Specification of viewing conditions for color appearance modeling in naturalistic scenes

Perception is inherently complex, and color perception is no exception. Estimating color appearance under certain viewing conditions requires a clear understanding of the relevant information on each component involved. However, conventional color appearance models have been developed from psychophysical experiments under simple viewing conditions in which components follow Hunt's long-established framework. Although the influence of ambient illumination is evident, current models typically do not incorporate it directly; instead, users are required to compute its effect on the visual sensation prior to applying the model. To address this limitation, we propose a framework that specifies viewing conditions into three perceptually organized fields: the focal field, ambient field, and surrounding field. Unlike conventional definitions based on fixed spatial regions, our framework defines components according to perceptual organization. While less rigid than conventional definitions, this approach is more appropriate given that visual perception is an interpretation of visual sensation. The framework also introduces the proximus, a substitute for Hunt's proximal field, to incorporate local configurations related to the stimulus. By establishing these minimal yet essential components of complex viewing conditions, the framework lays the foundation for more comprehensive future investigations for the quantification of color appearance in naturalistic scenes.