Object recognition II Flashcards Preview

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Flashcards in Object recognition II Deck (8)
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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?


Biederman on viewpoint dependent recognition

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


Ullmans model

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


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


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.


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


IT neurons

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


types of features

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