Source code for colour.characterisation.correction

"""
Colour Correction
=================

Defines various objects for colour correction, like colour matching two images:

-   :func:`colour.characterisation.matrix_augmented_Cheung2004` : Polynomial
    expansion using *Cheung, Westland, Connah and Ripamonti (2004)* method.
-   :func:`colour.characterisation.polynomial_expansion_Finlayson2015` :
    Polynomial expansion using *Finlayson, MacKiewicz and Hurlbert (2015)*
    method.
-   :func:`colour.characterisation.polynomial_expansion_Vandermonde` :
    Polynomial expansion using *Vandermonde* method.
-   :attr:`colour.POLYNOMIAL_EXPANSION_METHODS`: Supported polynomial expansion
    methods.
-   :func:`colour.polynomial_expansion`: Polynomial expansion of given
    :math:`a` array.
-   :func:`colour.characterisation.matrix_colour_correction_Cheung2004` :
    Colour correction matrix computation using *Cheung et al. (2004)* method.
-   :func:`colour.characterisation.matrix_colour_correction_Finlayson2015` :
    Colour correction matrix computation using *Finlayson et al. (2015)*
    method.
-   :func:`colour.characterisation.matrix_colour_correction_Vandermonde`
    Colour correction matrix computation using *Vandermonde* method.
-   :attr:`colour.MATRIX_COLOUR_CORRECTION_METHODS`: Supported colour
    correction matrix methods.
-   :func:`colour.matrix_colour_correction`: Colour correction matrix
    computation from given :math:`M_T` colour array to :math:`M_R` colour
    array.
-   :func:`colour.characterisation.colour_correction_Cheung2004` :
    Colour correction using *Cheung et al. (2004)* method.
-   :func:`colour.characterisation.colour_correction_Finlayson2015` :
    Colour correction using *Finlayson et al. (2015)* method.
-   :func:`colour.characterisation.colour_correction_Vandermonde` :
    Colour correction using *Vandermonde* method.
-   :attr:`colour.COLOUR_CORRECTION_METHODS`: Supported colour correction
    methods.
-   :func:`colour.colour_correction`: Colour correction of given *RGB*
    colourspace array using the colour correction matrix from given
    :math:`M_T` colour array to :math:`M_R` colour array.

References
----------
-   :cite:`Cheung2004` : Cheung, V., Westland, S., Connah, D., & Ripamonti, C.
    (2004). A comparative study of the characterisation of colour cameras by
    means of neural networks and polynomial transforms. Coloration Technology,
    120(1), 19-25. doi:10.1111/j.1478-4408.2004.tb00201.x
-   :cite:`Finlayson2015` : Finlayson, G. D., MacKiewicz, M., & Hurlbert, A.
    (2015). Color Correction Using Root-Polynomial Regression. IEEE
    Transactions on Image Processing, 24(5), 1460-1470.
    doi:10.1109/TIP.2015.2405336
-   :cite:`Westland2004` : Westland, S., & Ripamonti, C. (2004). Table 8.2. In
    Computational Colour Science Using MATLAB (1st ed., p. 137). John Wiley &
    Sons, Ltd. doi:10.1002/0470020326
-   :cite:`Wikipedia2003e` : Wikipedia. (2003). Vandermonde matrix. Retrieved
    May 2, 2018, from https://en.wikipedia.org/wiki/Vandermonde_matrix
"""

from __future__ import annotations

import numpy as np

from colour.algebra import least_square_mapping_MoorePenrose, spow
from colour.hints import (
    ArrayLike,
    Any,
    Boolean,
    Integer,
    Literal,
    NDArray,
    Union,
)
from colour.utilities import (
    CanonicalMapping,
    as_float_array,
    as_int,
    closest,
    filter_kwargs,
    ones,
    tsplit,
    tstack,
    validate_method,
)

__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 Colour Developers"
__license__ = "New BSD License - https://opensource.org/licenses/BSD-3-Clause"
__maintainer__ = "Colour Developers"
__email__ = "colour-developers@colour-science.org"
__status__ = "Production"

__all__ = [
    "matrix_augmented_Cheung2004",
    "polynomial_expansion_Finlayson2015",
    "polynomial_expansion_Vandermonde",
    "POLYNOMIAL_EXPANSION_METHODS",
    "polynomial_expansion",
    "matrix_colour_correction_Cheung2004",
    "matrix_colour_correction_Finlayson2015",
    "matrix_colour_correction_Vandermonde",
    "MATRIX_COLOUR_CORRECTION_METHODS",
    "matrix_colour_correction",
    "colour_correction_Cheung2004",
    "colour_correction_Finlayson2015",
    "colour_correction_Vandermonde",
    "COLOUR_CORRECTION_METHODS",
    "colour_correction",
]


[docs]def matrix_augmented_Cheung2004( RGB: ArrayLike, terms: Literal[3, 5, 7, 8, 10, 11, 14, 16, 17, 19, 20, 22] = 3, ) -> NDArray: """ Perform polynomial expansion of given *RGB* colourspace array using *Cheung et al. (2004)* method. Parameters ---------- RGB *RGB* colourspace array to expand. terms Number of terms of the expanded polynomial. Returns ------- :class:`numpy.ndarray` Expanded *RGB* colourspace array. Notes ----- - This definition combines the augmented matrices given in :cite:`Cheung2004` and :cite:`Westland2004`. References ---------- :cite:`Cheung2004`, :cite:`Westland2004` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> matrix_augmented_Cheung2004(RGB, terms=5) # doctest: +ELLIPSIS array([ 0.1722481..., 0.0917066..., 0.0641693..., 0.0010136..., 1...]) """ RGB = as_float_array(RGB) R, G, B = tsplit(RGB) tail = ones(R.shape) existing_terms = np.array([3, 5, 7, 8, 10, 11, 14, 16, 17, 19, 20, 22]) closest_terms = as_int(closest(existing_terms, terms)) if closest_terms != terms: raise ValueError( f'"Cheung et al. (2004)" method does not define an augmented ' f"matrix with {terms} terms, closest augmented matrix has " f"{closest_terms} terms!" ) if terms == 3: return RGB elif terms == 5: return tstack( [ R, G, B, R * G * B, tail, ] ) elif terms == 7: return tstack( [ R, G, B, R * G, R * B, G * B, tail, ] ) elif terms == 8: return tstack( [ R, G, B, R * G, R * B, G * B, R * G * B, tail, ] ) elif terms == 10: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, tail, ] ) elif terms == 11: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, tail, ] ) elif terms == 14: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, R**3, G**3, B**3, tail, ] ) elif terms == 16: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, R**2 * G, G**2 * B, B**2 * R, R**3, G**3, B**3, ] ) elif terms == 17: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, R**2 * G, G**2 * B, B**2 * R, R**3, G**3, B**3, tail, ] ) elif terms == 19: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, R**2 * G, G**2 * B, B**2 * R, R**2 * B, G**2 * R, B**2 * G, R**3, G**3, B**3, ] ) elif terms == 20: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, R**2 * G, G**2 * B, B**2 * R, R**2 * B, G**2 * R, B**2 * G, R**3, G**3, B**3, tail, ] ) elif terms == 22: return tstack( [ R, G, B, R * G, R * B, G * B, R**2, G**2, B**2, R * G * B, R**2 * G, G**2 * B, B**2 * R, R**2 * B, G**2 * R, B**2 * G, R**3, G**3, B**3, R**2 * G * B, R * G**2 * B, R * G * B**2, ] )
[docs]def polynomial_expansion_Finlayson2015( RGB: ArrayLike, degree: Literal[1, 2, 3, 4] = 1, root_polynomial_expansion: Boolean = True, ) -> NDArray: """ Perform polynomial expansion of given *RGB* colourspace array using *Finlayson et al. (2015)* method. Parameters ---------- RGB *RGB* colourspace array to expand. degree Expanded polynomial degree. root_polynomial_expansion Whether to use the root-polynomials set for the expansion. Returns ------- :class:`numpy.ndarray` Expanded *RGB* colourspace array. References ---------- :cite:`Finlayson2015` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> polynomial_expansion_Finlayson2015(RGB, degree=2) # doctest: +ELLIPSIS array([ 0.1722481..., 0.0917066..., 0.0641693..., 0.1256832..., \ 0.0767121..., 0.1051335...]) """ RGB = as_float_array(RGB) R, G, B = tsplit(RGB) # TODO: Generalise polynomial expansion. existing_degrees = np.array([1, 2, 3, 4]) closest_degree = as_int(closest(existing_degrees, degree)) if closest_degree != degree: raise ValueError( f'"Finlayson et al. (2015)" method does not define a polynomial ' f"expansion for {degree} degree, closest polynomial expansion is " f"{closest_degree} degree!" ) if degree == 1: return RGB elif degree == 2: if root_polynomial_expansion: return tstack( [ R, G, B, spow(R * G, 1 / 2), spow(G * B, 1 / 2), spow(R * B, 1 / 2), ] ) else: return tstack( [ R, G, B, R**2, G**2, B**2, R * G, G * B, R * B, ] ) elif degree == 3: if root_polynomial_expansion: return tstack( [ R, G, B, spow(R * G, 1 / 2), spow(G * B, 1 / 2), spow(R * B, 1 / 2), spow(R * G**2, 1 / 3), spow(G * B**2, 1 / 3), spow(R * B**2, 1 / 3), spow(G * R**2, 1 / 3), spow(B * G**2, 1 / 3), spow(B * R**2, 1 / 3), spow(R * G * B, 1 / 3), ] ) else: return tstack( [ R, G, B, R**2, G**2, B**2, R * G, G * B, R * B, R**3, G**3, B**3, R * G**2, G * B**2, R * B**2, G * R**2, B * G**2, B * R**2, R * G * B, ] ) elif degree == 4: if root_polynomial_expansion: return tstack( [ R, G, B, spow(R * G, 1 / 2), spow(G * B, 1 / 2), spow(R * B, 1 / 2), spow(R * G**2, 1 / 3), spow(G * B**2, 1 / 3), spow(R * B**2, 1 / 3), spow(G * R**2, 1 / 3), spow(B * G**2, 1 / 3), spow(B * R**2, 1 / 3), spow(R * G * B, 1 / 3), spow(R**3 * G, 1 / 4), spow(R**3 * B, 1 / 4), spow(G**3 * R, 1 / 4), spow(G**3 * B, 1 / 4), spow(B**3 * R, 1 / 4), spow(B**3 * G, 1 / 4), spow(R**2 * G * B, 1 / 4), spow(G**2 * R * B, 1 / 4), spow(B**2 * R * G, 1 / 4), ] ) else: return tstack( [ R, G, B, R**2, G**2, B**2, R * G, G * B, R * B, R**3, G**3, B**3, R * G**2, G * B**2, R * B**2, G * R**2, B * G**2, B * R**2, R * G * B, R**4, G**4, B**4, R**3 * G, R**3 * B, G**3 * R, G**3 * B, B**3 * R, B**3 * G, R**2 * G**2, G**2 * B**2, R**2 * B**2, R**2 * G * B, G**2 * R * B, B**2 * R * G, ] )
[docs]def polynomial_expansion_Vandermonde( a: ArrayLike, degree: Integer = 1 ) -> NDArray: """ Perform polynomial expansion of given :math:`a` array using *Vandermonde* method. Parameters ---------- a :math:`a` array to expand. degree Expanded polynomial degree. Returns ------- :class:`numpy.ndarray` Expanded :math:`a` array. References ---------- :cite:`Wikipedia2003e` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> polynomial_expansion_Vandermonde(RGB) # doctest: +ELLIPSIS array([ 0.1722481 , 0.0917066 , 0.06416938, 1. ]) """ a = as_float_array(a) a_e = np.transpose(np.vander(np.ravel(a), int(degree) + 1)) a_e = np.hstack(list(np.reshape(a_e, (a_e.shape[0], -1, 3)))) return np.squeeze(a_e[:, 0 : a_e.shape[-1] - a.shape[-1] + 1])
