Object Recognition Flashcards Preview

Cogniton In Clinical Contexts > Object Recognition > Flashcards

Flashcards in Object Recognition Deck (17):
1

Theories of object recognition

Template matching
Feature analysis theory
Recognition by components theory
View centred approach

2

Template matching theory

First explanation
Inadequate
Compare stimulus with a set of templates or patterns in your memory, works for computers but not humans as if a letter is different from the template, it won't work
Only works for isolated letters, numbers and simple objects

3

Feature analysis theory

Each visual stimulus is composed of a number of characteristics - each characteristic is a distinctive feature
When you look at a letter your visual system notes the presence/absence of various features then compares it with your memory
Problems include: shouldn't only list features, should describe relationship among features, 2 letters may have same features, only explains simple objects and letters

4

Recognition by components theory

Explains how humans recognise 3D shapes
Objects are represented as an arrangement of simple shapes called geons - combined to form objects
Problems - requires modifications as people recognise objects less quickly when objects are seen from a weird view

5

View centred approach

Store a small number of views of 3D objects, rather than just one view
If we see it from an unusual view we will have to rotate it till it matches a view stored
Can make errors

6

Organisation in the visual perception

Visual system imposes organisation on the complicated world

7

Gestalt principles

Believes human organise what they see e.g. Patterns not just random objects
Organisation means some things stand out, some go in the background

8

Perception

Ability to extract meaning from sensory input
Made up of previous knowledge about what to expect

9

Visual System

Our brain receives sensory info allowing us to perceive an object
Visual info goes through occipital lobe

10

Distal stimulus

Object in the environment

11

Proximal stimulus

Info registered on sensory receptors
Can recognise objects presented for 1/10 of a second

12

Illusionary contours

Can see edges even if they aren't present, we fill in blanks which leads to perceptual error

13

Limitations of visual system

Blind spot in each eye, gaps get filled in, visual system filters things out

14

Bottom up processing

Characteristics of the shape

15

Top down processing

Expectations of where the shape is
E.g. Expect to find a shape in certain places
This process is strong when stimuli is ambiguous

16

Reading

Word superiority effect - can identify a single letter more accurately and quickly when in a meaningful word than when it's alone/in a non word
Context speeds word reading up

17

Errors in object recognition

Change blindness - inability to detect changes in an object or scene
Inattentional blindness - paying attention to some events so missing an unexpected event