colour.temperature Package¶
Module Contents¶
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colour.temperature.
CCT_to_uv
(CCT, D_uv=0, method=u'Ohno 2013', **kwargs)[source]¶ Returns the CIE UCS colourspace uv chromaticity coordinates from given correlated colour temperature \(T_{cp}\) and \(\Delta_{uv}\) using given method.
Parameters: - CCT (numeric) – Correlated colour temperature \(T_{cp}\).
- D_uv (numeric) – \(\Delta_{uv}\).
- method (unicode, optional) – {‘Ohno 2013’, ‘Robertson 1968’}, Computation method.
- **kwargs (dict, optional) – Keywords arguments.
Returns: CIE UCS colourspace uv chromaticity coordinates.
Return type: ndarray
Raises: ValueError
– If the computation method is not defined.Examples
>>> from colour import STANDARD_OBSERVERS_CMFS >>> cmfs = 'CIE 1931 2 Degree Standard Observer' >>> cmfs = STANDARD_OBSERVERS_CMFS.get(cmfs) >>> CCT = 6507.4342201047066 >>> D_uv = 0.003223690901512735 >>> CCT_to_uv(CCT, D_uv, cmfs=cmfs) array([ 0.1978003..., 0.3122005...])
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colour.temperature.
CCT_to_uv_Ohno2013
(CCT, D_uv=0, cmfs=<colour.colorimetry.cmfs.XYZ_ColourMatchingFunctions object>)[source]¶ Returns the CIE UCS colourspace uv chromaticity coordinates from given correlated colour temperature \(T_{cp}\), \(\Delta_{uv}\) and colour matching functions using Ohno (2013) method.
Parameters: - CCT (numeric) – Correlated colour temperature \(T_{cp}\).
- D_uv (numeric, optional) – \(\Delta_{uv}\).
- cmfs (XYZ_ColourMatchingFunctions, optional) – Standard observer colour matching functions.
Returns: CIE UCS colourspace uv chromaticity coordinates.
Return type: ndarray
References
[4] Ohno, Y. (2014). Practical Use and Calculation of CCT and Duv. LEUKOS, 10(1), 47–55. doi:10.1080/15502724.2014.839020 Examples
>>> from colour import STANDARD_OBSERVERS_CMFS >>> cmfs = 'CIE 1931 2 Degree Standard Observer' >>> cmfs = STANDARD_OBSERVERS_CMFS.get(cmfs) >>> CCT = 6507.4342201047066 >>> D_uv = 0.003223690901512735 >>> CCT_to_uv_Ohno2013(CCT, D_uv, cmfs) array([ 0.1978003..., 0.3122005...])
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colour.temperature.
CCT_to_uv_Robertson1968
(CCT, D_uv=0)[source]¶ Returns the CIE UCS colourspace uv chromaticity coordinates from given correlated colour temperature \(T_{cp}\) and \(\Delta_{uv}\) using Roberston (1968) method.
Parameters: - CCT (numeric) – Correlated colour temperature \(T_{cp}\).
- D_uv (numeric) – \(\Delta_{uv}\).
Returns: CIE UCS colourspace uv chromaticity coordinates.
Return type: ndarray
References
[7] Wyszecki, G., & Stiles, W. S. (2000). DISTRIBUTION TEMPERATURE, COLOR TEMPERATURE, AND CORRELATED COLOR TEMPERATURE. In Color Science: Concepts and Methods, Quantitative Data and Formulae (pp. 224–229). Wiley. ISBN:978-0471399186 [8] Adobe Systems. (2013). Adobe DNG Software Development Kit (SDK) - 1.3.0.0 - dng_sdk_1_3/dng_sdk/source/dng_temperature.cpp:: dng_temperature::xy_coord. Retrieved from https://www.adobe.com/support/downloads/dng/dng_sdk.html Examples
>>> CCT = 6500.0081378199056 >>> D_uv = 0.0083333312442250979 >>> CCT_to_uv_Robertson1968(CCT, D_uv) array([ 0.1937413..., 0.3152210...])
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colour.temperature.
uv_to_CCT
(uv, method=u'Ohno 2013', **kwargs)[source]¶ Returns the correlated colour temperature \(T_{cp}\) and \(\Delta_{uv}\) from given CIE UCS colourspace uv chromaticity coordinates using given method.