POLYNOMIAL_EXPANSION_METHODS: CanonicalMapping = CanonicalMapping( { "Cheung 2004": matrix_augmented_Cheung2004, "Finlayson 2015": polynomial_expansion_Finlayson2015, "Vandermonde": polynomial_expansion_Vandermonde, } ) POLYNOMIAL_EXPANSION_METHODS.__doc__ = """ Supported polynomial expansion methods. References ---------- :cite:`Cheung2004`, :cite:`Finlayson2015`, :cite:`Westland2004`, :cite:`Wikipedia2003e` """
[docs]def polynomial_expansion( a: ArrayLike, method: Union[ Literal["Cheung 2004", "Finlayson 2015", "Vandermonde"], str ] = "Cheung 2004", **kwargs: Any, ) -> NDArray: """ Perform polynomial expansion of given :math:`a` array. Parameters ---------- a :math:`a` array to expand. method Computation method. Other Parameters ---------------- degree {:func:`colour.characterisation.polynomial_expansion_Finlayson2015`, :func:`colour.characterisation.polynomial_expansion_Vandermonde`}, Expanded polynomial degree, must be one of *[1, 2, 3, 4]* for :func:`colour.characterisation.polynomial_expansion_Finlayson2015` definition. root_polynomial_expansion {:func:`colour.characterisation.polynomial_expansion_Finlayson2015`}, Whether to use the root-polynomials set for the expansion. terms {:func:`colour.characterisation.matrix_augmented_Cheung2004`}, Number of terms of the expanded polynomial. Returns ------- :class:`numpy.ndarray` Expanded :math:`a` array. References ---------- :cite:`Cheung2004`, :cite:`Finlayson2015`, :cite:`Westland2004`, :cite:`Wikipedia2003e` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> polynomial_expansion(RGB) # doctest: +ELLIPSIS array([ 0.1722481..., 0.0917066..., 0.0641693...]) >>> polynomial_expansion(RGB, 'Cheung 2004', terms=5) # doctest: +ELLIPSIS array([ 0.1722481..., 0.0917066..., 0.0641693..., 0.0010136..., 1...]) """ method = validate_method(method, POLYNOMIAL_EXPANSION_METHODS) function = POLYNOMIAL_EXPANSION_METHODS[method] return function(a, **filter_kwargs(function, **kwargs))
[docs]def matrix_colour_correction_Cheung2004( M_T: ArrayLike, M_R: ArrayLike, terms: Literal[3, 5, 7, 8, 10, 11, 14, 16, 17, 19, 20, 22] = 3, ) -> NDArray: """ Compute a colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array using *Cheung et al. (2004)* method. Parameters ---------- M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. terms Number of terms of the expanded polynomial. Returns ------- :class:`numpy.ndarray` Colour correction matrix. References ---------- :cite:`Cheung2004`, :cite:`Westland2004` Examples -------- >>> prng = np.random.RandomState(2) >>> M_T = prng.random_sample((24, 3)) >>> M_R = M_T + (prng.random_sample((24, 3)) - 0.5) * 0.5 >>> matrix_colour_correction_Cheung2004(M_T, M_R) # doctest: +ELLIPSIS array([[ 1.0526376..., 0.1378078..., -0.2276339...], [ 0.0739584..., 1.0293994..., -0.1060115...], [ 0.0572550..., -0.2052633..., 1.1015194...]]) """ return least_square_mapping_MoorePenrose( matrix_augmented_Cheung2004(M_T, terms), M_R )
