Object recognition II Flashcards Preview

PS3012 Perception > Object recognition II > Flashcards

Flashcards in Object recognition II Deck (8)
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1

Biedermann model

Proposed that we recognize objects by components, goons (geometric shapes)
critics are: how is it possible to distinguish between objects of similar shape
what are the brains mechanisms and where are the goons located?

2

Biederman on viewpoint dependent recognition

object recognition is affected by viewpoint, research shows that objects seen in less familiar viewpoints are less recognized

3

Ullmans model

explains how images/objects are segmented and how they are categorized based on visual representations (hierarchically organized)

4

Basic features of the model

highly informative pictorial fragments that are hierarchal organized
a feature is informative when it reduces uncertainty of the objects category.

informative features: need distinction and frequency

5

feature hierarchies

help to generalize objects
atomic fragments: lines, edges, corners
bottom up: incomplete information about the object
top-down segmentation: groups together different fragments and then classify it as a certain object.

6

Summary of Ullmans model

A hierarchy of abstract features continuously extracted from examples. they are usually very class-specific, non generic, and learned based on usefulness.
pros: can extract known facts of object
cons: takes a huge amount of extracting fragments

7

IT neurons

respond to pictorial objects preferentially but are not highly selective. Size and color can change.

8

types of features

low: generic and correlate directly with picture
mid: allows generalization across categories
high: very specific to a class: e.g. fruits