Color Vision Flashcards
spectroradiometry
the measurement of optical radiant energy at each wavelength
radiometry
measurement of optical radiant energy
hue
the perceptual pigmentation difference experience with varying wavelengths ex: blue, green, etc.
brightness
the intensity of the hue, varies in relation to amplitude of the light
saturation
degree of white light mixed in with the dominant wavelength - perceptually experienced as the purity of the color
pure light
light which can be experienced as only one hue - light of a single wavelength
composite light
light comprised of many different wavelengths
spectral colors
Red to blue
non-spectral colors
combination of short and long ends of spectrum - purple, magenta, pink
color discrimination/wavelength discrimination
where the slopes of the cone absorption spectra change most rapidly with respect to each other
perception of saturation
wavelength dependent - least saturated at monochromatic stimulus of 570 nm
colorimetric purity
a physical property of a stimulus equal to:
luminance of the monochromatic light)/(sum of luminance of monochromatic light and luminance of white light added
monochromatic stimulus
no white light added to it. colorimetric purity of 1
Bezold-Brucke shift
monochromatic stimuli slightly change hue as their intensity is adjusted
unique hues
hue doesn’t change with intensity change - blue (478), green (503), and yellow (578)
color constancy
approximately constant color appearance of objects as light conditions change
munsell color appearance
describe colors with 3 physical dimensions: hue, chroma, and value
conceptualized as a cylinder containing various color samples
chroma
colorimetric purity and saturation of the color sample
value
reflectance of the sample/brightness
primary colors of munsell color appearance system
red, yellow, green, blue, and purple
hue measurement of munsell color appearance system
change measured by circumference around cylinder
chroma measurement of munsell color appearance system
radius away from cylinder (1-14).
highest purity = 14 (farthest from cylinder)
value measurement of munsell color appearance system
height on cylinder (0-10)
least reflectant = 0/most reflectant = 10
most direct measurement of the photopigment spectra
electrophysiological recordings of individual photoreceptors and molecular genetics
spectral sensitivity
the reciprocal of threshold wavelength function
function of wavelength
the amount of energy required to elicit a criterion response in an isolated cone
trichromatic theory
PHOTORECEPTOR
color is coded by (3) cones
evidence shown by color matching and color mixing studies
s cone
blue
m cone
green
l cone
red
color opponent theory
NEURAL
the photoreceptors are linked together to form three opposing color pairs (black/white, red/green, blue/yellow) activation of one inhibits another - explains complementary afterimage and color deficiency
