Log Color Space Illumination Invariance

The patent transforms the traditional linear chromaticity representation into a logarithmic chromaticity space, changing the mathematical parameters from linear ratios to logarithmic transformations. This parameter change enables illumination invariance because the log transform converts multiplicative illumination effects into additive components that can be separated and removed, while maintaining computational feasibility through standardized image processing operations.

The patent introduces an intermediate chromaticity plane as a mediator between the original RGB color space and the final illumination-invariant material representation. This intermediate plane serves as a transformation space where illumination and reflectance components can be separated through geometric projection, acting as a bridge that enables accurate material identification without requiring direct complex calculations in the original color space.

The patent implements a dynamic chromaticity plane orientation that adapts to different illumination conditions, particularly bi-illuminant scenarios. Instead of using a fixed chromaticity plane, the system dynamically determines the optimal plane orientation based on the specific illumination environment, allowing accurate material representation whether under single Planckian illuminants or complex multi-illuminant conditions like shadow and highlight regions.

The patent creates a universal chromaticity representation framework that works across multiple illumination types and scenarios. The method is designed to handle both traditional Planckian illuminants and complex bi-illuminant situations, making it universally applicable to diverse real-world lighting conditions while maintaining a unified mathematical framework rather than requiring separate processing for different illumination types.