Chromacity
noun
\’krō-mə-sə-tē\
Chromacity is a
spectral
characteristic of
light based on a 2‑D
coordinate system (CIE
Yxy color model).
For more information
about chromacity,
see the ACPI
specification. The
sensor platform
definition for
chromacity is:
SENSOR_DATA_TYPE_LIGHT_CHROMACITYSome color spaces separate the three
dimensions of color into one luminance dimension and a pair of
chromaticity dimensions. For example, the chromaticity
coordinates are a and b in Lab color space, u
and v in Luv color space,
x and y in xyY space, etc. These pairs define
chromaticity vectors in a rectangular 2-space, unlike the polar
coordinates of hue angle and saturation that are used in
HSV color space.
On the other hand, some color spaces
such as RGB and
XYZ do not separate out chromaticity; chromaticity coordinates
such as r and g or x and y can be
calculated by an operation that normalizes out intensity.
The xyY space is a cross between the
CIE XYZ color space and its
normalized chromaticity coordinates xyz, such that the luminance
Y is preserved and augmented with just the required two
chromaticity dimensions.
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