colour.RGB_to_ICtCp#
- colour.RGB_to_ICtCp(RGB: ArrayLike, method: Literal['Dolby 2016', 'ITU-R BT.2100-1 HLG', 'ITU-R BT.2100-1 PQ', 'ITU-R BT.2100-2 HLG', 'ITU-R BT.2100-2 PQ'] | str = 'Dolby 2016', L_p: float = 10000) NDArrayFloat [source]#
Convert from ITU-R BT.2020 colourspace to \(IC_TC_P\) colour encoding.
- Parameters:
RGB (ArrayLike) – ITU-R BT.2020 colourspace array.
method (Literal['Dolby 2016', 'ITU-R BT.2100-1 HLG', 'ITU-R BT.2100-1 PQ', 'ITU-R BT.2100-2 HLG', 'ITU-R BT.2100-2 PQ'] | str) –
Computation method. Recommendation ITU-R BT.2100 defines multiple variants of the \(IC_TC_P\) colour encoding:
ITU-R BT.2100-1
SMPTE ST 2084:2014 inverse electro-optical transfer function (EOTF) and the \(IC_TC_P\) matrix from [Dolby16]: Dolby 2016, ITU-R BT.2100-1 PQ, ITU-R BT.2100-2 PQ methods.
Recommendation ITU-R BT.2100 Reference HLG opto-electrical transfer function (OETF) and the \(IC_TC_P\) matrix from [Dolby16]: ITU-R BT.2100-1 HLG method.
ITU-R BT.2100-2
SMPTE ST 2084:2014 inverse electro-optical transfer function (EOTF) and the \(IC_TC_P\) matrix from [Dolby16]: Dolby 2016, ITU-R BT.2100-1 PQ, ITU-R BT.2100-2 PQ methods.
Recommendation ITU-R BT.2100 Reference HLG opto-electrical transfer function (OETF) and a custom \(IC_TC_P\) matrix from [InternationalTUnion18]: ITU-R BT.2100-2 HLG method.
L_p (float) – Display peak luminance \(cd/m^2\) for SMPTE ST 2084:2014 non-linear encoding. This parameter should stay at its default \(10000 cd/m^2\) value for practical applications. It is exposed so that the definition can be used as a fitting function.
- Returns:
\(IC_TC_P\) colour encoding array.
- Return type:
Warning
The underlying SMPTE ST 2084:2014 transfer function is an absolute transfer function.
Notes
The ITU-R BT.2100-1 PQ and ITU-R BT.2100-2 PQ methods are aliases for the Dolby 2016 method.
The underlying SMPTE ST 2084:2014 transfer function is an absolute transfer function, thus the domain and range values for the Reference and 1 scales are only indicative that the data is not affected by scale transformations. The effective domain of SMPTE ST 2084:2014 inverse electro-optical transfer function (EOTF) is [0.0001, 10000].
Domain
Scale - Reference
Scale - 1
RGB
UN
UN
Range
Scale - Reference
Scale - 1
ICtCp
I
: [0, 1]CT
: [-1, 1]CP
: [-1, 1]I
: [0, 1]CT
: [-1, 1]CP
: [-1, 1]References
Examples
>>> RGB = np.array([0.45620519, 0.03081071, 0.04091952]) >>> RGB_to_ICtCp(RGB) array([ 0.0735136..., 0.0047525..., 0.0935159...]) >>> RGB_to_ICtCp(RGB, method="ITU-R BT.2100-2 HLG") array([ 0.6256789..., -0.0198449..., 0.3591125...])