colour.sd_to_aces_relative_exposure_values

colour.sd_to_aces_relative_exposure_values(sd, illuminant=SpectralDistribution(name='D65', ...), apply_chromatic_adaptation=False, chromatic_adaptation_transform='CAT02')[source]

Converts given spectral distribution to ACES2065-1 colourspace relative exposure values.

Parameters
  • sd (SpectralDistribution) – Spectral distribution.

  • illuminant (SpectralDistribution, optional) – Illuminant spectral distribution.

  • apply_chromatic_adaptation (bool, optional) – Whether to apply chromatic adaptation using given transform.

  • chromatic_adaptation_transform (unicode, optional) – {‘CAT02’, ‘XYZ Scaling’, ‘Von Kries’, ‘Bradford’, ‘Sharp’, ‘Fairchild’, ‘CMCCAT97’, ‘CMCCAT2000’, ‘CAT02_BRILL_CAT’, ‘Bianco’, ‘Bianco PC’}, Chromatic adaptation transform.

Returns

ACES2065-1 colourspace relative exposure values array.

Return type

ndarray, (3,)

Notes

Range

Scale - Reference

Scale - 1

XYZ

[0, 100]

[0, 1]

  • The chromatic adaptation method implemented here is a bit unusual as it involves building a new colourspace based on ACES2065-1 colourspace primaries but using the whitepoint of the illuminant that the spectral distribution was measured under.

References

[For18], [TheAoMPAaSciencesScienceaTCouncilAcademyCESACESPSubcommittee14b], [TheAoMPAaSciencesScienceaTCouncilAcademyCESACESPSubcommittee14c], [TheAoMPAaSciencesScienceaTCouncilAcademyCESACESPSubcommittee]

Examples

>>> from colour import COLOURCHECKER_SDS
>>> sd = COLOURCHECKER_SDS['ColorChecker N Ohta']['dark skin']
>>> sd_to_aces_relative_exposure_values(sd)  
array([ 0.1171814...,  0.0866360...,  0.0589726...])
>>> sd_to_aces_relative_exposure_values(sd,
...     apply_chromatic_adaptation=True)  
array([ 0.1180779...,  0.0869031...,  0.0589125...])