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=3.741771e-16, 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 (ITS-90)
(Preston-Thomas, 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 * 1e-9, 5500)
20472701909806.5...
-
colour.colorimetry.blackbody.blackbody_spectral_radiance(wavelength, temperature, c1=3.741771e-16, 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 (ITS-90)
(Preston-Thomas, 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 * 1e-9, 5500)
20472701909806.5...
-
colour.colorimetry.blackbody.blackbody_spd(temperature, shape=SpectralShape(360.0, 830.0, 1.0), c1=3.741771e-16, 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 (ITS-90)
(Preston-Thomas, 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...>
Colour 0.3