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Relative luminance follows the photometric definition of luminance including spectral weighting for human vision, but while luminance is a measure of light in units such as /, relative luminance values are normalized as 0.0 to 1.0 (or 1 to 100), with 1.0 (or 100) being a theoretical perfect reflector of 100% reference white. [1]
Luminance (Y or L v,Ω) The radiance weighted by the effect of each wavelength on a typical human observer, measured in SI units in candela per square meter (cd/m 2). Often the term luminance is used for the relative luminance, Y/Y n, where Y n is the luminance of the reference white point. Luma (Y ′)
It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a standard observer. While luminance is a linear measurement of light, lightness is a linear prediction of the human perception of that light.
This means that for an ideal optical system, the luminance at the output is the same as the input luminance. For real, passive optical systems, the output luminance is at most equal to the input. As an example, if one uses a lens to form an image that is smaller than the source object, the luminous power is concentrated into a smaller area ...
RGB values of example colors with the same relative luminance as the lightest primary color (green) using BT. 709 primaries for ' (gamma correction) = 2.2 Luma is the weighted sum of gamma-compressed R′G′B′ components of a color video—the prime symbols ′ denote gamma compression .
Luminance. This section lists examples of luminances, measured in candelas per square metre and grouped by order of magnitude. Factor
where η is the relative luminance efficiency, and d is defined as positive on the temporal side of the pupil and negative on the nasal side of the pupil. [ 1 ] Measurements of the relative luminance efficiency are typically largest and symmetric about some distance ( d m ), which is typically ranges from -0.2 to -0.5 mm, away from the center ...
In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye.