We can therefore uniquely describe the emission of, say, an LED with the colour coordinates (0.65, 0.34). Because the coordinates were defined as the result of experiments on vision with several participants 5, 6, they represent a standardized observer, making the CIE standard device-invariant. No matter which coordinates one chooses, the CIE space contains all colours that an average person can see, but in the xy plane the spectral colours that can be described by a single wavelength form the outline of the CIE map, as illustrated in the figure, which also shows the loci of particular monochromatic wavelengths. Today it is common to use the x, y and z coordinates, which give the proportion of the X, Y and Z values within their sum. It was developed by Westwood Associates and published by Strategic Simulations, Inc. These relations were first defined in 1931, along with the XYZ standard itself, by the International Commission on Illumination (CIE) after serious debate and following recommendations of researchers 4 the exact definitions of the coordinates and their relations have been updated several times since. Eye of the Beholder is a computer game released in 1991. Unlike in the approach of mixing three primary colours and using the corresponding composition ratios to define the colour in question, the X, Y and Z coordinates in the CIE standard can be directly related to optical measurements (reflection, transmission and spectral radiance) using specific analytical expressions.
The most familiar example of such a trichromatic system is the RGB standard used in computer graphics, which uses experimentally determined averages of red, green and blue perception as its base colours 3 rather than the SLM wavelengths of the cones. What we see as colour is the combined response of cones, effectively mixing the colours within the response spectrum of the cones at a ratio defined by their spectral sensitivity.
2), respectively, but the exact wavelengths vary from person to person - and the cone types are often referred to as S, M and L for short, medium and long wavelength. Their sensitivities are centred around a blue, a green and a red wavelength - typically around 426 nm, 530 nm and 555 nm (ref. Humans have three different types of cones - the colour receptors in the retina - that detect different wavelength ranges. Since colour cannot be separated from vision, we also have to take into account our perception of colour, and the most obvious way to do this is by mimicking the physiology that lets us see colours in the first place.
0 kommentar(er)
