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The CIE 1924 photopic V(λ) luminosity function, [cie 3] which is included in the CIE 1931 color-matching functions as the y (λ) function, has long been acknowledged to underestimate the contribution of the blue end of the spectrum to perceived luminance. There have been numerous attempts to improve the standard function, to make it more ...
A comparison between a typical normalized M cone's spectral sensitivity and the CIE 1931 luminosity function for a standard observer in photopic vision. In the CIE 1931 model, Y is the luminance, Z is quasi-equal to blue (of CIE RGB), and X is a mix of the three CIE RGB curves chosen to be nonnegative (see § Definition of the CIE XYZ color space).
Photopic (daytime-adapted, black curve) and scotopic (darkness-adapted, green curve) luminosity functions. The photopic includes the CIE 1931 standard (solid), the Judd-Vos 1978 modified data (dashed), and the Sharpe, Stockman, Jagla & Jägle 2005 data (dotted). The horizontal axis is wavelength in nm. Photometry is a branch of optics that ...
There are two luminous efficiency functions in common use. For everyday light levels, the photopic luminosity function best approximates the response of the human eye. For low light levels, the response of the human eye changes, and the scotopic curve applies. The photopic curve is the CIE standard curve used in the CIE 1931 color space.
Photopic vision is the vision of the eye under well-lit conditions (luminance levels from 10 to 10 8 cd/m 2). In humans and many other animals, photopic vision allows color perception , mediated by cone cells , and a significantly higher visual acuity and temporal resolution than available with scotopic vision .
The scotopic luminosity function is a standard function established by the Commission Internationale de l'Éclairage (CIE) and standardized in collaboration with the ISO. [ 11 ] The maximum scotopic efficacy is 1700 lm/W at 507 nm (compared with 683 lm/W at 555 nm for maximum photopic efficacy). [ 12 ]
CIE. Archived June 3, 2005, at the Wayback Machine. 1931 Standard Colorimetric Observer functions between 380 nm and 780 nm (at 5 nm intervals).. One of the first mathematically defined color spaces is the CIE XYZ color space (also known as CIE 1931 color space), created by the International Commission on Illumination in 1931.
The above development has the advantage of basing the new X F Y F Z F color matching functions on the physiologically-based LMS cone response functions. In addition, it offers a one-to-one relationship between the LMS chromaticity coordinates and the new X F Y F Z F chromaticity coordinates, which was not the case for the CIE 1931 color ...