Vision: Basics

Question 1

what is light?

Answer 1

a form of electromagnetic radiation

Question 2

smallest unit

Answer 2

a photon. 1 photon is a tiny “quantum” of energy

Question 3

wavelength

Answer 3

the distance between peaks of lightwave in nanometers. shorter wavelengths are purple-blue, longer wavelengths are red

Question 4

visible light

Answer 4

a subjective term as we see roughly 350 - 750 nm. bees can see uv and snakes and see infrared

Question 5

visual fields

Answer 5

all that you see without head or eye movement. each eye has its own field and usually overlap

Question 6

acuity

Answer 6

visual system’s ability to resolve fine detail

Question 7

fovea

Answer 7

name for the place in central vision where greatest acuity is found, high density of receptors in fovea

Question 8

visual receptors

Answer 8

basic light receiving units come in 2 flavours: rods and cones. they stimulate other neurons whose axons form the optic nerve

Question 9

optic disk

Answer 9

since there is a blind spot in the eye, this corresponds to the location where the axons of the optic nerve exit the eyeball

Question 10

brightness

Answer 10

an axis from light to dark

Question 11

hue

Answer 11

an axis through the rainbow

Question 12

saturation

Answer 12

an axis from solid grey through to intense hues

Question 13

what are the components of colour?

Answer 13

brightness, hue, saturation

Question 14

subjective brightness

Answer 14

the brightness you percieve. your visual system is usually only operating on 1/5 of the total brightness, meaning your perception of a bright object is relative to the range youre working in

Question 15

motion

Answer 15

our visual systems are especially tuned to motion where movement in peripheral vision captures attention