colour.models.ootf_inverse_BT2100_HLG

colour.models.ootf_inverse_BT2100_HLG(F_D: Domain1, L_B: float = 0, L_W: float = 1000, gamma: float | None = None, method: Literal['ITU-R BT.2100-1', 'ITU-R BT.2100-2'] | str = 'ITU-R BT.2100-2') → Range1

Apply the Recommendation ITU-R BT.2100 Reference HLG inverse opto-optical transfer function (OOTF).

The inverse OOTF maps display linear light to relative scene linear light.

Parameters:

• F_D (Domain1) – Luminance \(F_D\) of a displayed linear component \(\{R_D, G_D, B_D\}\) or \(Y_D\) or \(I_D\), in \(cd/m^2\).

• L_B (float) – Display luminance for black \(L_B\) in \(cd/m^2\).

• L_W (float) – Nominal peak luminance \(L_W\) of the display in \(cd/m^2\) for achromatic pixels.

• gamma (float | None) – System gamma value, defaults to 1.2 at the nominal display peak luminance of \(1000 cd/m^2\).

• method (Literal['ITU-R BT.2100-1', 'ITU-R BT.2100-2'] | str) – Computation method.

Returns:

\(E\) denotes the signal for each colour component \(\{R_S, G_S, B_S\}\) proportional to scene linear light and scaled by camera exposure.

Return type:

numpy.ndarray

Notes

Domain	Scale - Reference	Scale - 1
F_D	1	1

Range	Scale - Reference	Scale - 1
E	1	1

References

[Bor17], [InternationalTUnion17], [InternationalTUnion18]

Examples

>>> ootf_inverse_BT2100_HLG(63.095734448019336)
np.float64(0.1000000...)
>>> ootf_inverse_BT2100_HLG(63.105103490674857, 0.01, method="ITU-R BT.2100-1")
...
np.float64(0.0999999...)