Non-Orthogonal Reduction for Rendering Fluorescent Materials in Non-Spectral Engines

Alban Fichet
Intel Corporation
Laurent Belcour
Intel Corporation
Pascal Barla
INRIA

To appear in Computer Graphics Forum

paper supp. pdf code

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We introduce a method to render fluorescent materials in a non-spectral rendererer, exhibiting typical increased luminance and hue-shifting effects when the same materials are placed under a different lighting. Our method is based on a new reduction technique that accurately matches the spectral reference, significantly improving on previous work where a naive formulation of the fluorescence reradiation matrix reduction was used.


Abstract

We propose a method to accurately handle fluorescence in a non-spectral (e.g., tristimulus) rendering engine, showcasing color-shifting and increased luminance effects. Core to our method is a principled reduction technique that encodes the re-radiation into a low-dimensional matrix working in the space of the renderer’s Color Matching Functions (CMFs). Our process is independent of a specific CMF set and allows for the addition of a non-visible ultraviolet band during light transport. Our representation visually matches full spectral light transport for measured fluorescent materials even for challenging illuminants.