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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 Chubb illusion is similar to another visual illusion, the contrast effect.The contrast effect is an illusion in which the perceived brightness or luminance of an identical central visual target form on a larger uniform background varies to the test subject depending on the ratio of the central form's luminance to that of its background. [4]
By contrast, black-and-white or gray-monochrome photography records only a single channel of luminance (brightness) and uses media capable only of showing shades of gray. In color photography, electronic sensors or light-sensitive chemicals record color information at the time of exposure .
The Luminosity mode is commonly used for image sharpening, because human vision is much more sensitive to fine-scale lightness contrast than color contrast. (See Contrast (vision) ) Few editors other than Photoshop implement this same color space for their analogs of these blend modes. [ 3 ]
The contrast ranges from black at the weakest intensity to white at the strongest. [1] Grayscale images are distinct from one-bit bi-tonal black-and-white images, which, in the context of computer imaging, are images with only two colors: black and white (also called bilevel or binary images). Grayscale images have many shades of gray in between.
[23] [24] The HDR display must have either a peak brightness of over 1000 cd/m 2 and a black level less than 0.05 cd/m 2 (a contrast ratio of at least 20,000:1) or a peak brightness of over 540 cd/m 2 and a black level less than 0.0005 cd/m 2 (a contrast ratio of at least 1,080,000:1).
Film negatives usually have less contrast, but a wider dynamic range, than the final printed positive images. The contrast typically increases when they are printed onto photographic paper. When negative film images are brought into the digital realm, their contrast may be adjusted at the time of scanning or, more usually, during subsequent ...
The operator can select other high-contrast spots within the image in an attempt to select one that is either on the target or very close to it. [2] Once a suitable target image has been selected, the seeker enters tracking mode. In this mode, the output from the camera is ignored except when it is scanning close to the original pickled location.