[docs]def matrix_colour_correction_Finlayson2015( M_T: ArrayLike, M_R: ArrayLike, degree: Literal[1, 2, 3, 4] = 1, root_polynomial_expansion: Boolean = True, ) -> NDArray: """ Compute a colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array using *Finlayson et al. (2015)* method. Parameters ---------- M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. degree Expanded polynomial degree. root_polynomial_expansion Whether to use the root-polynomials set for the expansion. Returns ------- :class:`numpy.ndarray` Colour correction matrix. References ---------- :cite:`Finlayson2015` Examples -------- >>> prng = np.random.RandomState(2) >>> M_T = prng.random_sample((24, 3)) >>> M_R = M_T + (prng.random_sample((24, 3)) - 0.5) * 0.5 >>> matrix_colour_correction_Finlayson2015(M_T, M_R) # doctest: +ELLIPSIS array([[ 1.0526376..., 0.1378078..., -0.2276339...], [ 0.0739584..., 1.0293994..., -0.1060115...], [ 0.0572550..., -0.2052633..., 1.1015194...]]) """ return least_square_mapping_MoorePenrose( polynomial_expansion_Finlayson2015( M_T, degree, root_polynomial_expansion ), M_R, )
[docs]def matrix_colour_correction_Vandermonde( M_T: ArrayLike, M_R: ArrayLike, degree: Integer = 1 ) -> NDArray: """ Compute a colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array using *Vandermonde* method. Parameters ---------- M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. degree Expanded polynomial degree. Returns ------- :class:`numpy.ndarray` Colour correction matrix. References ---------- :cite:`Wikipedia2003e` Examples -------- >>> prng = np.random.RandomState(2) >>> M_T = prng.random_sample((24, 3)) >>> M_R = M_T + (prng.random_sample((24, 3)) - 0.5) * 0.5 >>> matrix_colour_correction_Vandermonde(M_T, M_R) # doctest: +ELLIPSIS array([[ 1.0300256..., 0.1141770..., -0.2621816..., 0.0418022...], [ 0.0670209..., 1.0221494..., -0.1166108..., 0.0128250...], [ 0.0744612..., -0.1872819..., 1.1278078..., -0.0318085...]]) """ return least_square_mapping_MoorePenrose( polynomial_expansion_Vandermonde(M_T, degree), M_R )
MATRIX_COLOUR_CORRECTION_METHODS: CanonicalMapping = CanonicalMapping( { "Cheung 2004": matrix_colour_correction_Cheung2004, "Finlayson 2015": matrix_colour_correction_Finlayson2015, "Vandermonde": matrix_colour_correction_Vandermonde, } ) MATRIX_COLOUR_CORRECTION_METHODS.__doc__ = """ Supported colour correction matrix methods. References ---------- :cite:`Cheung2004`, :cite:`Finlayson2015`, :cite:`Westland2004`, :cite:`Wikipedia2003e` """
[docs]def matrix_colour_correction( M_T: ArrayLike, M_R: ArrayLike, method: Union[ Literal["Cheung 2004", "Finlayson 2015", "Vandermonde"], str ] = "Cheung 2004", **kwargs: Any, ) -> NDArray: """ Compute a colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array. The resulting colour correction matrix is computed using multiple linear or polynomial regression using given method. The purpose of that object is for example the matching of two *ColorChecker* colour rendition charts together. Parameters ---------- M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. method Computation method. Other Parameters ---------------- degree {:func:`colour.characterisation.polynomial_expansion_Finlayson2015`, :func:`colour.characterisation.polynomial_expansion_Vandermonde`}, Expanded polynomial degree, must be one of *[1, 2, 3, 4]* for :func:`colour.characterisation.polynomial_expansion_Finlayson2015` definition. root_polynomial_expansion {:func:`colour.characterisation.polynomial_expansion_Finlayson2015`}, Whether to use the root-polynomials set for the expansion. terms {:func:`colour.characterisation.matrix_augmented_Cheung2004`}, Number of terms of the expanded polynomial. Returns ------- :class:`numpy.ndarray` Colour correction matrix. References ---------- :cite:`Cheung2004`, :cite:`Finlayson2015`, :cite:`Westland2004`, :cite:`Wikipedia2003e` Examples -------- >>> M_T = np.array( ... [[0.17224810, 0.09170660, 0.06416938], ... [0.49189645, 