Perception of saturation in natural objects

Abstract

The distribution of colors across a surface depends on the interaction between its surface properties, its shape, and the lighting environment. Shading, chroma, and lightness are positively correlated: points on the object that have high luminance also have high chroma. Saturation, typically defined as the ratio of chroma to lightness, is therefore relatively constant across an object. Here we explored to what extent this relationship affects perceived saturation of an object. Using images of hyperspectral fruit and rendered matte objects, we manipulated the lightness–chroma correlation (positive or negative) and asked observers which of two objects appeared more saturated. Despite the negative-correlation stimulus having greater mean and maximum chroma, lightness, and saturation than the positive, observers overwhelmingly chose the positive as more saturated. This suggests that simple colorimetric statistics do not accurately represent perceived saturation of objects—observers likely base their judgments on interpretations about the cause of the color distribution.

Cutting Corners to Suppress High-Order Modes in Mie Resonator Arrays

“…The generated reflectance spectra were utilized to predict the structural color output on the CIE 1931 2-degree Standard Observer color space , (see Supporting Information Section S2 for color predicting calculations). These calculated structural color outputs were converted to the CIE L * a * b * color space , to determine the color saturation as a ratio of chroma to lightness − (see Supporting Information Section S3 for color saturation calculations).…”