Depth perception Flashcards
(112 cards)
1
Q
Image from the real world is essentially…?
a. 2D
b. 3D
A
a. 2D
2
Q
Our perception of the world is…?
a. 2D
b. 3D
A
b. 3D
3
Q
Generally, people are quite accurate in judging ambient distances up to about 20 feet. How is this typically demonstrated?
A
Having people survey the scene, closing their eyes and walking to a predesignated object
4
Q
What are the 4 cues to depth?
A
1) Oculomotor cues
2) Pictorial cues (monocular cues)
3) Motion-produced cues
4) Binocular disparity
5
Q
What are oculomotor cues?
A
Cues that depend on our ability to sense the position of our eyes and tension in our eye muscles
6
Q
What are pictorial cues (monocular cues)?
A
Cues that can be depicted in a still picture
7
Q
What are motion-produced cues?
A
Cues that depend on the movement of the observer, or the movement of objects in the environment
8
Q
What are binocular disparity cues?
A
A cue that depends on the fact that slightly different images of a scene are formed on each eye
9
Q
Cues that depend on our ability to sense the position of our eyes and the tension in our eye muscles
This is known as…?
A
Oculomotor cues
10
Q
Cues that can be depicted in a still picture
This is known as…?
A
Pictorial cues (monocular cues)
11
Q
Cues that depend on the movement of the observer, or the movement of objects in the environment
This is known as…?
A
Motion-produced cues
12
Q
A cue that depends on the fact that slightly different images of a scene are formed on each eye
This is known as…?
A
Binocular disparity
13
Q
Look at your finger as you hold it at arm’s length. Then slowly move your finger towards your nose. Be aware of how, as your finger moves closer, you feel your eyes looking inward and you feel increasing tension inside your eyes.
What cue is this?
A
Oculomotor cues
14
Q
What are the 2 feelings you experience when following Oculomotor cues?
A
1) Convergence as your eye muscles cause your eyes to look inward
2) Accommodation as the lens bulges to focus on a near object)
15
Q
When following oculomotor cues, you’ll experience convergence. What happens during convergence?
A
Your eye muscles cause your eyes to look inward
16
Q
When following oculomotor cues, you’ll experience accommodation. What happens during accommodation?
A
Our eye lens bulges to focus on a near object
17
Q
The shape of the lens and position of the eyes are correlated with …?
A
The distance of the object we are observing
18
Q
Which cues are only effective at distances closer than 5-10 feet?
A
Oculomotor cues
19
Q
Oculomotor cues are only effective at what distance?
A
Distances closer than 5 – 10 feet
20
Q
The closer the object the (weaker/greater) the convergence
A
Greater
21
Q
How does the eye accommodate for close vision?
A
By contracting/tightening the ciliary muscles, allowing the pliable crystalline lens to become more rounded
22
Q
The eye contracts/tightens the ciliary muscles, allowing the pliable crystalline lens to become more rounded
Why does it do this?
A
To accommodate for close/near vision
23
Q
The closer you are looking at an object, the (less/more) contraction there will be
A
More
24
Q
How does the eye accommodate far vision?
A
The eye relaxes the ciliary muscles, allowing the pliable crystalline lens to be at minimum strength for distant vision
25
Do fibres taut or slack for far vision?
Taut
26
Do fibres taut or slack for near vision?
Slack
27
Do lenses round or flatten for near vision?
Round
28
When the eye accommodates far vision, what happens to light rays coming into the eye?
Light rays from distant objects are nearly parallel and don't need as much refraction to bring them to a focus
29
When the eye accommodates near vision, what happens to light rays coming into the eye?
Light rays from close objects diverge and require more refraction for focusing
30
What is considered normal vision in terms of light rays hitting the retina?
Light is focused on the retina exactly
31
What is considered myopic vision in terms of light rays hitting the retina?
Light focused in front of the retina (too much-focusing power)
32
What is considered hyperopic vision in terms of light rays hitting the retina?
Light focused behind the retina (too weak focusing power)
33
Is myopia short-sightedness or long-sightedness?
Short-sightedness
34
Is hyperopia short-sightedness or long-sightedness?
Long-sightedness
35
What happens when myopia is corrected?
Light focused on the retina exactly by using a spectacle lens
36
Which depth cues do not require viewing with both eyes to work?
Pictorial cues
37
True or False
Pictorial cues require viewing with both eyes to work
False
They do not require viewing with both eyes to work
38
Which depth cue is often better to view monocularly?
Pictorial cues
39
True or False?
Pictorial cues are often better to view binocularly
Pictorial cues are often better to view monocularly
40
Define interposition or occlusion (pictorial cue)
One object obscures part of another or overlaps with it
41
A visual-perceptual task in which the participant is required to synthesize elements from fragmented, ambiguous pictures of items to form a “whole.”
