colour.polynomial_expansion¶
- colour.polynomial_expansion(a: ArrayLike, method: Union[Literal['Cheung 2004', 'Finlayson 2015', 'Vandermonde'], str] = 'Cheung 2004', **kwargs: Any) numpy.ndarray[source]¶
Perform polynomial expansion of given \(a\) array.
- Parameters
a (ArrayLike) – \(a\) array to expand.
method (Union[Literal['Cheung 2004', 'Finlayson 2015', 'Vandermonde'], str]) – Computation method.
degree – {
colour.characterisation.polynomial_expansion_Finlayson2015(),colour.characterisation.polynomial_expansion_Vandermonde()}, Expanded polynomial degree, must be one of [1, 2, 3, 4] forcolour.characterisation.polynomial_expansion_Finlayson2015()definition.root_polynomial_expansion – {
colour.characterisation.polynomial_expansion_Finlayson2015()}, Whether to use the root-polynomials set for the expansion.terms – {
colour.characterisation.matrix_augmented_Cheung2004()}, Number of terms of the expanded polynomial.kwargs (Any) –
- Returns
Expanded \(a\) array.
- Return type
References
[CWCR04], [FMH15], [WR04], [Wikipedia03f]
Examples
>>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> polynomial_expansion(RGB) array([ 0.1722481..., 0.0917066..., 0.0641693...]) >>> polynomial_expansion(RGB, 'Cheung 2004', terms=5) array([ 0.1722481..., 0.0917066..., 0.0641693..., 0.0010136..., 1...])