Depth Perception

Question 1

What is Oculomotor?

Answer 1

Cues based on sensing the position of the eyes and muscle tension.

Question 2

What is Convergence?

Answer 2

Inward movement of the eyes when we focus on nearby objects.

Question 3

What is Accommodation?

Answer 3

Change in the shape of the lens when we focus on objects at different distances.

Question 4

What is Monocular Cues?

Answer 4

Come only from one eye.

Question 5

What is Binocular Cues?

Answer 5

Requires two normal functioning eyes.

Question 6

What is Occlusion (Interposition)?

Answer 6

When one object partially covers another object.
If object A blocks object B, then object A will appear closer than object B.

Question 7

What is Attached Shadow?

Answer 7

Provides depth cues from within the object itself.

Question 8

What is Cast Shadow?

Answer 8

Provides depth cues from the shadows that fall on surrounding surfaces.

Question 9

What is Relative Size?

Answer 9

Deals with separate objects and the changes in the size of their images.
If two objects are similar in size (physical reality), then the one that casts the larger image on the retina will be perceived as closer.

Question 10

What is Perspective Convergence (Linear Perspective)?

Answer 10

Parallel lines appear to converge as they get farther from you.
This cue is often combined with relative size cue to produce some interesting effects (i.e., Ponzo Illusion).

Question 11

What is Texture Gradient?

Answer 11

A cue provided by a surface with repeating elements or patterns.
Equally spaced elements are more closely packed as they get further from you. The detail is also lost as the elements get further from you.

Question 12

What is Aerial Perspective (Atmospheric Perspective)?

Answer 12

Variations in clarity and color.
As the object gets farther away, the image gets “fuzzier.”
As the object gets farther away, the image seems more “bluish.”

Question 13

What is Relative Height?

Answer 13

Relationship to the horizon line.
The closer the object is to the horizon, the farther away we perceive it (from you).
The farther the object is from the horizon, the closer it appears to be (from you).

Question 14

What is Motion Parallax?

Answer 14

Cues provided from the changes in images as you move.
Objects that are farther from you appear to move in the same direction as you and they move slower.
Objects that are closer to you appear to move in the opposite direction as you and they move faster.

Question 15

What is Binocular (Retinal) Disparity?

Answer 15

Limited in effectiveness, the two eyes see the world from different angles.
The closer one of two objects is (compared to another), the greater the retinal disparity.

Question 16

What is Adjacency Principle?

Answer 16

The effectiveness of cues is a direct function of the closeness of the objects (not a cue, it is a “weighting factor”).

Question 17

What is Equidistance Tendency?

Answer 17

In situations where the amount of depth cues is reduced (e.g., in dim light conditions), we tend to perceive objects as if they were equidistant (at the same distance) (not a cue, it is a constant bias).

Question 18

What is the size-distance invariance formula?

Answer 18

S’ = K(0D’)
S’ = perceived size
K = a constant (never changes)
0 = retinal image size (angular size)
D’ = perceived distance

Question 19

Emmert’s Law of Afterimages

Answer 19

On Desk (Close): S’ = K(0D’) (S’ and D’ are small)
On Board (Far): S’ = K(0D’) (S’ and D’ are large)

Question 20

The Ames Room

Answer 20

On Right Side (Close): S’ = K(0D’) (S’ and 0 are large)
On Left Side (Far): S’ = K(0D’) (S’ and 0 are small)

Question 21

Size Constancy

Answer 21

Close: S’ = K(0D’) (0 is large and D’ is small)
Far: S’ = K(0D’) (D’ is large and 0 is small)

Question 22

Moon Illusion

Answer 22

Overhead: S’ = K(0D’) (S’ and D’ are small)
Horizon: S’ = K(0D’) (S’ and D’ are large)

Question 23

What is the Apparent-Distance Theory?

Answer 23

Horizon moon is surrounded by depth cues while moon higher in the sky has none.

Question 24

What is the Angular Size-Contrast Theory?

Answer 24

Moon appears smaller when surrounded by larger objects. Thus , the large expanse of the sky makes it appear smaller.