0.27802050, 0.21923399], ... [0.10999751, 0.18658946, 0.29938611], ... [0.11666120, 0.14327905, 0.05713804], ... [0.18988879, 0.18227649, 0.36056247], ... [0.12501329, 0.42223442, 0.37027445], ... [0.64785606, 0.22396782, 0.03365194], ... [0.06761093, 0.11076896, 0.39779139], ... [0.49101797, 0.09448929, 0.11623839], ... [0.11622386, 0.04425753, 0.14469986], ... [0.36867946, 0.44545230, 0.06028681], ... [0.61632937, 0.32323906, 0.02437089], ... [0.03016472, 0.06153243, 0.29014596], ... [0.11103655, 0.30553067, 0.08149137], ... [0.41162190, 0.05816656, 0.04845934], ... [0.73339206, 0.53075188, 0.02475212], ... [0.47347718, 0.08834792, 0.30310315], ... [0.00000000, 0.25187016, 0.35062450], ... [0.76809639, 0.78486240, 0.77808297], ... [0.53822392, 0.54307997, 0.54710883], ... [0.35458526, 0.35318419, 0.35524431], ... [0.17976704, 0.18000531, 0.17991488], ... [0.09351417, 0.09510603, 0.09675027], ... [0.03405071, 0.03295077, 0.03702047]] ... ) >>> M_R = np.array( ... [[0.15579559, 0.09715755, 0.07514556], ... [0.39113140, 0.25943419, 0.21266708], ... [0.12824821, 0.18463570, 0.31508023], ... [0.12028974, 0.13455659, 0.07408400], ... [0.19368988, 0.21158946, 0.37955964], ... [0.19957425, 0.36085439, 0.40678123], ... [0.48896605, 0.20691688, 0.05816533], ... [0.09775522, 0.16710693, 0.47147724], ... [0.39358649, 0.12233400, 0.10526425], ... [0.10780332, 0.07258529, 0.16151473], ... [0.27502671, 0.34705454, 0.09728099], ... [0.43980441, 0.26880559, 0.05430533], ... [0.05887212, 0.11126272, 0.38552469], ... [0.12705825, 0.25787860, 0.13566464], ... [0.35612929, 0.07933258, 0.05118732], ... [0.48131976, 0.42082843, 0.07120612], ... [0.34665585, 0.15170714, 0.24969804], ... [0.08261116, 0.24588716, 0.48707733], ... [0.66054904, 0.65941137, 0.66376412], ... [0.48051509, 0.47870296, 0.48230082], ... [0.33045354, 0.32904184, 0.33228886], ... [0.18001305, 0.17978567, 0.18004416], ... [0.10283975, 0.10424680, 0.10384975], ... [0.04742204, 0.04772203, 0.04914226]] ... ) >>> matrix_colour_correction(M_T, M_R) # doctest: +ELLIPSIS array([[ 0.6982266..., 0.0307162..., 0.1621042...], [ 0.0689349..., 0.6757961..., 0.1643038...], [-0.0631495..., 0.0921247..., 0.9713415...]]) """ method = validate_method(method, MATRIX_COLOUR_CORRECTION_METHODS) function = MATRIX_COLOUR_CORRECTION_METHODS[method] return function(M_T, M_R, **filter_kwargs(function, **kwargs))
[docs]def colour_correction_Cheung2004( RGB: ArrayLike, M_T: ArrayLike, M_R: ArrayLike, terms: Literal[3, 5, 7, 8, 10, 11, 14, 16, 17, 19, 20, 22] = 3, ) -> NDArray: """ Perform colour correction of given *RGB* colourspace array using the colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array using *Cheung et al. (2004)* method. Parameters ---------- RGB *RGB* colourspace array to colour correct. M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. terms Number of terms of the expanded polynomial. Returns ------- :class:`numpy.ndarray` Colour corrected *RGB* colourspace array. References ---------- :cite:`Cheung2004`, :cite:`Westland2004` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> prng = np.random.RandomState(2) >>> M_T = prng.random_sample((24, 3)) >>> M_R = M_T + (prng.random_sample((24, 3)) - 0.5) * 0.5 >>> colour_correction_Cheung2004(RGB, M_T, M_R) # doctest: +ELLIPSIS array([ 0.1793456..., 0.1003392..., 0.0617218...]) """ RGB = as_float_array(RGB) shape = RGB.shape RGB = np.reshape(RGB, (-1, 3)) RGB_e = matrix_augmented_Cheung2004(RGB, terms) CCM = matrix_colour_correction_Cheung2004(M_T, M_R, terms) return np.reshape(np.transpose(np.dot(CCM, np.transpose(RGB_e))), shape)