Parameters: - uv (array_like) – CIE UCS colourspace uv chromaticity coordinates.
- method (unicode, optional) – {‘Ohno 2013’, ‘Robertson 1968’}, Computation method.
- **kwargs (dict, optional) – Keywords arguments.
Returns: Correlated colour temperature \(T_{cp}\), \(\Delta_{uv}\).
Return type: ndarray
Raises: ValueError
– If the computation method is not defined.Examples
>>> from colour import STANDARD_OBSERVERS_CMFS >>> cmfs = 'CIE 1931 2 Degree Standard Observer' >>> cmfs = STANDARD_OBSERVERS_CMFS.get(cmfs) >>> uv = np.array([0.1978, 0.3122]) >>> uv_to_CCT(uv, cmfs=cmfs) array([ 6.5075470...e+03, 3.2236908...e-03])
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colour.temperature.
uv_to_CCT_Ohno2013
(uv, cmfs=<colour.colorimetry.cmfs.XYZ_ColourMatchingFunctions object>, start=1000, end=100000, count=10, iterations=6)[source]¶ Returns the correlated colour temperature \(T_{cp}\) and \(\Delta_{uv}\) from given CIE UCS colourspace uv chromaticity coordinates, colour matching functions and temperature range using Ohno (2013) method.
The iterations parameter defines the calculations precision: The higher its value, the more planckian tables will be generated through cascade expansion in order to converge to the exact solution.
Parameters: - uv (array_like) – CIE UCS colourspace uv chromaticity coordinates.
- cmfs (XYZ_ColourMatchingFunctions, optional) – Standard observer colour matching functions.
- start (numeric, optional) – Temperature range start in kelvins.
- end (numeric, optional) – Temperature range end in kelvins.
- count (int, optional) – Temperatures count in the planckian tables.
- iterations (int, optional) – Number of planckian tables to generate.
Returns: Correlated colour temperature \(T_{cp}\), \(\Delta_{uv}\).
Return type: ndarray
References
[3] Ohno, Y. (2014). Practical Use and Calculation of CCT and Duv. LEUKOS, 10(1), 47–55. doi:10.1080/15502724.2014.839020 Examples
>>> from colour import STANDARD_OBSERVERS_CMFS >>> cmfs = 'CIE 1931 2 Degree Standard Observer' >>> cmfs = STANDARD_OBSERVERS_CMFS.get(cmfs) >>> uv = np.array([0.1978, 0.3122]) >>> uv_to_CCT_Ohno2013(uv, cmfs) array([ 6.5075470...e+03, 3.2236908...e-03])
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colour.temperature.
uv_to_CCT_Robertson1968
(uv)[source]¶ Returns the correlated colour temperature \(T_{cp}\) and \(\Delta_{uv}\) from given CIE UCS colourspace uv chromaticity coordinates using Roberston (1968) method.
Parameters: uv (array_like) – CIE UCS colourspace uv chromaticity coordinates. Returns: Correlated colour temperature \(T_{cp}\), \(\Delta_{uv}\). Return type: ndarray References
[5] Wyszecki, G., & Stiles, W. S. (2000). DISTRIBUTION TEMPERATURE, COLOR TEMPERATURE, AND CORRELATED COLOR TEMPERATURE. In Color Science: Concepts and Methods, Quantitative Data and Formulae (pp. 224–229). Wiley. ISBN:978-0471399186 [6] Adobe Systems. (2013). Adobe DNG Software Development Kit (SDK) - 1.3.0.0 - dng_sdk_1_3/dng_sdk/source/dng_temperature.cpp:: dng_temperature::Set_xy_coord. Retrieved from https://www.adobe.com/support/downloads/dng/dng_sdk.html Examples
>>> uv = np.array([0.19374137599822966, 0.31522104394059397]) >>> uv_to_CCT_Robertson1968(uv) array([ 6.5000162...e+03, 8.3333289...e-03])
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colour.temperature.
CCT_to_xy
(CCT, method=u'Kang 2002')[source]¶ Returns the CIE XYZ tristimulus values xy chromaticity coordinates from given correlated colour temperature \(T_{cp}\) using given method.
