In 1976, the CIE defined a three-dimensional color space that is perceptually more uniform than the CIE XYZ color space (International Commission on Illumination 1996). The... [Pg.89]

Figure 2.9. Three-dimensional color space (a) and color solid (b) of hue, lightness, and saturation (Minolta, 1993). |

A color can be numerically defined as a point in a three-dimensional color space. In the past, a vast number of color spaces, optimized for different applications have been developed. The most physical of these is the CIE-Yxy space, where all colors lie within a plane resembling a shoe sole. An arbitrary point B within that plane is defined by the Cartesian coordinates x and y, where the redness increases with x, and the greenness increases with y. The lightness, Y, is perpendicular to x and y out of the plane. An alternative... [Pg.33]

D Zmura and Lennie assume that red-green as well as blue-yellow color opponent cells are used to arrive at stable hue descriptors. They represent the chromatic sensitivity of a cell using a three-dimensional chromaticity space as shown in Figure 8.10. The white point is denoted by W. The white point describes the steady state of adaptation of the cell. The vector C represents the most effective choice of chromatic contrast, which will activate the cell. The preferred hue of the cell can be found by projecting the vector C onto... [Pg.204]

three-dimensional space that follows the opponent color system with +a as red, —a as green, +5 as yellow, and — b as blue. CIELAB is closely related to the older Adams-Nickerson, modified Adams-Nickerson, and other spaces of the Y,a,b type, which it replaced (1,3). [Pg.415]

In the CIELAB and CIELUV color spaces, the difference between a batch sample and a reference standard designated with a subscript s, can be designated by its components, eg, AAL = L — L. The three-dimensional total color differences are given by EucHdian geometry as the 1976 CIE lYa b and 1976 CIE lYu Y color difference formulas ... [Pg.415]

The HunterLab system (1958) was the hrst to use the opponent color theory stating that the red, green, and blue cone responses are re-mixed into opponent coders as they move up the optic nerve to the brain.Based on that theory, the HunterLab color space is three-dimensional and rectangular (see Figure 1.6). [Pg.19]

Ultramarines are three-dimensional cage-like structures. They differ from feldspars and zeolites because of the large spaces within the structures that can contain cations and anions but not water, illustrating a natural buckeyball-like structure and cavity, and a diversity of environment between the internal and external cages. Ultramarines can act as ion-exchangers for both anions and cations. The blue color of ultramarines is due to the presence of the ion although a yellow ion S2 also exists in the same structure. [Pg.389]

In the work with cottonseed flours, we used the Hunterlab color meter D25D2A and expressed these measurements as Hunter L, a, b color values. These are coordinates of the three-dimensional opponent-color space shown in Figure 2. The L value measures lightness, or the amount of light reflected or transmitted by the object. The a and b values are the chromaticity coordinates from which information about hue and saturation can be obtained. The a value measures redness when plus and greenness when minus. The b value measures yellowness when plus and blueness when minus. [Pg.23]

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