Perception
Download
1 / 26

Perception - PowerPoint PPT Presentation


  • 85 Views
  • Uploaded on
  • Presentation posted in: General

Perception. Question of the Day. Why is recognizing an object so easy for humans, but so difficult for computers?. Points of Confusion. http://i.ivillage.com/E/325/Celebrities/FaceReader/FaceReaderIntro_325.jpg. http://www.apogeephoto.com/mag1-6/mag2-5mf1.jpg. Perception:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha

Download Presentation

Perception

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Perception


Question of the Day

  • Why is recognizing an object so easy for humans, but so difficult for computers?


Points of Confusion

http://i.ivillage.com/E/325/Celebrities/FaceReader/FaceReaderIntro_325.jpg

http://www.apogeephoto.com/mag1-6/mag2-5mf1.jpg


Perception:

attaching meaning to incoming sensory information

What is

this?


Figure 2-1Distal Stimuli, Proximal Stimuli, and Percepts.


Perceptual Constancies

  • Shape Constancy

    • Tendency to see an object as keeping its form despite changes in orientation.


Perceptual Constancies

  • Size Constancy

    • Tendency to view an object as constant in size despite changes in the size of the retinal image.

http://www.psychologie.tu-dresden.de/i1/kaw/diverses%20Material/www.illusionworks.com/assets/images/constancy.jpg


Perceptual Constancies

  • Illusions


Gestalt ApproachFigureGround Figure 2-2


Gestalt ApproachSubjectiveContoursFigure 2-3


Gestalt principles of Perceptual Organization

  • Proximity

http://www.sapdesignguild.org/resources/optical_illusions/images/proximity.gif


Gestalt principles of Perceptual Organization

  • Similarity

  • http://www.aber.ac.uk


http://chd.gse.gmu.edu/immersion/knowledgebase/strategies/cognitivism/gestalt/Image6.gif

not this

what most people

would see

Gestalt principles of Perceptual Organization

  • Good continuation

  • http://www.aber.ac.uk


Gestalt principles of Perceptual Organization

  • Closure

http://daphne.palomar.edu

http://www.aber.ac.uk/media/Modules/MC10220/Images/seal.gif

http://graphicdesign.spokanefalls.edu/tutorials/process/gestaltprinciples/closure/closure_a.gif


Gestalt principles of Perceptual Organization

  • Common fate


Figure 2-5

Gestalt principles of Perceptual Organization


Two Interacting Aspects of Perception

  • Bottom-up processing

    • Processing based on incoming stimuli from the environment

    • Also called data-based processing

  • Top-down processing

    • Processing based on the perceiver’s previous knowledge

    • Also called knowledge-based processing

http://jurmo.us/log/wp-content/uploads/2007/04/topdownbottomup.jpg


Bottom-Up Processes

The number “4” from the check is compared to a list of stored templates.

Template

matching


Bottom-Up Processes

Problems with Template Matching

  • Large number of stored templates needed

  • How are new templates made?

  • An object can be “more or less” like the template

    • We can recognize many variations of a template


Bottom-Up Processes

Figure 2-8


Bottom-Up Processes

Featural Analysis

features (“parts”) of a stimulus are recognized by feature detectors and added together to help us perceive an object

  • Lines or edges

  • Geons

  • Phonemes

  • Parts of a face (eyes, nose…)


Featural Analysis

Geons


Figure 2-14 A depiction of Selfridge’s (1959) Pandemonium model.

Featural

Analysis

Letter

detection


Bottom-Up Processes

Featural Analysis

Feature Properties

  • Detectors can respond at different intensities

  • Connections between detectors can have different strengths

  • It is possible to change what a detector will respond to


Bottom-Up Processes

Prototype Matching


Bottom-Up Processes

Prototype Matching

http://www.palm.com


ad
  • Login