Visual Perception - Principles

Question 0

What are the four Gestalt principles?

Answer 0

Figure ground, closure, proximity and similarity

Question 1

Define: gestalt principles

Answer 1

Processes in which we organise parts of a scene by grouping them to perceive a whole, complete picture

Question 2

What is figure ground and provide an example of it?

Answer 2

Organising an image into a figure (foreground) which stands out from the ground (background)
Eg. Stop sign, the white writing is the figure and the red is the ground

Question 3

How do we separate figure and ground and what does this thing belong to the figure or the ground?

Answer 3

Contour - separation between figure and ground

Belongs to the figure

Question 4

What can form when the contour can’t be easily defined/belongs to both figure and ground?

Answer 4

Camouflage, ambiguous/ reversible figured

Question 5

Define: closure,

Provide an example

Answer 5

Tendency to close up gaps in a visual image to perceive them as a whole.
Eg stencils, IBM logo

Question 6

Define: similarity and provide an example

Answer 6

Tendency to perceive similar parts of an image as being grouped together.
Eg. Uniforms, ishihara tests for colourblindness

Question 7

Define: proximity and provide an example

Answer 7

Tendency to perceive parts of an image that are close together as being grouped together.
Eg. Constellations, where people stand at recess

Question 8

Define: depth perception

Answer 8

Ability to use depth cues to estimate the distance of objects and to perceive the world as 3d

Question 9

Define: depth cues

Answer 9

Cues which allow us to predict an objects location in space.

Question 10

Name the monocular (state which are pictorial cues) and binocular depth cues

Answer 10

Binocular: convergence, retinal disparity
Monocular: accommodation, pictorial ➡️ linear perspective, interposition, texture gradient, relative size, height in the visual field

Question 11

Define: pictorial cues

Answer 11

Visual perception cues which can be presented 2 dimensionally

Question 12

Convergence: define, what do changes in tension mean, only necessary within how many metres? Example

Answer 12

Judging an objects location in space from the amount the eyes turn inwards.
Greater tension: closer the object, less tension: further away
Only works within 6m
Eg. If you move a pen close to your face your eyes will turn in

Question 13

Define: retinal disparity, example

Answer 13

The slight difference between the two visual images on the two retinae (because of the 6-7cm distance between the eyes); objects location predicted by how difficult it is to combine the two images
Eg. Hold a pen in front of you closely using one eye at a time, see how much it moves

Question 14

Define: accommodation,

What happens to lens when it is being viewed from closer and from far away?

Answer 14

The automatic adjustment of lenses to accommodate an image on the retina. allows us to estimate where an object is located in space by how much the lens bulges or elongates
Closer ➡️ bulges
Far away ➡️ lens elongates

Question 15

Define: linear perspective, example

Answer 15

How parallel lines appear to converge when they move away

Eg. Train tracks, a road

Question 16

Define: interposition, example

Answer 16

When one object partially covers another, the partially covered object is perceived as further away and vice versa and vice versa
Eg if two runners are running one after the other, the one that is covered is further away

Question 17

Define: texture gradient, example

Answer 17

How patterned/textured objects appear to lose detail as it recedes into the distance
Eg, brick road

Question 18

Define: relative size, example

Answer 18

If two objects are the same size, then the object that rogues the larger image on the retina will be perceived as closest
Eg. From a front view, looking at two people standing 10m apart

Question 19

Define: height in the visual field

Example

Answer 19

How objects which are near the horizon are perceived to be further away and vice versa
Eg. An air balloon in the air appears closer than it is if it’s near the horizon

Question 20

Define: perceptual constancy

Answer 20

Tendency perceive objects as being the stable, constant and unchanging, regardless of the context in which it was viewed which could change the image cast on the retina.

Question 21

What are the 3 perceptual constancies?

Answer 21

Size, shape and brightness

Question 22

Define: size constancy, example

Answer 22

An objects actual size remains the same regardless of what image appears on the retinae (caused by viewing from different distances), inferred from past experience
Eg. Train in distance is the same size as train near you

Question 23

Define: shape constancy, example

Answer 23

An objects shape is the same regardless of what image appears on the retinae, caused by viewing from different angles
Eg. Looking at a trophy from different angles, it still remains the same shape

Question 24

Define: brightness constancy, example

Answer 24

An objects brightness is the same regardless of what image appears on the retinae, caused by changes in amount of light cast on it Eg. Wall remains the same colour in the middle of the night as it does in the middle of the day