colour.colorimetry.luminance Module¶
Luminance \(Y\)¶
Defines luminance \(Y\) computation objects.
The following methods are available:
luminance_Newhall1943()
: luminance \(Y\) computation of given Munsell value \(V\) using Newhall, Nickerson and Judd (1943) method.luminance_ASTMD153508()
: luminance \(Y\) computation of given Munsell value \(V\) using ASTM D1535-08e1 method.luminance_CIE1976()
: luminance \(Y\) computation of given Lightness \(L^*\) as per CIE 1976 recommendation.
See also
-
colour.colorimetry.luminance.
luminance_Newhall1943
(V)[source]¶ Returns the luminance \(R_Y\) of given Munsell value \(V\) using Newhall et al. (1943) method.
Parameters: V (numeric or array_like) – Munsell value \(V\). Returns: luminance \(R_Y\). Return type: numeric or array_like Notes
- Input Munsell value \(V\) is in domain [0, 10].
- Output luminance \(R_Y\) is in range [0, 100].
References
[1] Newhall, S. M., Nickerson, D., & Judd, D. B. (1943). Final report of the OSA subcommittee on the spacing of the munsell colors. JOSA, 33(7), 385. doi:10.1364/JOSA.33.000385 Examples
>>> luminance_Newhall1943(3.74629715382) 10.4089874...
-
colour.colorimetry.luminance.
luminance_ASTMD153508
(V)[source]¶ Returns the luminance \(Y\) of given Munsell value \(V\) using ASTM D1535-08e1 method.
Parameters: V (numeric or array_like) – Munsell value \(V\). Returns: luminance \(Y\). Return type: numeric or array_like Notes
- Input Munsell value \(V\) is in domain [0, 10].
- Output luminance \(Y\) is in range [0, 100].
References
[4] ASTM International. (n.d.). ASTM D1535-08e1 Standard Practice for Specifying Color by the Munsell System. doi:10.1520/D1535-08E01 Examples
>>> luminance_ASTMD153508(3.74629715382) 10.1488096...
-
colour.colorimetry.luminance.
luminance_CIE1976
(Lstar, Y_n=100)[source]¶ Returns the luminance \(Y\) of given Lightness \(L^*\) with given reference white luminance \(Y_n\).
Parameters: - Lstar (numeric or array_like) – Lightness \(L^*\)
- Y_n (numeric or array_like) – White reference luminance \(Y_n\).
Returns: luminance \(Y\).
Return type: numeric or array_like
Notes
- Input Lightness \(L^*\) and reference white luminance \(Y_n\) are in domain [0, 100].
- Output luminance \(Y\) is in range [0, 100].
References
[2] Wyszecki, G., & Stiles, W. S. (2000). CIE 1976 (L*u*v*)-Space and Color-Difference Formula. In Color Science: Concepts and Methods, Quantitative Data and Formulae (p. 167). Wiley. ISBN:978-0471399186 [3] Lindbloom, B. (2003). A Continuity Study of the CIE L* Function. Retrieved February 24, 2014, from http://brucelindbloom.com/LContinuity.html Examples
>>> luminance_CIE1976(37.98562910) array(10.0800000...) >>> luminance_CIE1976(37.98562910, 95) array(9.5760000...)
-
colour.colorimetry.luminance.
LUMINANCE_METHODS
= CaseInsensitiveMapping({u'astm2008': <function luminance_ASTMD153508>, u'Newhall 1943': <function luminance_Newhall1943>, u'ASTM D1535-08': <function luminance_ASTMD153508>, u'CIE 1976': <function luminance_CIE1976>, u'cie1976': <function luminance_CIE1976>})¶ Supported luminance computations methods.
- LUMINANCE_METHODS : CaseInsensitiveMapping
- {‘Newhall 1943’, ‘ASTM D1535-08’, ‘CIE 1976’}
Aliases:
- ‘astm2008’: ‘ASTM D1535-08’
- ‘cie1976’: ‘CIE 1976’
-
colour.colorimetry.luminance.
luminance
(LV, method=u'CIE 1976', **kwargs)[source]¶ Returns the luminance \(Y\) of given Lightness \(L^*\) or given Munsell value \(V\).
Parameters: - LV (numeric or array_like) – Lightness \(L^*\) or Munsell value \(V\).
- method (unicode, optional) – {‘CIE 1976’, ‘Newhall 1943’, ‘ASTM D1535-08’}, Computation method.
Other Parameters: Y_n (numeric or array_like, optional) – {
luminance_CIE1976()
}, White reference luminance \(Y_n\).Returns: luminance \(Y\).
Return type: numeric or array_like
Notes
- Input LV is in domain [0, 100] or [0, 10] and optional luminance \(Y_n\) is in domain [0, 100].
- Output luminance \(Y\) is in range [0, 100].
Examples
>>> luminance(37.98562910) array(10.0800000...) >>> luminance(37.98562910, Y_n=100) array(10.0800000...) >>> luminance(37.98562910, Y_n=95) array(9.5760000...) >>> luminance(3.74629715, method='Newhall 1943') 10.4089874... >>> luminance(3.74629715, method='ASTM D1535-08') 10.1488096...