What is the unit in colour.SDS_ILLUMINANTS? How to use my own measured spectrum?

[kikdu]

Hello,

I want to perform a spectral upsampling using

colour.XYZ_to_sd(XYZ, method="Jakob 2019", cmfs=cmfs, illuminant=illuminant)

Instead of using one of the illuminants in colour.SDS_ILLUMINANTS, I want to use the spectrum of a white reference that I measured with a spectroradiometer (which is the estimation of the illuminant in my natural scene).

What is the unit in colour.SDS_ILLUMINANTS and how to transform my data to match the expected data ?

Thank you !

[KelSolaar]

Hi @kikdu,

The illuminants typically represent irradiance. Reflectance is always normalised and given as a percentage between [0, 100] and independent of the measurement illuminant.

Cheers,

Thomas