Frequency of mismatching surface colors in the wild

Area of Science:

• Color Science
• Computer Vision
• Computational Imaging

Background:

• Surface colors can appear different under varying illumination conditions.
• Illuminant metamerism describes spectral changes, but real-world lighting is more complex.

Purpose of the Study:

• To computationally estimate the frequency of color mismatching for surfaces under natural, uncontrolled outdoor illumination changes.
• To assess the impact of natural lighting variations on surface color identification.

Main Methods:

• Utilized hyperspectral radiance images captured at various intervals (1 minute to over 4 hours).
• Analyzed pairs of randomly chosen surfaces within scenes to evaluate color appearance changes over time.
• Quantified the relative frequency of surfaces appearing initially the same and later different.

Main Results:

• The relative frequency of randomly chosen surfaces appearing initially the same and later different was low (10^-4 to 10^-3).
• However, surfaces that initially appeared the same showed a significantly higher frequency of mismatching later (6% to over 60%).
• This frequency is considerably higher than observed in studies of illuminant metamerism.

Conclusions:

• Natural, uncontrolled changes in outdoor illumination frequently cause color mismatching.
• The high frequency of mismatching, especially for surfaces initially appearing identical, suggests that real-world lighting variations can significantly impair color-based surface identification.