Wavelength and Light
Nan
omet
ers
Monochromators measure the power or energy at different wavelengths
Typical daylight SPDs vary
Superposition of Light SPDs
Rod Color Matching
Example Data: Rod Matches
Photopigment Absorptions
Rhodopsin Absorption Curve
Rhodopsin Predicts Matches
Cones and Color Matching (Roorda et al.)
Cone inner segments have a diameter of roughly 1-2 micron in foveola and much larger in the periphery. Here (foveolar edge) they are about 3-4 microns(330 microns ~ 1 deg)
Cone Color Matching Experiment
Color Matching Is An Important Illusion That Is Understood
Quantitatively
The Color Matching Experiment Is Linear
If
and matches
matches
then matches
More metamer examples; this is a big effect.
RGB
CIE RGB functions Response
InputSPD
Color Matching Experiment Equation
Standard CMFs (10 deg)
Single Unit Cone Photocurrent Measurements (Schnapf, Baylor et
al).
Current Recordings From a Cone
There are Three Types of Cone Wavelength Responsivity
Stimuli Causing Equal Cone Signals Match Perceptually
L
M
S L M S
Abs
orpt
ion
rate
Cone type
Behavioral CMFs are accurately predicted by cone responsivities
Color Matching and Context
Illumination And Color
Appearance Are Closely
Coupled Through
Color Constancy
Blue Blue SkySky
Direct Direct SunSun
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