[docs]def colour_correction_Finlayson2015( RGB: ArrayLike, M_T: ArrayLike, M_R: ArrayLike, degree: Literal[1, 2, 3, 4] = 1, root_polynomial_expansion: Boolean = True, ) -> NDArray: """ Perform colour correction of given *RGB* colourspace array using the colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array using *Finlayson et al. (2015)* method. Parameters ---------- RGB *RGB* colourspace array to colour correct. M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. degree Expanded polynomial degree. root_polynomial_expansion Whether to use the root-polynomials set for the expansion. Returns ------- :class:`numpy.ndarray` Colour corrected *RGB* colourspace array. References ---------- :cite:`Finlayson2015` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> prng = np.random.RandomState(2) >>> M_T = prng.random_sample((24, 3)) >>> M_R = M_T + (prng.random_sample((24, 3)) - 0.5) * 0.5 >>> colour_correction_Finlayson2015(RGB, M_T, M_R) # doctest: +ELLIPSIS array([ 0.1793456..., 0.1003392..., 0.0617218...]) """ RGB = as_float_array(RGB) shape = RGB.shape RGB = np.reshape(RGB, (-1, 3)) RGB_e = polynomial_expansion_Finlayson2015( RGB, degree, root_polynomial_expansion ) CCM = matrix_colour_correction_Finlayson2015( M_T, M_R, degree, root_polynomial_expansion ) return np.reshape(np.transpose(np.dot(CCM, np.transpose(RGB_e))), shape)
[docs]def colour_correction_Vandermonde( RGB: ArrayLike, M_T: ArrayLike, M_R: ArrayLike, degree: Integer = 1 ) -> NDArray: """ Perform colour correction of given *RGB* colourspace array using the colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array using *Vandermonde* method. Parameters ---------- RGB *RGB* colourspace array to colour correct. M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. degree Expanded polynomial degree. Returns ------- :class:`numpy.ndarray` Colour corrected *RGB* colourspace array. References ---------- :cite:`Wikipedia2003e` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> prng = np.random.RandomState(2) >>> M_T = prng.random_sample((24, 3)) >>> M_R = M_T + (prng.random_sample((24, 3)) - 0.5) * 0.5 >>> colour_correction_Vandermonde(RGB, M_T, M_R) # doctest: +ELLIPSIS array([ 0.2128689..., 0.1106242..., 0.036213 ...]) """ RGB = as_float_array(RGB) shape = RGB.shape RGB = np.reshape(RGB, (-1, 3)) RGB_e = polynomial_expansion_Vandermonde(RGB, degree) CCM = matrix_colour_correction_Vandermonde(M_T, M_R, degree) return np.reshape(np.transpose(np.dot(CCM, np.transpose(RGB_e))), shape)
COLOUR_CORRECTION_METHODS = CanonicalMapping( { "Cheung 2004": colour_correction_Cheung2004, "Finlayson 2015": colour_correction_Finlayson2015, "Vandermonde": colour_correction_Vandermonde, } ) COLOUR_CORRECTION_METHODS.__doc__ = """ Supported colour correction methods. References ---------- :cite:`Cheung2004`, :cite:`Finlayson2015`, :cite:`Westland2004`, :cite:`Wikipedia2003e` """
