Investigating von Kries‐like adaptation using local linear models

Minimal Von Kries illuminant invariance

“…In the early 1960s, Soviet Admiral S. G. Gorshkov declared, ''Perfect is the enemy of good enough.'' Mindful that Von Kries invariance holds up better than expected using the West and Brill criterion of ''perfection,'' Finlayson et al 7 developed a more gentle form of the criterion by dividing the spectrum up into regions separately ruled each by a single tristimulus channel, and hence separately (not jointly) constrained by spectral assumptions. The present article suggests two different approaches that may show us how to apply the criterion of ''perfect invariance,'' which otherwise might discourage practical use of the ''good-enough invariance'' actually achieved: Examine how adherence to the criterion is improved through optimal spectral sharpening, and examine other problems (such as Imura's) that have analogous mathematics.…”

The von Kries Hypothesis and a Basis for Color Constancy

“…There are the works of [7,16] that give necessary and sufficient conditions for von Kries compatibility under a predetermined choice of color space, and are able to build infinite dimensional von Kries compatible worlds for this choice. Then there are the works of [5,4] that prescribe a method for choosing the color space, but only for worlds with low dimensional linear spaces of illuminants and materials.…”

“…One case from [16] is explained in detail in [7]. They fix a color space, a space of material spectra, and a single reference illumination spectrum.…”

“…Empirical studies suggest that diagonal color constancy is adequate under more general conditions than the 2-3 model implies [7]. (This is good news for vision systems that seek color constancy in the real world.…”

“…Indeed, once a specific color basis is chosen, one can expand the set of compatible illuminants well beyond a two-dimensional space by adding those illuminants that integrate to zero against (i.e., are black with respect to) all reflectances in the compatible set [7]. More surprisingly, one can algorithmically grow the compatible illuminant set to include additional non-black illuminants as well [16,7]. This analysis, however, is still incomplete because given color data, the analysis does not reveal a method for computing the color space to begin with.…”