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Contrast ratio. The contrast ratio ( CR) is a property of a display system, defined as the ratio of the luminance of the brightest shade (white) to that of the darkest shade (black) that the system is capable of producing. A high contrast ratio is a desired aspect of any display. It has similarities with dynamic range .
The maximum contrast of an image is termed the contrast ratio or dynamic range. In images where the contrast ratio approaches the maximum possible for the medium, there is a conservation of contrast. In such cases, increasing contrast in certain parts of the image will necessarily result in a decrease in contrast elsewhere.
The "luminance contrast" is the ratio between the higher luminance, L H, and the lower luminance, L L, that define the feature to be detected.This ratio, often called contrast ratio, CR, (actually being a luminance ratio), is often used for high luminances and for specification of the contrast of electronic visual display devices.
For the majority of images it will consume 60–80% of the power of an LCD. OLED displays use 40% of the power of an LCD displaying an image that is primarily black as they lack the need for a backlight, [ 40] while OLED can use more than three times as much power to display a mostly white image compared to an LCD. [ 41]
A contrast is defined as the sum of each group mean multiplied by a coefficient for each group (i.e., a signed number, c j ). [ 10] In equation form, , where L is the weighted sum of group means, the c j coefficients represent the assigned weights of the means (these must sum to 0 for orthogonal contrasts), and j represents the group means. [ 8]
Contrast-to-noise ratio ( CNR) [ 1] is a measure used to determine image quality. CNR is similar to the metric signal-to-noise ratio (SNR), but subtracts a term before taking the ratio. This is important when there is a significant bias in an image, such as from haze. [ 2] As can be seen in the picture at right, the intensity is rather high ...
Contrast resolution is the ability to distinguish between differences in intensity in an image. [ 1] The measure is used in medical imaging to quantify the quality of acquired images. It is a difficult quantity to define because it depends on the human observer as much as the quality of the actual image. For example, the size of a feature ...
The sections below describe the theoretical estimates of resolution, but the real values may differ. The results below are based on mathematical models of Airy discs, which assumes an adequate level of contrast. In low-contrast systems, the resolution may be much lower than predicted by the theory outlined below.