skimage2.color.xyz_tristimulus_values#
- skimage2.color.xyz_tristimulus_values(*, illuminant, observer, dtype=<class 'float'>)[source]#
Get the CIE XYZ tristimulus values.
Given an illuminant and observer, this function returns the CIE XYZ tristimulus values [2] scaled such that \(Y = 1\).
- Parameters:
- illuminant{“A”, “B”, “C”, “D50”, “D55”, “D65”, “D75”, “E”}
The name of the illuminant (the function is NOT case sensitive).
- observer{“2”, “10”, “R”}
One of: 2-degree observer, 10-degree observer, or ‘R’ observer as in R function
grDevices::convertColor[3].- dtypedtype, optional
Output data type.
- Returns:
- valuesarray
Array with 3 elements \(X, Y, Z\) containing the CIE XYZ tristimulus values of the given illuminant.
- Raises:
- ValueError
If either the illuminant or the observer angle are not supported or unknown.
Notes
The CIE XYZ tristimulus values are calculated from \(x, y\) [1], using the formula
\[X = x / y\]\[Y = 1\]\[Z = (1 - x - y) / y\]The only exception is the illuminant “D65” with aperture angle 2° for backward-compatibility reasons.
References
Examples
Get the CIE XYZ tristimulus values for a “D65” illuminant for a 10 degree field of view
>>> xyz_tristimulus_values(illuminant="D65", observer="10") array([0.94809668, 1. , 1.07305136])
