pythoncolorsrgb

Converting multiple wavelengths to a single RGB value using the colour-science package

I'm working with a dataset that contains reflectance factor (Rf) values and their corresponding wavelengths, like this:

Rf          Wavelength
0.3907051   190
0.3907051   191
0.3907051   192
...
0.3907051   200

I am trying to convert the multiple wavelengths into a single RGB value using the colour-science package, but I’m having trouble finding relevant documentation on how to do this. How can I convert these wavelength-Rf pairs into a single RGB value?

Solution

  • https://colour.readthedocs.io/en/latest/tutorial.html should give you a good starting point. I do not know this package, but what I have extracted from the tutorial (links to the relevant sections shown in the comments):

    enter image description here

    import colour

# define the spectral distribution as a dict
# https://colour.readthedocs.io/en/latest/tutorial.html#from-spectral-distribution
data_sample = {
    380: 0.048,
    385: 0.051,
# [...]
    775: 0.432,
    780: 0.421,
}
sd = colour.SpectralDistribution(data_sample)
colour.plotting.plot_single_sd(sd)

# Calculate the tristimulus values from the spectral data
# https://colour.readthedocs.io/en/latest/tutorial.html#convert-to-tristimulus-values
cmfs = colour.MSDS_CMFS["CIE 1931 2 Degree Standard Observer"]
illuminant = colour.SDS_ILLUMINANTS["D65"]

XYZ = colour.sd_to_XYZ(sd, cmfs, illuminant)

# Convert to color
# https://colour.readthedocs.io/en/latest/tutorial.html#convert-to-display-colours
RGB = colour.XYZ_to_sRGB(XYZ / 100)
colour.plotting.plot_single_colour_swatch(colour.plotting.ColourSwatch(RGB, "Sample"), text_kwargs={"size": "x-large"})