LECTURE 4- OBJECT RECOGNITION

Question 1

What is object recognition?

Answer 1

The process of identifying objects that surround us.

Question 2

What is perception?

Answer 2

The process of discovering what is present in the world and where it is, based on sensory input.

Question 3

Why is perceptual organization necessary?

Answer 3

Retinal images are disorganized, like a mosaic, and need to be structured for object recognition.

Question 4

What are the key components of perceptual organization?

Answer 4

Figure-ground segregation and grouping elements into patterns or objects.

Question 5

What is figure-ground segregation?

Answer 5

Identifying one object as the figure while the rest forms the background.

Question 6

What are bottom-up processes?

Answer 6

Stimulus-driven processes independent of cognitive factors.

Question 7

What are top-down processes?

Answer 7

Cognition-driven processes influenced by prior knowledge.

Question 8

What is Gestalt psychology?

Answer 8

A school of thought emphasizing perception as a whole, rather than as individual components.

Question 9

What are the “laws” of perceptual organization?

Answer 9

Principles like similarity, proximity, closure, and continuity, guiding how elements are grouped.

Question 10

What is the principle of similarity?

Answer 10

Similar elements are grouped together perceptually.

Question 11

What is the principle of proximity?

Answer 11

Elements close to one another are grouped together.

Question 12

What is the principle of closure?

Answer 12

The mind completes incomplete shapes to form a whole.

Question 13

What is the principle of continuity?

Answer 13

Smooth curves or continuous patterns are grouped together.

Question 14

What is the vase-face illusion?

Answer 14

A classic example of figure-ground segregation where the figure alternates between a vase and two faces.

Question 15

What are natural scene statistics?

Answer 15

Physical regularities in the environment, like edges being vertical or horizontal, aiding perceptual processing.

Question 16

What is the “light from above” assumption?

Answer 16

The brain assumes light sources come from above, influencing perception of depth and shadows.

Question 17

What is Marr’s theory of object recognition?

Answer 17

A computational model involving stages like primal sketch, 2.5D sketch, and 3D model to recognize objects.

Question 18

What is a primal sketch?

Answer 18

A 2D description of light intensity changes, such as edges and boundaries.

Question 19

What is a 2.5D sketch?

Answer 19

A representation of surfaces with depth and orientation based on texture, motion, and binocular disparity.

Question 20

What is a 3D sketch?

Answer 20

A view-independent description of an object’s structure used for recognition.

Question 21

What are generalized cones?

Answer 21

Basic shapes that objects can be decomposed into, forming the foundation of Marr’s structuralist approach.

Question 22

What is Biederman’s theory of object recognition?

Answer 22

It extends Marr’s model by introducing geons, or 3D components, as building blocks of objects.

Question 23

What are geons?

Answer 23

Simple, non-accidental features that are invariant across views and form the basis of object recognition.

Question 24

What is the difference between recoverable and non-recoverable degraded objects?

Answer 24

Objects can be recognized if their non-accidental features are preserved.

Question 25

What is viewpoint independence?

Answer 25

The ability to recognize objects regardless of the angle of view, as proposed by structuralist theories.

Question 26

What is viewpoint dependence?

Answer 26

Recognition performance varies with changes in the object’s orientation or angle.

Question 27

What is agnosia?

Answer 27

A neurological condition where object recognition is impaired despite intact vision.

Question 28

What are the two types of agnosia?

Answer 28

Apperceptive agnosia (perceptual deficit) and associative agnosia (interpretation deficit).

Question 29

What brain area is affected in apperceptive agnosia?

Answer 29

The posterior right hemisphere.

Question 30

What brain area is affected in associative agnosia?

Answer 30

The bilateral occipitotemporal junction.

Question 31

What is prosopagnosia?

Answer 31

The inability to recognize faces, often due to damage in the fusiform gyrus.

Question 32

What is the Thatcher illusion?

Answer 32

A phenomenon where inverted faces appear normal, highlighting the brain’s specialization for upright faces.

Question 33

What did Kanwisher et al. (1997) discover?

Answer 33

Specialized brain areas, like the fusiform gyrus, are activated by faces.

Question 34

What is visual imagery?

Answer 34

“Seeing with the mind’s eye,” or forming mental images without direct sensory input.

Question 35

What happens in mental rotation tasks?

Answer 35

Response times increase with the angular disparity between objects, indicating mental simulation of rotation.

Question 36

How are visual perception and visual imagery related?

Answer 36

They rely on similar brain mechanisms, as shown by cases like cerebral achromatopsia.

Question 37

What are the key stages in object recognition discussed in the lecture?

Answer 37

Perceptual organization, object recognition, brain systems, face recognition, and visual imagery.

Question 38

What is the significance of structuralist theories in object recognition?

Answer 38

They provide a framework for understanding how objects are broken down and reconstructed for recognition.

Question 39

What is the main challenge in object recognition?

Answer 39

Structuring disorganized retinal images into recognizable objects through perceptual processes.