Metameric: Spectral Uplifting via Controllable Color Constraints

Spectral rendering is a crucial solution for photorealistic rendering. However, most available texture assets are RGB-only, and access to spectral content is limited. Uplifting methods that recover full spectral representations from RGB inputs have therefore received much attention. Yet, most methods are deterministic, while, in reality, there is no one-to-one mapping. As a consequence, the appearance of uplifted textures is fully determined under all illuminants. Hereby, metamers, which are materials with differing spectral responses that appear identical under a specific illumination, are excluded.