[docs]def colour_correction( RGB: ArrayLike, M_T: ArrayLike, M_R: ArrayLike, method: Union[ Literal["Cheung 2004", "Finlayson 2015", "Vandermonde"], str ] = "Cheung 2004", **kwargs: Any, ) -> NDArray: """ Perform colour correction of given *RGB* colourspace array using the colour correction matrix from given :math:`M_T` colour array to :math:`M_R` colour array. Parameters ---------- RGB *RGB* colourspace array to colour correct. M_T Test array :math:`M_T` to fit onto array :math:`M_R`. M_R Reference array the array :math:`M_T` will be colour fitted against. method Computation method. Other Parameters ---------------- degree {:func:`colour.characterisation.polynomial_expansion_Finlayson2015`, :func:`colour.characterisation.polynomial_expansion_Vandermonde`}, Expanded polynomial degree, must be one of *[1, 2, 3, 4]* for :func:`colour.characterisation.polynomial_expansion_Finlayson2015` definition. root_polynomial_expansion {:func:`colour.characterisation.polynomial_expansion_Finlayson2015`}, Whether to use the root-polynomials set for the expansion. terms {:func:`colour.characterisation.matrix_augmented_Cheung2004`}, Number of terms of the expanded polynomial. Returns ------- :class:`numpy.ndarray` Colour corrected *RGB* colourspace array. References ---------- :cite:`Cheung2004`, :cite:`Finlayson2015`, :cite:`Westland2004`, :cite:`Wikipedia2003e` Examples -------- >>> RGB = np.array([0.17224810, 0.09170660, 0.06416938]) >>> M_T = np.array( ... [[0.17224810, 0.09170660, 0.06416938], ... [0.49189645, 0.27802050, 0.21923399], ... [0.10999751, 0.18658946, 0.29938611], ... [0.11666120, 0.14327905, 0.05713804], ... [0.18988879, 0.18227649, 0.36056247], ... [0.12501329, 0.42223442, 0.37027445], ... [0.64785606, 0.22396782, 0.03365194], ... [0.06761093, 0.11076896, 0.39779139], ... [0.49101797, 0.09448929, 0.11623839], ... [0.11622386, 0.04425753, 0.14469986], ... [0.36867946, 0.44545230, 0.06028681], ... [0.61632937, 0.32323906, 0.02437089], ... [0.03016472, 0.06153243, 0.29014596], ... [0.11103655, 0.30553067, 0.08149137], ... [0.41162190, 0.05816656, 0.04845934], ... [0.73339206, 0.53075188, 0.02475212], ... [0.47347718, 0.08834792, 0.30310315], ... [0.00000000, 0.25187016, 0.35062450], ... [0.76809639, 0.78486240, 0.77808297], ... [0.53822392, 0.54307997, 0.54710883], ... [0.35458526, 0.35318419, 0.35524431], ... [0.17976704, 0.18000531, 0.17991488], ... [0.09351417, 0.09510603, 0.09675027], ... [0.03405071, 0.03295077, 0.03702047]] ... ) >>> M_R = np.array( ... [[0.15579559, 0.09715755, 0.07514556], ... [0.39113140, 0.25943419, 0.21266708], ... [0.12824821, 0.18463570, 0.31508023], ... [0.12028974, 0.13455659, 0.07408400], ... [0.19368988, 0.21158946, 0.37955964], ... [0.19957425, 0.36085439, 0.40678123], ... [0.48896605, 0.20691688, 0.05816533], ... [0.09775522, 0.16710693, 0.47147724], ... [0.39358649, 0.12233400, 0.10526425], ... [0.10780332, 0.07258529, 0.16151473], ... [0.27502671, 0.34705454, 0.09728099], ... [0.43980441, 0.26880559, 0.05430533], ... [0.05887212, 0.11126272, 0.38552469], ... [0.12705825, 0.25787860, 0.13566464], ... [0.35612929, 0.07933258, 0.05118732], ... [0.48131976, 0.42082843, 0.07120612], ... [0.34665585, 0.15170714, 0.24969804], ... [0.08261116, 0.24588716, 0.48707733], ... [0.66054904, 0.65941137, 0.66376412], ... [0.48051509, 0.47870296, 0.48230082], ... [0.33045354, 0.32904184, 0.33228886], ... [0.18001305, 0.17978567, 0.18004416], ... [0.10283975, 0.10424680, 0.10384975], ... [0.04742204, 0.04772203, 0.04914226]] ... ) >>> colour_correction(RGB, M_T, M_R) # doctest: +ELLIPSIS array([ 0.1334872..., 0.0843921..., 0.0599014...]) """ method = validate_method(method, COLOUR_CORRECTION_METHODS) function = COLOUR_CORRECTION_METHODS[method] return function(RGB, M_T, M_R, **filter_kwargs(function, **kwargs))