Psych 267 Chapter 10

Front 1

Oculomotor Cues

Back 1

Oculomotor depth cues come from two sources. Convergence and accommodation.

Front 2

Convergence

Back 2

Inward movement of the eyes when we look at near objects.

Front 3

Accommodation

Back 3

Adjusting the shape of the lens to focus on nearby or far away objects.

Front 4

Monocular depth cues

Back 4

Pictorial cues. Occlusion. Relative height. Relative size. Perspective convergence.

Front 5

Pictorial cues

Back 5

depth information that can be derived using information present in pictures or scenes.

Front 6

Occlusion

Back 6

An object that is partially occluded by another is seen as being farther away

Front 7

Relative height

Back 7

Objects that are below the horizon and are higher in the visual field are seen as further away.

Front 8

Relative size

Back 8

When two objects are of equal size, the one that is farther away will take up less of your visual field.

Front 9

Perspective convergence

Back 9

When parallel lines extend out from an observer they are perceived as converging as distance increases.

Front 10

Monocular pictorial cues

Back 10

Familiar size. Atmospheric perspective. Texture gradient. Shadow cues. Motion parallax.

Front 11

Familiar size

Back 11

Judging distance based on the known size of objects in the scene.

Front 12

Atmospheric perspective

Back 12

More distant objects appear blurry and have a slight bluish colour. The further away an object is the more dust, water particles, smog, etc. we have to look through to see them.

Front 13

Texture gradient

Back 13

Elements that are equally spaced in a scene appear to be more closely packed at further distances. Relative size.

Front 14

Shadow cues

Back 14

Can also be used to infer the locations of objects within a scene. Shadows can enhance the 3 dimensionality of objects.

Front 15

Motion parallax

Back 15

Occurs when objects that are nearby move by us more quickly than objects that are far away.

Front 16

Binocular depth cues

Back 16

Your two eyes allow you to see in 3D using binocular cues. Each eye acts as a 'camera' with a slightly different view.

Front 17

Angle of disparity

Back 17

Difference between the corresponding point on the retina, and where the image lands on the retina.

Front 18

Absolute disparity

Back 18

The absolute difference between the position of the image on the retina and its corresponding point on the retina. The amount of disparity indicates the distance of the object from the horopter. Absolute disparity changes every time we change where we are fixating

Front 19

Relative disparity

Back 19

The difference in absolute disparity between two objects in a scene. As longs as objects remain stationary their relative disparities will be the same between saccades

Front 20

Stereopsis

Back 20

The impression of depth created through binocular disparity.

Front 21

Seeing in 3D

Back 21

Stereopsis. 3D movies present two images on the screen that are taken from cameras at two different viewing angles. Use filters to help you fuse the images together.

Front 22

Echolocation in bats

Back 22

Bats emit high frequency sounds and use the reflected sound waves to determine the identity, size, and location of objects.

Front 23

Physiology of depth perception

Back 23

recorded from neurons in area CIP while monkeys indicated whether two texture patterns matched. Neurons in area CIP responded to specific depth orientations. The same neurons also respond to disparity signals.

Front 24

Retinal disparity neurons in V1

Back 24

V1 contains neurons that are tuned to respond to specific amounts of absolute disparity. These cells compute the disparity between corresponding points of the retina in the two eyes.

Front 25

Size perception

Back 25

Size perception and depth perception are inherently linked. We use depth information to make judgements about size.

Front 26

Visual angle

Back 26

The angle of an object relative to the eye. The position and size of the object on the retina.

Front 27

Using depth cues to make size judgements

Back 27

Participants were asked to match the size of the comparison circle to test circles presented at different distances. Test circles were adjusted to be the same visual angle. If participants use only visual angle then comparison circle should always be adjusted to be the same size as the retinal image size of the test circle.

Front 28

Results (Holway and Boring): full depth cues

Back 28

Participants adjusted the comparison circle to be larger as the test circle was presented further away.

Front 29

Results (Holway and Boring): Monocular viewing

Back 29

Eliminated disparity signals.

Front 30

Results (Holway and Boring): Peephole viewing

Back 30

Eliminates motion parallax.

Front 31

Results (Holway and Boring): masking the walls

Back 31

Eliminates shadows and reflections.

Front 32

Size constancy

Back 32

The perception of an object's size remains constant despite changes in distance.

Front 33

Size-distance scaling

Back 33

S=K(RxD). S = objects perceived size. K = constant. R = retinal image size. D= perceived distance of the object. As an object moves further away R gets smaller, but D gets larger to adjust the perceived size.

Front 34

Size constancy and Emmert's law

Back 34

The size of an afterimage depends on the distance of the surface you are looking at. the further away the afterimage appears, the larger it seems.

Front 35

Familiar size

Back 35

Estimating the size of something in relation to the size of a familiar object.

Front 36

Visual illusions

Back 36

One way to understand size perception is to study how our visual system can be fooled. The illusion results from mis applied size constancy scaling.

Front 37

Conflicting cues theory

Back 37

We can still perceive a Muller-Lyer like effect even when corners are not present. Conflicting cues theory suggests that the overall length of one figure is longer, and so we also perceive the line as being longer.

Front 38

Ponzo Illusion

Back 38

The ponzo illusion also occurs because of mis applied size constancy scaling. The two objects are exactly the same size, but perspective convergence gives the illusion of depth. If the two objects are the same size on the retina and one is further away, it must be larger.

Front 39

Actions can be immune to visual illusions

Back 39

Participants fall victim to the illusion when estimating (ventral stream), but when grasping (dorsal stream).

Front 40

The Ames room illusion

Back 40

Also results from size-constancy scaling. When we view the room through a peephole the person on the left has a smaller retinal image size, but depth cues are not available, thus we perceive them as being shorter.