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Converts radiance ( W/sr/m2 ) in luminance ( cd/m2 ) depending on the wavelength.
Note that the computation uses the eye sensitivity which obviously depends on the wavelength. Generally, a given eye sensitivity corresponds to two wavelengths except for the maximum value reached at 0.555 nm. In the case where the wavelength is to calculate, the eye sensitivity is solved first and only the smallest wavelength corresponding to is calculated.
Note also that the wavelengths are considered between 0.38 microns and 0.825 microns.