Blackbody  Planckian Radiator
Defines objects to compute the spectral radiance of a planckian radiator and
its spectral power distribution.

colour.colorimetry.blackbody.planck_law(wavelength, temperature, c1=3.741771e16, c2=0.014388, n=1)[source]
Returns the spectral radiance of a blackbody at thermodynamic temperature
\(T[K]\) in a medium having index of refraction \(n\).
Notes
The following form implementation is expressed in term of wavelength.
The SI unit of radiance is watts per steradian per square metre.
References
Parameters: 
 wavelength (numeric or array_like) – Wavelength in meters.
 temperature (numeric or array_like) – Temperature \(T[K]\) in kelvin degrees.
 c1 (numeric or array_like, optional) – The official value of \(c1\) is provided by the Committee on Data
for Science and Technology (CODATA), and is
\(c1=3,741771x10.16\ W/m_2\) (Mohr and Taylor, 2000).
 c2 (numeric or array_like, optional) – Since \(T\) is measured on the International Temperature Scale,
the value of \(c2\) used in colorimetry should follow that adopted
in the current International Temperature Scale (ITS90)
(PrestonThomas, 1990; Mielenz et aI., 1991), namely
\(c2=1,4388x10.2\ m/K\).
 n (numeric or array_like, optional) – Medium index of refraction. For dry air at 15°C and 101 325 Pa,
containing 0,03 percent by volume of carbon dioxide, it is
approximately 1,00028 throughout the visible region although
CIE 15:2004 recommends using \(n=1\).

Returns:  Radiance in watts per steradian per square metre.

Return type:  numeric or ndarray

Examples
>>> # Doctests ellipsis for Python 2.x compatibility.
>>> planck_law(500 * 1e9, 5500)
20472701909806.5...

colour.colorimetry.blackbody.blackbody_spectral_radiance(wavelength, temperature, c1=3.741771e16, c2=0.014388, n=1)
Returns the spectral radiance of a blackbody at thermodynamic temperature
\(T[K]\) in a medium having index of refraction \(n\).
Notes
The following form implementation is expressed in term of wavelength.
The SI unit of radiance is watts per steradian per square metre.
References
Parameters: 
 wavelength (numeric or array_like) – Wavelength in meters.
 temperature (numeric or array_like) – Temperature \(T[K]\) in kelvin degrees.
 c1 (numeric or array_like, optional) – The official value of \(c1\) is provided by the Committee on Data
for Science and Technology (CODATA), and is
\(c1=3,741771x10.16\ W/m_2\) (Mohr and Taylor, 2000).
 c2 (numeric or array_like, optional) – Since \(T\) is measured on the International Temperature Scale,
the value of \(c2\) used in colorimetry should follow that adopted
in the current International Temperature Scale (ITS90)
(PrestonThomas, 1990; Mielenz et aI., 1991), namely
\(c2=1,4388x10.2\ m/K\).
 n (numeric or array_like, optional) – Medium index of refraction. For dry air at 15°C and 101 325 Pa,
containing 0,03 percent by volume of carbon dioxide, it is
approximately 1,00028 throughout the visible region although
CIE 15:2004 recommends using \(n=1\).

Returns:  Radiance in watts per steradian per square metre.

Return type:  numeric or ndarray

Examples
>>> # Doctests ellipsis for Python 2.x compatibility.
>>> planck_law(500 * 1e9, 5500)
20472701909806.5...

colour.colorimetry.blackbody.blackbody_spd(temperature, shape=SpectralShape(360.0, 830.0, 1.0), c1=3.741771e16, c2=0.014388, n=1)[source]
Returns the spectral power distribution of the planckian radiator for given
temperature \(T[K]\).
Parameters: 
 temperature (numeric) – Temperature \(T[K]\) in kelvin degrees.
 shape (SpectralShape, optional) – Spectral shape used to create the spectral power distribution of the
planckian radiator.
 c1 (numeric, optional) – The official value of \(c1\) is provided by the Committee on Data
for Science and Technology (CODATA), and is
\(c1=3,741771x10.16\ W/m_2\) (Mohr and Taylor, 2000).
 c2 (numeric, optional) – Since \(T\) is measured on the International Temperature Scale,
the value of \(c2\) used in colorimetry should follow that adopted
in the current International Temperature Scale (ITS90)
(PrestonThomas, 1990; Mielenz et aI., 1991), namely
\(c2=1,4388x10.2\ m/K\).
 n (numeric, optional) – Medium index of refraction. For dry air at 15°C and 101 325 Pa,
containing 0,03 percent by volume of carbon dioxide, it is
approximately 1,00028 throughout the visible region although
CIE 15:2004 recommends using \(n=1\).

Returns:  Blackbody spectral power distribution.

Return type:  SpectralPowerDistribution

Examples
>>> from colour import STANDARD_OBSERVERS_CMFS
>>> cmfs = STANDARD_OBSERVERS_CMFS.get(
... 'CIE 1931 2 Degree Standard Observer')
>>> blackbody_spd(5000, cmfs.shape)
<colour.colorimetry.spectrum.SpectralPowerDistribution object at 0x...>