Spectral sensitivities of the human cones

Area of Science:

• Vision science
• Photoreceptor physiology
• Colorimetry

Background:

• Cone isolation is crucial for understanding color vision.
• Transient chromatic adaptation offers a superior method for cone isolation compared to steady-state adaptation.
• Existing cone fundamentals show discrepancies, necessitating refinement.

Purpose of the Study:

• To measure middle-wave-sensitive (M)-cone and long-wavelength-sensitive (L)-cone spectral sensitivities using transient adaptation.
• To derive new cone fundamentals based on experimental data and compare them with existing models.
• To improve the accuracy of color vision models.

Main Methods:

• Employed transient chromatic adaptation for cone isolation.
• Measured M-cone spectral sensitivities in 11 normals and 2 protanopes.
• Measured L-cone spectral sensitivities in 12 normals and 4 deuteranopes.
• Derived new cone fundamentals using spectral-sensitivity data, tritanopic color-matching data, and Stiles' pi 3 function.

Main Results:

• M- and L-cone spectral-sensitivity functions showed little variation in shape across subjects.
• Mean spectral sensitivities agreed well with some existing dichromatic sensitivities and cone fundamentals (Smith & Pokorny, Vos & Walraven) based on CIE 2° CMFs.
• Agreement was poor with M-cone fundamentals based on Stiles-Burch 2° CMFs.
• New derived cone fundamentals showed consistency with various color vision data sets.

Conclusions:

• Transient adaptation is an effective technique for cone isolation.
• The newly derived cone fundamentals, based on Stiles-Burch 2° CMFs or CIE 10° CMFs, are more consistent and preferable over those based on CIE 2° CMFs.
• This research refines our understanding of cone spectral sensitivities and contributes to more accurate color vision models.