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Flashcards in Chapter 10 Deck (47):
1

cue approach to depth perception

an approach to explaining depth perception that focuses on identifying information in the retinal image along with information found when you aim and focus the eyes on an object correlated with depth in the scene

2

3 major depth cues

  1. Occulomotor
  2. Monocular
  3. Binocular

 

3

occulomotor cues

based on our ability to sense the position of our eyes and tension in eye muscles

convergence and accomodation

4

convergence

accomodation

moving eyes inward when we look at a nearby object

the change in lens shape that happens when we focus on objects at different distances

5

When are the convergence and accomodation cues useful?

Which is more effective?

When objects are close and useful up to a distance of an arm's length

Convergence

6

monocular cues

cues that work with one eye

accomodation

pictorial cues

movement-based cues

7

8 Pictorial cues

  1. Occlusion
  2. Relative height
  3. Relative size
  4. Perspective convergence
  5. Familiar size
  6. Atmospheric perspective
  7. Texture gradient
  8. Shadows

 

8

occlusion

when one object hides all or some part of another, the hidden one is further

does not indicate distance alone

9

relative height

Below the horizon: higher in field means farther

Above the horizon: lower in field means farther

10

relative size

when two objects are equal size, the one that is farther will take up less of your field of view than the closer one

Sometimes need general knowledge about object

11

familiar size

 

when is it most effective

judging distance based on prior knowledge about the objects

 

when there is no other depth info

12

perspective convergence

parallel lines converge as distance increases

13

atmospheric perspective

objects far away are less sharp than closer ones and have a slight blue tint

14

texture gradient

equally spaced things in a scene look to be more closely packed as distance increases

15

How do shadows aid depth perception?

gives info on location

enhance three dimensionality of objects

16

motion produced cues

motion parallax

deletion and accretion

17

motion parallax

why does this happen

as we move, closer objects move past us rapidly but farther objects seem to move slower

closer objects move greater distances across the retina

18

deletion and accretion

as you move sideways things become covered and some things become uncovered

19

steroscopic vision

two eyed depth perception

involves processes that take into account differences in the images formed on the left and right eyes

20

stereoscopic depth perception

depth perception created by input from both eyes

21

strabismus

misalignment of the eyes

22

binocular disparity

differences in the images on the left and right retinas

23

corresponding retinal points

points on the retina that overlap if the eyes are superimposed on top of each other

24

horopter

imaginary line that passes through fixation point

visual stimuli on this line have images that fall on corresponding retinal points

25

non corresponding points

images of objects not on horoptor fall on these

26

absolute disparity

the degree to which these objects deviate from falling on corresponding points in the retina

27

angle of disparity

the amount of absolute disparity

28

when does angle of disparity increase

the further away the image moves from the horopter

29

relative disparity

the difference in absolute disparities of objects in a scene

helps indicate where objects are located relative to one another

30

stereopsis

the impression of depth you perceive based on info given by binocular disparity

31

random dot stereogram

shows you can perceive depth in a display with no other depth information than disparity

32

correspondence problem

the issue of figuring out how the visual system determines which parts of the images in the left and right eyes correspond to one another

 

33

binocular depth cells

disparity-selective cells

neurons that respond to absolute disparity - responds best when stimuli presented to each eye creates a specific amount of absolute disparity

34

what can affect our ability to accurately perceive size

a lack of accurate depth information

35

visual angle

the angle of an object relative to the observer's eye

depends on both stimulus size and distance (moving closer increases the angle)

36

size constancy

the fact that our perception of an object's size is constant even when we view it from different distances

37

size-distance scaling equation

S=K(R x D)

S - perceived size

K - a constant

R - size of the retinal image

D - perceived distance

38

explain size constancy in terms of the size-distance equation

as a person walks away from you the size of their image on you retina gets smaller, but your perception of their distance gets larger

39

Emmert's law

the farther away an afterimage appears, the larger it will seem

40

3 visual illusions

Muller-Lyer Illusion

Ames room

Ponzo illusion

41

two theories on Muller-Lyer illusion

misapplied size constancy scaling

conflicting cues theory

42

explain conflicting cues theory

our perception of line length relies on the actual length of the line as well as the overall length of the figure

43

explanation for Ponzo illusion

misapplied scaling: top animal looks bigger because the depth info from the tracks make it look farther away

44

How does the Ames room work

the construction of the room causes person on the left to have a much smaller visual angle than the one on the right

size-distance scaling (perceived distance is the same, retinal image is different)

relative size

45

moon illusion

moon looks larger when its on the horizon than when its higher in the sky

46

apparent distance theory

for moon illusion

when its on the horizon, it looks farther because it is viewed across terrain which gives us depth info

when its higher in the sky its viewed in empty space with little depth info

47

angular size contrast theory

moon looks smaller when surrounded by larger objects