bundles / skimage 0.26.1rc0.dev0+git20260530.b607368ff / skimage / color / colorconv / xyz_tristimulus_values

function

`skimage.color.colorconv:xyz_tristimulus_values`

source: /dev/scikit-image/src/skimage/color/colorconv.py:565

Signature

def xyz_tristimulus_values(*, illuminant, observer, dtype = <class 'float'>)

Summary

Get the CIE XYZ tristimulus values.

Extended Summary

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].
dtype : dtype, optional: Output data type.

Returns

values : array: 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.

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")

✓

Aliases

skimage.color.xyz_tristimulus_values