Colorimetry¶
- Spectral Data Structure
- Spectral Data Generation
- Conversion to Tristimulus Values
- Spectral Bandpass Dependence Correction
- Colour Matching Functions
- Colour Matching Functions Transformations
- Illuminants and Light Sources
- Dominant Wavelength and Purity
- Luminous Efficiency Functions
- Lightness Computation
- Luminance Computation
- Whiteness Computation
- Yellowness Computation
Spectral Data Structure¶
colour
SpectralPowerDistribution([data, domain]) |
Defines the spectral power distribution: the base object for spectral computations. |
MultiSpectralPowerDistribution([data, …]) |
Defines multi-spectral power distribution: the base object for multi spectral computations. |
SpectralShape([start, end, interval]) |
Defines the base object for spectral power distribution shape. |
DEFAULT_SPECTRAL_SHAPE |
Default spectral shape according to ASTM E308-15 practise shape. |
ASTME30815_PRACTISE_SHAPE |
Shape for *ASTM E308-15 practise* – (360, 780, 1). |
Spectral Data Generation¶
colour
blackbody_spd(temperature[, shape, c1, c2, n]) |
Returns the spectral power distribution of the planckian radiator for given temperature \(T[K]\). |
CIE_standard_illuminant_A_function(wl) |
CIE Standard Illuminant A is intended to represent typical, domestic, |
D_illuminant_relative_spd(xy) |
Returns the relative spectral power distribution of given CIE Standard Illuminant D Series using given xy chromaticity coordinates. |
constant_spd(k[, shape, dtype]) |
Returns a spectral power distribution of given spectral shape filled with constant \(k\) values. |
ones_spd([shape]) |
Returns a spectral power distribution of given spectral shape filled with ones. |
zeros_spd([shape]) |
Returns a spectral power distribution of given spectral shape filled with zeros. |
colour.colorimetry
blackbody_spectral_radiance(wavelength, …) |
Returns the spectral radiance of a blackbody at thermodynamic temperature \(T[K]\) in a medium having index of refraction \(n\). |
planck_law(wavelength, temperature[, c1, c2, n]) |
Returns the spectral radiance of a blackbody at thermodynamic temperature \(T[K]\) in a medium having index of refraction \(n\). |
Conversion to Tristimulus Values¶
colour
spectral_to_XYZ(spd[, cmfs, illuminant, method]) |
Converts given spectral power distribution to CIE XYZ tristimulus values using given colour matching functions, illuminant and method. |
SPECTRAL_TO_XYZ_METHODS |
Supported spectral power distribution to CIE XYZ tristimulus values |
wavelength_to_XYZ(wavelength[, cmfs]) |
Converts given wavelength \(\lambda\) to CIE XYZ tristimulus values using given colour matching functions. |
ASTM E308-15¶
colour.colorimetry
spectral_to_XYZ_ASTME30815(spd[, cmfs, …]) |
Converts given spectral power distribution to CIE XYZ tristimulus values using given colour matching functions and illuminant according to practise ASTM E308-15 method. |
Ancillary Objects
colour.colorimetry
spectral_to_XYZ_tristimulus_weighting_factors_ASTME30815(spd) |
Converts given spectral power distribution to CIE XYZ tristimulus values using given colour matching functions and illuminant using a table of tristimulus weighting factors according to practise ASTM E308-15 method. |
adjust_tristimulus_weighting_factors_ASTME30815(W, …) |
Adjusts given table of tristimulus weighting factors to account for a shorter wavelengths range of the test spectral shape compared to the reference spectral shape using practise ASTM E308-15 method: Weights at the wavelengths for which data are not available are added to the weights at the shortest and longest wavelength for which spectral data are available. |
lagrange_coefficients_ASTME202211([…]) |
Computes the Lagrange Coefficients for given interval size using practise ASTM E2022-11 method. |
tristimulus_weighting_factors_ASTME202211(…) |
Returns a table of tristimulus weighting factors for given colour matching functions and illuminant using practise ASTM E2022-11 method. |
Integration¶
colour.colorimetry
spectral_to_XYZ_integration(spd[, cmfs, …]) |
Converts given spectral power distribution to CIE XYZ tristimulus values using given colour matching functions and illuminant according to classical integration method. |
