The calculated spectra from the hyperspectral camera are dependent on the trasmittance of the optical material, on the responsivity of the camera and on the illuminant spectra. The reflectance spectra are obtained by dividing each  calculated spectra by the spectra of a reference (with known spectrum) present in the scene. From the reflectance spectrum, it is possible to calculate the RGB with different illuminants by knowing the spectra of the light source. This rendering is important when we want to know how an artwork would appear with different illuminants, for example in a museum where we want to find a compromise between the satisfaction of the visitor and the damage to  the artwork caused by the energy delivered by the illumination, especially at short wavelength. Otherwise, using particular illluminants it is possible to increase the contrast between parts/pattern of an image, or solve situations of metamerism. This applications are important in restauration.

In the following picture we report the RGB of the Machbeth chart rendered with different  illuminants.

Fig.1, RGB of the Machbeth chart rendered with D50 illuminant 

Fig.2, RGB of the Machbeth chart rendered with F2 Cool White Fluorescent illuminant . 

Fig.3, RGB of the Machbeth chart rendered with D65 illuminant 

Fig.4, RGB of the Machbeth chart rendered with white LED illuminant