This is known as...?
Gastault completion
42
What are the types of pictorial cues? List 9
1) Overlap/interposition/occlusion
2) Relative size
3) Relative height
4) Atmospheric Perspective
5) Familiar size
6) Linear perspective
7) Shading and shadows
8) Texture gradient
9) Movement-produced cues
43
Define relative size (pictorial cue)
The retinal size of objects gets smaller as they get further away
44
The retinal size of objects gets smaller as they get further away
This is known as...?
Relative size
45
One object obscures part of another or overlaps with it
This is known as...?
Overlapping or interposition or occlusion
46
True or False?
An object can look the same size at different distances but retinal image size changes with distance
True
47
Increase distance
a) decrease retinal image size
b) increase retinal image size
a) decrease retinal image size
48
Decrease distance
a) decrease retinal image size
b) increase retinal image size
b) increase retinal image size
49
The fact that an object can look the same size regardless of changing retinal image size is referred to as ...?
Size constancy
50
Define size constancy
An object can look the same size regardless of changing retinal image size
51
What does Emmert's law state?
Objects that generate retinal images of the same size will look different in physical size if they appear to be located at different distances
52
Objects that generate retinal images of the same size will look different in physical size if they appear to be located at different distances
Which law proposes this?
Emmert's law
53
Emmert's law suggests that the perceived size of an object increases as its perceived distance from the observer ...?
a. Increases
b. Decreases
a. Increases
54
Emmert's law suggests that an object of constant size will project progressively smaller retinal images as its distance from the observer ...?
a. Increases
b. Decreases
a. Increases
55
According to Emmert's law, if the retinal images of two different objects at different distances are the same, the physical size of the object that's farther away must be ..... than the one that is closer.
a. Smaller
b. Larger
b. Larger
56
Define relative height (pictorial cue)
As objects get further away they get nearer to the horizon
Simply = If the objects are below eye height, the highest object is the furthest away and if the objects are above eye height then the lowest object is further away
57
If the objects are below eye height, the highest object is the furthest away and if the objects are above eye height then the lowest object is further away
This is known as...?
Relative height (pictorial cue)
58
Following relative height (pictorial cue), if the objects are below eye height the ...... is ........
a. Lowest object, furthest away
b. Highest object, furthest away
c. Lowest object, nearest
d. Highest object, nearest
b. Highest object, furthest away
59
Following relative height (pictorial cue), if the objects are above eye height then the .... is ....
a. Lowest object, furthest away
b. Highest object, furthest away
c. Lowest object, nearest
d. Highest object, nearest
a. Lowest object, furthest away
60
Define atmospheric perspective (pictorial cue)
Distant objects appear less sharp because of more air and particles to look through
61
Distant objects appear less sharp because of more air and particles to look through
This is known as...?
Atmospheric perspective (pictorial cue)
62
If the blue light is scattered more by the atmosphere, the scenery will appear bluer
True or False?
True
63
Define familiar size (pictorial cue)
When you recognise an object through your previous experience/knowledge (top-down processing) and know that they appear far away or near
e.g. You recognise the silhouettes of a giraffe (top-down processing) and know that they look as if they're far away
64
When you recognise an object through your previous experience/knowledge (top-down processing) and know that they appear far away or near
This is known as...?
Familiar size (pictorial cue)
65
Define linear perspective (pictorial cue)
Lines that are parallel in the scene converge as they get further away
Simply = When looking down a straight level road we see the parallel sides of the road meet in the horizon
66
Lines that are parallel in the scene converge as they get further away
Simply = When looking down a straight level road we see the parallel sides of the road meet in the horizon
This is known as...?
Linear perspective (pictorial cue)
67
What are attached shadows?
The shading that results from depth within an object
68
The shading that results from depth within an object is known as...?
Attached shadows
69
What does a shadow tell us?
The direction of the light source
70
What is a detached shadow?
The shading that results from depth independent of an object
71
The shading that results from depth independent of an object
This is known as...?
Detached shadows
72
What is texture gradient (pictorial cue)
When texture becomes smaller/finer as distance increases
Simply = When something repetitive gets further and further away from you, it becomes finer and finer
e.g. a field of sunflowers
73
When texture becomes smaller/finer as distance increases
Simply = When something repetitive gets further and further away from you, it becomes finer and finer
This is known as...?
Texture gradient (pictorial cue)
74
The closer we are to an object the more detail we can see of its surface texture. So objects with smooth textures are usually interpreted as being farther away.
This is known as...?
Texture gradient (pictorial cue)
75
What are the 2 types of movement-produced cues?
1) Motion parallax
2) Deletion and Accretion
76
Define motion parallax
As an observer moves relative to a 3-D scene, nearby objects appear to move rapidly whereas far objects appear to move slowly
77
As an observer moves relative to a 3-D scene, nearby objects appear to move rapidly whereas far objects appear to move slowly
This is known as...?
