Display Contrast
Contrast in visual perception is the difference in appearance of two or more parts of a field seen simultaneously or successively (hence: brightness contrast, lightness contrast, color contrast, simultaneous contrast, successive contrast, etc.).
Contrast in physics is a quantity intended to correlate with the perceived brightness contrast, usually defined by one of a number of formulae (see below) which involve e.g. the luminances of the stimuli considered, for example: ΔL/L near the luminance threshold (known as Weber contrast), or LH/LL for much higher luminances.
A contrast can also be due to differences of chromaticity specified by colorimetric characteristics (e.g. the color difference ΔE CIE 1976 UCS).
Visual information is always contained in some kind of visual contrast, thus contrast is an essential performance feature of electronic visual displays.
The contrast of electronic visual displays depends on the electrical driving (analog or digital input signal), on the ambient illumination and on the direction of observation (i.e. viewing direction).
In the field of electronic visual displays the following forms of contrast can be distinguished:
- luminance contrast,
- color contrast,
- full-screen contrast (time sequential),
- full-swing contrast (maximum and minimum luminance),
- static contrast (optical response settled),
- transient contrast (optical response not settled),
- dynamic contrast (technique for improving the sequential contrast of LCD-screens by backlight modulation)
- dark-room contrast (no ambient illumination),
- "ambient contrast" (short for: contrast in the presence of ambient illumination),
- concurrent contrast (dark and light areas presented at the same time, simultaneously),
- successive contrast (contrast between visual stimuli presented in sequence).
Read more about Display Contrast: Luminance Contrast, Color Contrast, Full-screen Contrast, Full-swing Contrast, Static Contrast, Transient Contrast, Dynamic Contrast, Dark-room Contrast, "Ambient Contrast", Concurrent Contrast, Successive Contrast, Methods of Measurement
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