PPVK Vision 4 Flashcards
Color is not a ______ but a _________ property
physical, psychophysical
Most of the light we see is _______.
reflected (sun, bulb, fire)
Which part of electromagnetic spectrum eye sees (in nm)?
400 and 700 nm
Heterocromatic light (many wavelengths)
most of the light we see (common light sources)
Monochromatic (one wavelength)
one wavelength (laser beam)
Physical parameters for monochromatic light: _______ and _________
wavelength and intensity
intenzitet i valna duljina
What are three steps to color perception?
Detection - to detect wavelengths of light
Discrimination - tell the difference between one wavelength and another
Appearance - assign perceived colors to light and surfaces in the world
The principle of univariance
beskonačan skup različitih kombinacija valnih duljina i intenziteta može izazvati potpuno isti odgovor od jedne vrste fotoreceptora
under photopic conditions ____, ______ and ________ are all active.
S, M and L cones
Trichromacy theory of color vision
boja bilo kojeg svjetla definirana je u našem vizualnom sustavu odnosima triju brojeva, izlaza tri vrste receptora za koje se zna da su tri čunjića
Metamers
mješavine valnih duljina koje izgledaju identično
What kind of receptive fields do LGN cells have, and how are they stimulated?
They have center-surround receptive fields and are maximally stimulated by spots of light.
What is a cone-opponent cell?
output is based on a difference between sets of cones
What is special about cone-opponent cells in the LGN?
They have center-surround receptive fields and respond to differences between cones like (L+ M−) or (M+ L−).
What is unique about retinal ganglion cells with melanopsin?
They receive input from rods and cones but also contain their own photopigment, melanopsin, allowing them to detect light even without normal photoreceptors.
What functions are controlled by the outputs of melanopsin-containing retinal ganglion cells?
Their outputs go to brain centers that control non-visual functions like the circadian clock, and we don’t consciously perceive their signals.
Color space
3D dimension that describes all colors
RGB color space is defined by the outputs of:
long, medium and short wavelengths (R,G,B)
Nonspectral colors (example)
colors that we see that do not respond to a single wavelength of light
purple, magenta - S-L cones stimulated
Opponent color theory
kaže da boje doživljavamo kroz suprotstavljene parove – crvena nasuprot zelenoj, plava nasuprot žutoj i crna nasuprot bijeloj – što objašnjava zašto neke kombinacije boja, poput crvenkasto-zelene ili plavičasto-žute, nije moguće vidjeti.
Unique hue (jedinstvena nijansa)
any of the four colors that can be described with only a single color term: red, yellow, green, blue
Achromatopsia
loss of color vision from brain damage
Tetrachromatic vision
rare condition where a person has four types of cone cells in their eyes instead of the usual three allowing them to perceive a wider and more nuanced range of colors than the average person
Deuteranope
color blindness due to absence of M cones
RED GREEN COLOR BLIDNESS
