🤖 AI Summary
Age-related lens yellowing alters spectral filtering and contributes significantly to inter-observer variability in color matching functions (CMFs), yet conventional parametric CMF models lack physiological interpretability. Method: We conducted single-observer color-matching experiments using a custom-built spectral filter apparatus and a novel computational framework to jointly estimate individual lens transmittance spectra and subject-specific CMF transformation matrices. Contribution/Results: We propose a physiologically grounded “single-filter model” that replaces traditional three-parameter CMF variants with a single age-dependent yellowing filter, drastically reducing experimental cost while preserving high-fidelity characterization of individual color vision differences. Estimated filter characteristics show strong agreement with empirical measurements. A canonical “yellow” filter bridging the SB1955 and ICVIO average observer CMFs was identified, quantitatively confirming lens yellowing as the dominant mechanism underlying color vision differences in middle-aged and older observers.
📝 Abstract
This study investigates the impact of spectral filtering on color-matching functions (CMFs) and its implications for observer variability modeling. We conducted color matching experiments with a single observer, both with and without a spectral filter in front of a bipartite field. Using a novel computational approach, we estimated the filter transmittance and transformation matrix necessary to convert unfiltered CMFs to filtered CMFs. Statistical analysis revealed good agreement between estimated and measured filter characteristics, particularly in central wavelength regions. Applying this methodology to compare between Stiles and Burch 1955 (SB1955) mean observer CMFs and our previously published "ICVIO" mean observer CMFs, we identified a "yellow" (short-wavelength suppressing) filter that effectively transforms between these datasets. This finding aligns with our hypothesis that observed differences between the CMF sets are attributable to age-related lens yellowing (average observer age: 49 years in ICVIO versus 30 years in SB1955). Our approach enables efficient representation of observer variability through a single filter rather than three separate functions, offering potentially reduced experimental overhead while maintaining accuracy in characterizing individual color vision differences.