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
SpectralShape ([start, end, interval]) |
Defines the base object for spectral distribution shape. |
SpectralDistribution ([data, domain]) |
Defines the spectral distribution: the base object for spectral computations. |
MultiSpectralDistribution ([data, domain, labels]) |
Defines multi-spectral distribution: the base object for multi spectral computations. |
DEFAULT_SPECTRAL_SHAPE |
(360, 780, 1). |
ASTME30815_PRACTISE_SHAPE |
(360, 780, 1). |
Spectral Data Generation¶
colour
sd_CIE_standard_illuminant_A ([shape]) |
CIE Standard Illuminant A is intended to represent typical, domestic, tungsten-filament lighting. |
sd_CIE_illuminant_D_series (xy[, M1_M2_rounding]) |
Returns the spectral distribution of given CIE Illuminant D Series using given xy chromaticity coordinates. |
sd_blackbody (temperature[, shape, c1, c2, n]) |
Returns the spectral distribution of the planckian radiator for given temperature \(T[K]\). |
sd_constant (k[, shape, dtype]) |
Returns a spectral distribution of given spectral shape filled with constant \(k\) values. |
sd_ones ([shape]) |
Returns a spectral distribution of given spectral shape filled with ones. |
sd_zeros ([shape]) |
Returns a spectral distribution of given spectral shape filled with zeros. |
SD_GAUSSIAN_METHODS |
Supported gaussian spectral distribution computation methods. |
sd_gaussian (mu_peak_wavelength, sigma_fwhm) |
Returns a gaussian spectral distribution of given spectral shape using given method. |
SD_SINGLE_LED_METHODS |
Supported single LED spectral distribution computation methods. |
sd_single_led (peak_wavelength, fwhm[, …]) |
Returns a single LED spectral distribution of given spectral shape at given peak wavelength and full width at half maximum according to given method. |
SD_MULTI_LEDS_METHODS |
Supported multi LED spectral distribution computation methods. |
sd_multi_leds (peak_wavelengths, fwhm[, …]) |
Returns a multi LED spectral distribution of given spectral shape at given peak wavelengths and full widths at half maximum according to given method. |
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 \(n\). |
daylight_locus_function (x_D) |
Returns the daylight locus as xy chromaticity coordinates. |
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 \(n\). |
sd_gaussian_normal (mu, sigma[, shape]) |
Returns a gaussian spectral distribution of given spectral shape at given mean wavelength \(\mu\) and standard deviation \(sigma\). |
sd_gaussian_fwhm (peak_wavelength, fwhm[, shape]) |
Returns a gaussian spectral distribution of given spectral shape at given peak wavelength and full width at half maximum. |
sd_single_led_Ohno2005 (peak_wavelength, fwhm) |
Returns a single LED spectral distribution of given spectral shape at given peak wavelength and full width at half maximum according to Ohno (2005) method. |
sd_multi_leds_Ohno2005 (peak_wavelengths, fwhm) |
Returns a multi LED spectral distribution of given spectral shape at given peak wavelengths and full widths at half maximum according to Ohno (2005) method. |
Conversion to Tristimulus Values¶
colour
sd_to_XYZ (sd[, cmfs, illuminant, k, method]) |
Converts given spectral distribution to CIE XYZ tristimulus values using given colour matching functions, illuminant and method. |
SD_TO_XYZ_METHODS |
Supported spectral distribution to CIE XYZ tristimulus values conversion methods. |
multi_sds_to_XYZ (msd[, shape, cmfs, …]) |
Converts given multi-spectral distribution array \(msd\) with given spectral shape to CIE XYZ tristimulus values using given colour matching functions and illuminant. |
MULTI_SD_TO_XYZ_METHODS |
Supported multi-spectral array to CIE XYZ tristimulus values conversion methods. |
wavelength_to_XYZ (wavelength[, cmfs]) |
Converts given wavelength \(\lambda\) to CIE XYZ tristimulus values using given colour matching functions. |
ASTM E308-15¶
colour.colorimetry
sd_to_XYZ_ASTME30815 (sd[, cmfs, illuminant, …]) |
Converts given spectral distribution to CIE XYZ tristimulus values using given colour matching functions and illuminant according to practise ASTM E308-15 method. |
Ancillary Objects
colour.colorimetry
sd_to_XYZ_tristimulus_weighting_factors_ASTME30815 (sd) |
Converts given spectral 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
sd_to_XYZ_integration (sd[, cmfs, illuminant, k]) |
Converts given spectral distribution to CIE XYZ tristimulus values using given colour matching functions and illuminant according to classical integration method. |
multi_sds_to_XYZ_integration (msd, shape[, …]) |
Converts given multi-spectral distribution array \(msd\) with given spectral shape to CIE XYZ tristimulus values using given colour matching functions and illuminant. |
Spectral Bandpass Dependence Correction¶
colour
bandpass_correction (sd[, method]) |
Implements spectral bandpass dependence correction on given spectral distribution using given method. |
BANDPASS_CORRECTION_METHODS |
Supported spectral bandpass dependence correction methods. |
Stearns and Stearns (1988)¶
colour.colorimetry
bandpass_correction_Stearns1988 (sd) |
Implements spectral bandpass dependence correction on given spectral 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_SDS |
CIE illuminants spectral distributions. |
HUNTERLAB_ILLUMINANTS |
Aggregated Hunter L,a,b illuminant dataset. |
LIGHT_SOURCES |
Aggregated light sources chromaticity coordinates. |
LIGHT_SOURCES_SDS |
Aggregated light sources spectral 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 (sd[, lef]) |
Returns the luminous efficacy in \(lm\cdot W^{-1}\) of given spectral distribution using given luminous efficiency function. |
luminous_efficiency (sd[, lef]) |
Returns the luminous efficiency of given spectral distribution using given luminous efficiency function. |
luminous_flux (sd[, lef, K_m]) |
Returns the luminous flux for given spectral distribution using given luminous efficiency function. |
sd_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 \(L\) of given luminance \(Y\) 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 al.(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. |
intermediate_lightness_function_CIE1976 (Y[, Y_n]) |
Returns the intermediate value \(f(Y/Yn)\) in the Lightness \(L^*\) computation for 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 according 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 al.(1943) method.. |
CIE 1976¶
colour.colorimetry
luminance_CIE1976 (L_star[, Y_n]) |
Returns the luminance \(Y\) of given Lightness \(L^*\) with given reference white luminance \(Y_n\). |
intermediate_luminance_function_CIE1976 (f_Y_Y_n) |
Returns the luminance \(Y\) in the luminance \(Y\) computation for given intermediate value \(f(Y/Yn)\) using given reference white luminance \(Y_n\) as per CIE 1976 recommendation. |
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 according 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. |