Parameters: - CCT (numeric or array_like) – Correlated colour temperature \(T_{cp}\).
- method (unicode, optional) – {‘Kang 2002’, ‘CIE Illuminant D Series’}, Computation method.
Returns: xy chromaticity coordinates.
Return type: ndarray
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colour.temperature.
CCT_to_xy_Kang2002
(CCT)[source]¶ Returns the CIE XYZ tristimulus values xy chromaticity coordinates from given correlated colour temperature \(T_{cp}\) using Kang et al. (2002) method.
Parameters: CCT (numeric or array_like) – Correlated colour temperature \(T_{cp}\). Returns: xy chromaticity coordinates. Return type: ndarray Raises: ValueError
– If the correlated colour temperature is not in appropriate domain.References
[11] Kang, B., Moon, O., Hong, C., Lee, H., Cho, B., & Kim, Y. (2002). Design of advanced color: Temperature control system for HDTV applications. Journal of the Korean …, 41(6), 865–871. Retrieved from http://cat.inist.fr/?aModele=afficheN&cpsidt=14448733 Examples
>>> CCT_to_xy_Kang2002(6504.38938305) array([ 0.313426..., 0.3235959...])
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colour.temperature.
CCT_to_xy_CIE_D
(CCT)[source]¶ Converts from the correlated colour temperature \(T_{cp}\) of a CIE Illuminant D Series to the chromaticity of that CIE Illuminant D Series illuminant.
Parameters: CCT (numeric or array_like) – Correlated colour temperature \(T_{cp}\). Returns: xy chromaticity coordinates. Return type: ndarray Raises: ValueError
– If the correlated colour temperature is not in appropriate domain.References
[12] Wyszecki, G., & Stiles, W. S. (2000). CIE Method of Calculating D-Illuminants. In Color Science: Concepts and Methods, Quantitative Data and Formulae (pp. 145–146). Wiley. ISBN:978-0471399186 Examples
>>> CCT_to_xy_CIE_D(6504.38938305) array([ 0.3127077..., 0.3291128...])
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colour.temperature.
xy_to_CCT
(xy, method=u'McCamy 1992', **kwargs)[source]¶ Returns the correlated colour temperature \(T_{cp}\) from given CIE XYZ tristimulus values xy chromaticity coordinates using given method.
Parameters: - xy (array_like) – xy chromaticity coordinates.
- method (unicode, optional) – {‘McCamy 1992’, ‘Hernandez 1999’}, Computation method.
- **kwargs (dict, optional) – Keywords arguments.
Returns: Correlated colour temperature \(T_{cp}\).
Return type: numeric or ndarray
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colour.temperature.
xy_to_CCT_McCamy1992
(xy)[source]¶ Returns the correlated colour temperature \(T_{cp}\) from given CIE XYZ tristimulus values xy chromaticity coordinates using McCamy (1992) method.
Parameters: xy (array_like) – xy chromaticity coordinates. Returns: Correlated colour temperature \(T_{cp}\). Return type: numeric or ndarray References
[9] Wikipedia. (n.d.). Approximation. Retrieved June 28, 2014, from http://en.wikipedia.org/wiki/Color_temperature#Approximation Examples
>>> xy = np.array([0.31271, 0.32902]) >>> xy_to_CCT_McCamy1992(xy) 6504.3893830...
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colour.temperature.
xy_to_CCT_Hernandez1999
(xy)[source]¶ Returns the correlated colour temperature \(T_{cp}\) from given CIE XYZ tristimulus values xy chromaticity coordinates using Hernandez-Andres, Lee and Romero (1999) method.
Parameters: xy (array_like) – xy chromaticity coordinates. Returns: Correlated colour temperature \(T_{cp}\). Return type: numeric References
[10] Hernández-Andrés, J., Lee, R. L., & Romero, J. (1999). Calculating correlated color temperatures across the entire gamut of daylight and skylight chromaticities. Applied Optics, 38(27), 5703–5709. doi:10.1364/AO.38.005703 Examples
>>> xy = np.array([0.31271, 0.32902]) >>> xy_to_CCT_Hernandez1999(xy) array(6500.0421533...)