Spectral Bandpass Dependence Correction¶
colour
bandpass_correction(spd[, method]) |
Implements spectral bandpass dependence correction on given spectral power distribution using given method. |
BANDPASS_CORRECTION_METHODS |
Supported spectral bandpass dependence correction methods. |
Stearns and Stearns (1988)¶
colour.colorimetry
bandpass_correction_Stearns1988(spd) |
Implements spectral bandpass dependence correction on given spectral power distribution using Stearns and Stearns (1988) method. |
Colour Matching Functions¶
colour.colorimetry
LMS_ConeFundamentals([data, domain, labels]) |
Implements support for the Stockman and Sharpe LMS cone fundamentals colour matching functions. |
RGB_ColourMatchingFunctions([data, domain, …]) |
Implements support for the CIE RGB colour matching functions. |
XYZ_ColourMatchingFunctions([data, domain, …]) |
Implements support for the CIE Standard Observers XYZ colour matching functions. |
Dataset
colour
CMFS |
Aggregated colour matching functions. |
LMS_CMFS |
LMS colour matching functions. |
RGB_CMFS |
CIE RGB colour matching functions. |
STANDARD_OBSERVERS_CMFS |
CIE Standard Observers XYZ colour matching functions. |
Colour Matching Functions Transformations¶
Ancillary Objects
colour.colorimetry
RGB_2_degree_cmfs_to_XYZ_2_degree_cmfs(…) |
Converts Wright & Guild 1931 2 Degree RGB CMFs colour matching functions into the CIE 1931 2 Degree Standard Observer colour matching functions. |
RGB_10_degree_cmfs_to_XYZ_10_degree_cmfs(…) |
Converts Stiles & Burch 1959 10 Degree RGB CMFs colour matching functions into the CIE 1964 10 Degree Standard Observer colour matching functions. |
RGB_10_degree_cmfs_to_LMS_10_degree_cmfs(…) |
Converts Stiles & Burch 1959 10 Degree RGB CMFs colour matching functions into the Stockman & Sharpe 10 Degree Cone Fundamentals spectral sensitivity functions. |
LMS_2_degree_cmfs_to_XYZ_2_degree_cmfs(…) |
Converts Stockman & Sharpe 2 Degree Cone Fundamentals colour matching functions into the CIE 2012 2 Degree Standard Observer colour matching functions. |
LMS_10_degree_cmfs_to_XYZ_10_degree_cmfs(…) |
Converts Stockman & Sharpe 10 Degree Cone Fundamentals colour matching functions into the CIE 2012 10 Degree Standard Observer colour matching functions. |
Illuminants and Light Sources¶
Dataset
colour
ILLUMINANTS |
Aggregated CIE illuminants chromaticity coordinates. |
ILLUMINANTS_RELATIVE_SPDS |
CIE illuminants relative spectral power distributions. |
HUNTERLAB_ILLUMINANTS |
Aggregated Hunter L,a,b illuminant dataset. |
LIGHT_SOURCES |
Aggregated light sources chromaticity coordinates. |
LIGHT_SOURCES_RELATIVE_SPDS |
Aggregated light sources spectral power distributions. |
Dominant Wavelength and Purity¶
colour
dominant_wavelength(xy, xy_n[, cmfs, reverse]) |
Returns the dominant wavelength \(\lambda_d\) for given colour stimulus \(xy\) and the related \(xy_wl\) first and \(xy_{cw}\) second intersection coordinates with the spectral locus. |
complementary_wavelength(xy, xy_n[, cmfs]) |
Returns the complementary wavelength \(\lambda_c\) for given colour stimulus \(xy\) and the related \(xy_wl\) first and \(xy_{cw}\) second intersection coordinates with the spectral locus. |
excitation_purity(xy, xy_n[, cmfs]) |
Returns the excitation purity \(P_e\) for given colour stimulus \(xy\). |
colorimetric_purity(xy, xy_n[, cmfs]) |
Returns the colorimetric purity \(P_c\) for given colour stimulus \(xy\). |
Luminous Efficiency Functions¶
colour
luminous_efficacy(spd[, lef]) |
Returns the luminous efficacy in \(lm\cdot W^{-1}\) of given spectral power distribution using given luminous efficiency function. |
luminous_efficiency(spd[, lef]) |
Returns the luminous efficiency of given spectral power distribution using given luminous efficiency function. |
luminous_flux(spd[, lef, K_m]) |
Returns the luminous flux for given spectral power distribution using given luminous efficiency function. |
mesopic_luminous_efficiency_function(Lp[, …]) |
Returns the mesopic luminous efficiency function \(V_m(\lambda)\) for given photopic luminance \(L_p\). |
Dataset
colour
LEFS |
Aggregated luminous efficiency functions. |
PHOTOPIC_LEFS |
