in space and/or time they are perceived as being more different than they really are

Contrast

A juxtaposition of dissimilar elements to show the differences of form or color, or to set in opposition in order to emphasize the differences.

Contrast

 

in psychology, the subjective exaggeration of the differences between perceived objects or between certain sectors of the visual field during their spatial (simultaneous contrast) or temporal (successive contrast) contiguity. Thus, when the color black is placed next to white it seems even blacker. Contrast may also be manifested in color change. For example, a gray square on a red background seems greenish blue; on a blue background it looks orange. The sharpest contrast of two colors is expressed at the boundary of the two areas (boundary contrast). The phenomenon of assimilation is the opposite of contrast. Contrast is widely used in various forms of art and literature.

REFERENCES

Vudvorts, R. Eksperimental’naia psikhologiia. Moscow, 1950.
Teplov, B. M. “Vzaimodeistvie odnovremennykh svetovykh oschchushchenii.” In Zritel’nye oshchushcheniia i vospriiatiia. Moscow-Leningrad, 1935.

contrast

[′kän‚trast]
(communications)
The degree of difference in tone between the lightest and darkest areas in a television or facsimile picture.
(computer science)
In optical character recognition, the difference in color, reflectance, or shading between two areas of a surface, for example,a character and its background.

contrast

The white level of a display screen. The contrast adjusts how bright the white is. See brightness and contrast ratio.
References in periodicals archive ?
Some of the major primary and secondary sources included in the report for the contrast media agents market are World Health Organization, Dubai Health Authority, Canadian Cancer Society, Canadian Agency for Drugs and Technologies in Health, American Cancer Society, CBI Ministry of Foreign Affairs, Cancer Organization Soutien, Global Burden of Diseases, Entabeni Pretoria, South Africa and others.
More than 30m imaging procedures are performed each year in the US Iodinated contrast agents represent more than 60 percent of all X-ray imaging agents sold with an annual US market of approximately USD 1.5bn.
The use of radio contrast media has increased greatly from the past decades for diagnostic radiography and interventional procedures and it is estimated that approximately 60 million people in the world are administered radio contrast medium each year1.
This contrast agent distributes freely and does not bind to the plasma proteins making it dialyzable.
Low-osmolar barium sulfate is better tolerated in the bronchial tree than high-osmolar Gastrografin although the severity of pulmonary damage also correlates with the amount aspirated and contrast density.
And also patients who requiring left ventriculography, total contrast agent volume exceeding 60 cc, difficulty to engage coronary ostium by diagnostic catheters or exchanging from radial route to femoral route, and failure of radial artery cannulation during CA were excluded the study.
Since each kV level is strictly related to the vascular attenuation achievable with a given dose of contrast media, the decision regarding the optimal kV level for each patient is of paramount importance, not only to reduce the radiation exposure, but also to also lower the amount of injected contrast media.
Complete stagnation of contrast radiography below the base of teats were noticed in right and left fore quarter and minimal passage of contrast agent to caudal aspect of right and left hind quarter were noticed.
The needs to reduce both the radiation dose and contrast dose to children in CT are urgent because of their sensitivity to radiation damage and the side effects of contrast.[sup][10],[11],[21] However, there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations.
Conclusion: Increasing age, small pupil diameter, hyperopia, and photopic conditions were associated with lower contrast sensitivity in healthy individuals.
The image quality and diagnostic value of magnetic resonance imaging (MRI) of human tissues are primarily determined by the signal-to-noise ratio (SNR) and the tissue contrast.1,2 The contrast-to-noise (CNR) is the most critical factor affecting the image quality as it directly determines the eye's ability to distinguish areas of a high signal from areas of low signal.3,4
The global contrast media injectors market report provides market size estimates (Revenue USD million - 2013 to 2020) for key market segments based on product type (CT, MRI, and vascular injectors), its applications (cardiology, neurology, oncology, etc.), and forecasts growth trends (CAGR% - 2016 to 2020).