Investigating color perceptual similarity well above threshold

While the definition of perceptually uniform color models gathered a deep research effort in the last decades, the case of large color differences is still relatively unexplored. Indeed, metric spaces like CIELAB hold the uniformity property only locally, meaning over small color distances. This sets a serious drawback in the use of these models in color imaging application, where the assessment of the perceptual difference among colors lying far apart in the color space is most often required. This calls for the definition of a color difference formula enabling the objective evaluation of the perceived distance among colors well above threshold. One of the most important contribution in this respect is that of Seaborn et al. [Seaborn, Hepplewhite, and Stonham. Fuzzy color category map for the measurement of color similarity and dissimilarity. (2005)] who proposed a new colour space providing the ability to measure similarity and dissimilarity among colors using the combination of fuzzy logic and psychologically based set theoretic similarity measurement. On the other hand, other studies in the linguistic domain proposed to exploit the perceptual distance between colors for investigating whether linguistic differences induce differences in subjective judgments (e.g.,[ Kay and Kempton. What is the Sapir-Whorf hypothesis? (1984)]). In this work, we provide some evidence in favor of such a hypothesis by focusing on the specific case of the Italian language.