colour.colorimetry.lightness_Abebe2017

colour.colorimetry.lightness_Abebe2017(Y: ArrayLike, Y_n: ArrayLike | None = None, method: Literal['Michaelis-Menten', 'Stevens'] | str = 'Michaelis-Menten') → NDArrayFloat

Compute lightness \(L\) from the specified luminance \(Y\) using Abebe, Pouli, Larabi and Reinhard (2017) adaptive method for high-dynamic-range imaging according to Michaelis-Menten kinetics or Stevens’s Power Law.

Parameters:

• Y (ArrayLike) – Luminance \(Y\) in \(cd/m^2\).

• Y_n (ArrayLike | None) – Adapting luminance \(Y_n\) in \(cd/m^2\).

• method (Literal['Michaelis-Menten', 'Stevens'] | str) – Lightness \(L\) computation method.

Returns:

Lightness \(L\).

Return type:

numpy.ndarray

Notes

• Abebe, Pouli, Larabi and Reinhard (2017) method uses absolute luminance levels, thus the domain and range values for the Reference and 1 scales are only indicative that the data is not affected by scale transformations.

Domain	Scale - Reference	Scale - 1
Y	UN	UN
Y_n	UN	UN

Range	Scale - Reference	Scale - 1
L	UN	UN

References

[APLR17]

Examples

>>> lightness_Abebe2017(12.19722535)
np.float64(0.4869555...)
>>> lightness_Abebe2017(12.19722535, method="Stevens")
...
np.float64(0.4745447...)