colour.colorimetry.photometry Module

Photometry

Defines photometric quantities computation related objects.

See also

Photometry IPython Notebook

References

[1]Wikipedia. (n.d.). Luminosity function. Retrieved October 20, 2014, from https://en.wikipedia.org/wiki/Luminosity_function#Details
[2]Ohno, Y., & Davis, W. (2008). NIST CQS simulation 7.4. Retrieved from http://cie2.nist.gov/TC1-69/NIST CQS simulation 7.4.xls
colour.colorimetry.photometry.luminous_flux(spd, lef=<colour.colorimetry.spectrum.SpectralPowerDistribution object at 0x2adc37ae3a90>, K_m=683)[source]

Returns the luminous flux for given spectral power distribution using the given luminous efficiency function.

Parameters:
  • spd (SpectralPowerDistribution) – test spectral power distribution
  • lef (SpectralPowerDistribution, optional) – \(V(\lambda)\) luminous efficiency function.
  • K_m (numeric, optional) – \(lm\cdot W^{-1}\) maximum photopic luminous efficiency
Returns:

Luminous flux
Return type:

numeric

Examples

>>> from colour import LIGHT_SOURCES_RELATIVE_SPDS
>>> spd = LIGHT_SOURCES_RELATIVE_SPDS.get('Neodimium Incandescent')
>>> luminous_flux(spd)  
23807.6555273...
colour.colorimetry.photometry.luminous_efficacy(spd, lef=<colour.colorimetry.spectrum.SpectralPowerDistribution object at 0x2adc37ae3a90>)[source]

Returns the luminous efficacy for given spectral power distribution using the given luminous efficiency function.

Parameters:
  • spd (SpectralPowerDistribution) – test spectral power distribution
  • lef (SpectralPowerDistribution, optional) – \(V(\lambda)\) luminous efficiency function.
Returns:

Luminous efficacy
Return type:

numeric

Examples

>>> from colour import LIGHT_SOURCES_RELATIVE_SPDS
>>> spd = LIGHT_SOURCES_RELATIVE_SPDS.get('Neodimium Incandescent')
>>> luminous_efficacy(spd)  
0.1994393...