Motion parallax
78
Staring out of a train window:
Objects far away appear to be moving slowly or not at all and nearby objects appear to be moving quickly
This is an example of...?
Motion parallax
79
Motion parallax involves 2 things. What are they?
1) Relative direction
2) Amount of motion
80
Motion parallax is used more by animals that ...?
Don’t have much binocular overlap (lack visuals that can be perceived with both eyes)
81
What are deletion movement-produced cues?
As one object moves in front of another, deletion occurs whereby the front object covers more of the back object.
82
As one object moves in front of another, deletion occurs whereby the front object covers more of the back object.
This is known as...?
Deletion movement-produced cues
83
As one object moves away from another, accretion occurs whereby the front object covers less of the back object.
This is known as...?
Accretion movement-produced cues
84
What are accretion movement-produced cues?
As one object moves away from another, accretion occurs whereby the front object covers less of the back object.
85
True or False?
As a front object moves, some parts of the object behind appear (accretion) and some disappear (deletion)
True
86
Binocular disparity is also known as...?
Binocular stereopsis
87
What is binocular disparity?
The difference between visuals that the 2 eyes have
88
The difference between the visuals that the 2 eyes have is known as...?
Binocular disparity
89
What does binocular disparity depend on?
Depends on two eyes & fact that our eyes see the world from slightly different positions determined by the distance between them
90
Depends on two eyes & fact that our eyes see the world from slightly different positions determined by the distance between them
Which depth cue is this?
Binocular disparity
91
Binocular disparity is the basis of...? List 2 things
Stereoscope and 3-D movies
92
With only your right eye open hold one finger upright about 6 inches in front of you. Then position a finger from your other hand about 6 inches further back, so that it is completely hidden by the front finger. Now close your right eye and open your left one, and the rear finger becomes visible. Since your left eye sees from a different point of view, it has looked around your front finger.
This is an example of...?
Binocular disparity
93
With binocular disparity, how do we see the world?
The brain fuses images seen on the left and right eye to perceive a full image of the world around us
94
When two eyes receive slightly different images of the same scene, we experience an impression of depth
Why?
Because of corresponding retinal points.
For every point on one retina, there is a corresponding point on the other.
These points would be identical if one retina was moved over to superimpose the other retina.
95
What are the corresponding retinal points?
Regions on the two retinae that would overlap if you slid one retina on top of the other
96
What happens when you fixate an object on corresponding retinal points?
When you fixate on an object it will stimulate corresponding points in the two eyes
97
What are the non-corresponding retinal points?
Regions on the two retinae that would not overlap if you slid one retina on top of the other
98
What happens when you fixate an object on non-corresponding retinal points?
These points are separated on the retinae and create disparity
99
Regions on the two retinae that would not overlap if you slid one retina on top of the other
This is known as...?
Non-Corresponding Retinal Points
100
Regions on the two retinae that would overlap if you slid one retina on top of the other
This is known as...?
Corresponding Retinal Points
101
What does the amount of disparity tell about objects?
How far one object is from another object
102
....% of people show stereo-blind performance and appear to lack mechanisms for processing disparities
2-5%
103
Which depth cue diminishes with distance?
Binocular disparity
104
Which depth cue is determined by the distance of the 2 eyes?
Binocular disparity
105
What can give increased depth from disparity?
Hyperstereo
106
Define hyperstereo
Hyperstereo is an image which uses a larger-than-normal distance between the left and right lenses
107
True or False?
Hyperstereo can be adapted as you get older
True
Children's eyes are closer together and the brain has to adapt to the change in disparity and eye distance as you get older
108
Julesz demonstrated that the visual system can use disparity information indirectly to generate a percept of depth
True or False?
False
Julesz demonstrated that the visual system can use disparity information directly to generate a percept of depth
109
How can we create a vivid sense of stereoscopic depth? AKA stereogram
1) Present the same image to both eyes but shift one slightly to the left or right
2) The shifted area will appear to be displaced in depth
3) This 3D image is called a stereogram
110
Define a stereogram
A stereogram is an optical illusion of depth created by a flat, two-dimensional image.
But if you view the image in a particular way, the three-dimensional image reveals itself in an uncanny way.
111
An optical illusion of depth created by a flat, two-dimensional image.
But if you view the image in a particular way, the three-dimensional image reveals itself in an uncanny way
This is known as...?
Stereogram
112
What are the 8 ways to make a stereogram?
1) Random dot stereogram
2) Animated autostereogram
3) Colour filters
4) Orthostereography
5) Shutter glasses (alternate left and right images)
6) Lenticular Displays/Printing
7) Parallax Barrier Technology (e.g. Nintendo 3DS)
8) Virtual reality
