Spatial and Angular Variations of Colour Rendition due to Interreflections

The effective illuminance in a real-world scene is a geometrically weighted sum of direct and indirect components, and varies spatially and directionally, which is captured by the so-called light field. The spectral power distribution (SPD) of the indirect illuminance is dependent on that of the direct illuminance and the surface spectral reflectance (SSR) of the scene materials. The SPD of the indirect illuminance was derived to show systematic brightness, saturation and hue shifts due to inter-reflections. Differences between the spectral shapes of the direct and indirect illuminance induce colour rendition variations over the light fields, which we here investigate for uni-chromatic spaces.