Photopic luminous efficiency functions. |
SCOTOPIC_LEFS |
Scotopic luminous efficiency functions. |
Lightness Computation¶
colour
lightness(Y[, method]) |
Returns the Lightness \(L\) using given method. |
LIGHTNESS_METHODS |
Supported Lightness computations methods. |
Glasser, Mckinney, Reilly and Schnelle (1958)¶
colour.colorimetry
lightness_Glasser1958(Y) |
Returns the Lightness \(L\) of given luminance \(Y\) using Glasser et alii (1958) method. |
Wyszecki (1963)¶
colour.colorimetry
lightness_Wyszecki1963(Y) |
Returns the Lightness \(W\) of given luminance \(Y\) using Wyszecki (1963) method. |
CIE 1976¶
colour.colorimetry
lightness_CIE1976(Y[, Y_n]) |
Returns the Lightness \(L^*\) of given luminance \(Y\) using given reference white luminance \(Y_n\) as per CIE 1976 recommendation. |
Fairchild and Wyble (2010)¶
colour.colorimetry
lightness_Fairchild2010(Y[, epsilon]) |
Computes Lightness \(L_{hdr}\) of given luminance \(Y\) using Fairchild and Wyble (2010) method according to Michealis-Menten kinetics. |
Fairchild and Chen (2011)¶
colour.colorimetry
lightness_Fairchild2011(Y[, epsilon, method]) |
Computes Lightness \(L_{hdr}\) of given luminance \(Y\) using Fairchild and Chen (2011) method accordingly to Michealis-Menten kinetics. |
Luminance Computation¶
colour
luminance(LV[, method]) |
Returns the luminance \(Y\) of given Lightness \(L^*\) or given Munsell value \(V\). |
LUMINANCE_METHODS |
Supported luminance computations methods. |
Newhall, Nickerson and Judd (1943)¶
colour.colorimetry
luminance_Newhall1943(V) |
Returns the luminance \(R_Y\) of given Munsell value \(V\) using Newhall et alii (1943) method. |
CIE 1976¶
colour.colorimetry
luminance_CIE1976(Lstar[, Y_n]) |
Returns the luminance \(Y\) of given Lightness \(L^*\) with given reference white luminance \(Y_n\). |
ASTM D1535-08e1¶
colour.colorimetry
luminance_ASTMD153508(V) |
Returns the luminance \(Y\) of given Munsell value \(V\) using ASTM D1535-08e1 method. |
Fairchild and Wyble (2010)¶
colour.colorimetry
luminance_Fairchild2010(L_hdr[, epsilon]) |
Computes luminance \(Y\) of given Lightness \(L_{hdr}\) using Fairchild and Wyble (2010) method according to Michealis-Menten kinetics. |
Fairchild and Chen (2011)¶
colour.colorimetry
luminance_Fairchild2011(L_hdr[, epsilon, method]) |
Computes luminance \(Y\) of given Lightness \(L_{hdr}\) using Fairchild and Chen (2011) method accordingly to Michealis-Menten kinetics. |
Whiteness Computation¶
colour
whiteness([method]) |
Returns the whiteness \(W\) using given method. |
WHITENESS_METHODS |
Supported whiteness computations methods. |
Berger (1959)¶
colour.colorimetry
whiteness_Berger1959(XYZ, XYZ_0) |
Returns the whiteness index \(WI\) of given sample CIE XYZ tristimulus values using Berger (1959) method. |
Taube (1960)¶
colour.colorimetry
whiteness_Taube1960(XYZ, XYZ_0) |
Returns the whiteness index \(WI\) of given sample CIE XYZ tristimulus values using Taube (1960) method. |
Stensby (1968)¶
colour.colorimetry
whiteness_Stensby1968(Lab) |
Returns the whiteness index \(WI\) of given sample CIE L*a*b* colourspace array using Stensby (1968) method. |
ASTM E313¶
colour.colorimetry
whiteness_ASTME313(XYZ) |
Returns the whiteness index \(WI\) of given sample CIE XYZ tristimulus values using ASTM E313 method. |
Ganz and Griesser (1979)¶
colour.colorimetry
whiteness_Ganz1979(xy, Y) |
Returns the whiteness index \(W\) and tint \(T\) of given sample xy chromaticity coordinates using Ganz and Griesser (1979) method. |
CIE 2004¶
colour.colorimetry
whiteness_CIE2004(xy, Y, xy_n[, observer]) |
Returns the whiteness \(W\) or \(W_{10}\) and tint \(T\) or \(T_{10}\) of given sample xy chromaticity coordinates using CIE 2004 method. |
Yellowness Computation¶
colour
yellowness(XYZ[, method]) |
Returns the yellowness \(W\) using given method. |
YELLOWNESS_METHODS |
Supported yellowness computations methods. |
ASTM D1925¶
colour.colorimetry
yellowness_ASTMD1925(XYZ) |
Returns the yellowness index \(YI\) of given sample CIE XYZ tristimulus values using ASTM D1925 method. |
ASTM E313¶
colour.colorimetry
yellowness_ASTME313(XYZ) |
Returns the yellowness index \(YI\) of given sample CIE XYZ tristimulus values using ASTM E313 method. |