perception ii: scene analysis9.00/handouts/5perception2.pdf · visual and auditory scene analysis...
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![Page 1: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/1.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
1
Perception II: Scene Analysis
Scene Analysis
• Visual scene analysis:• World: 3D Objects arranged in 3D space• Optical projection: Objects, background
shmooshed together in 2D array of pixels.• Visual perception: Recover the objects
(which patches belong together), arrangements.
![Page 2: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/2.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
2
The Gestalt Laws of Grouping
The Gestalt Law of “Common Fate”
![Page 3: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/3.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
3
Figure-Ground Segregation
Illusory Contours
![Page 4: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/4.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
4
![Page 5: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/5.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
5
Top-Down Influences on Scene Analysis
The Problem of ShapeRecogniton
![Page 6: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/6.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
6
Three Better Theories of Shape Recognition
1. Multiple templates2. Mental transformations (imagery)3. Object-centered reference frames (geons)
Visual Frames of Reference (Coordinate Systems)
• Viewer-centered frame: X aligned with retinal left-right axis; Y aligned with retinal up-down axis; Z aligned with line of sight
• Object-centered frame: X aligned with an axis of the object: elongation, symmetry, intrinsic front-back. Other axes at right angles to x.
![Page 7: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/7.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
7
The problem with using a viewer-centered reference frame:
The advantageof using anobject-centeredreference frame:
The Effects of Reference Frames on Shape Perception:Effects of the Up-Down Axis:
Sometimes the Brain aligns Reference Frames with Objects,
not just the vertical axis:
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9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
8
Geons:
Testing the Three Theories(Tarr & Pinker, 1989, 1990)
• If people use object-centered representations, they should recognize an object equally well at all orientations
• If people use mental rotation, they should take longer for objects that are more tilted
• If people use multiple templates, they should take longer for orientations they haven’t seen before
![Page 9: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/9.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
9
Asymmetrical objects are mentallyrotated:
Symmetricalobjects are matchedin an object-centeredreference frame:
Train at some orientations, test at others:
People are faster with orientations they have been
trained on:
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9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
10
Visual and Auditory Scene Analysis
• Visual scene analysis:– World: 3D Objects arranged in 3D
space– Optical projection: Objects, background
shmooshed together in 2D array of pixels.
– Visual perception: Recover the objects (which patches belong together), arrangements.
Auditory Scene Analysis
• World: Things making noise (sound sources) each produces a set of frequencies.
Auditory Scene Analysis
• World: Things making noise (sound sources) each produces a set of frequencies.
• Wave superposition: all frequenciesshmooshed together in complex waveform.
![Page 11: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/11.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
11
Auditory Scene Analysis:
• World: Things making noise (sound sources) each produces a set of frequencies.
• Wave superposition: all frequenciesshmooshed together in complex waveform.
• Auditory perception: Recover thesoundmakers (which frequencies belong together), arrangement.
Scene Analysis, continued• Frequency analysis by the ear and brain.
![Page 12: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/12.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
12
Psychophysics of Sound:Frequency is perceived as pitch
time à
frequency
How Auditory Scene analysis is similar to Visual Scene Analysis:• Space in vision = frequency X time in
audition. • Object in vision = sound source
(noisemaker) in audition. • Gestalt laws of auditory organization:
proximity, continuation, common fate (motion).
Auditory Streaming
A A A A
B B
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9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
13
Gestalt laws reflect physical constraints:
• In vision, matter is cohesive and bounded: parts of an object stick and move together
• In audition, soundmakers have resonancesand nonzero mass: they can’t change pitch instantaneously
Simultaneous & Sequential Grouping
Gestalt Continuity in AuditonAuditory Scene Analysis &
Music
![Page 14: Perception II: Scene Analysis9.00/handouts/5perception2.pdf · Visual and Auditory Scene Analysis • Visual scene analysis: –World: 3 D Objects arranged in 3D space –Optical](https://reader034.vdocuments.site/reader034/viewer/2022042420/5f36bdd6bcf9b84f812844f9/html5/thumbnails/14.jpg)
9.00 Introduction to PsychologyProfessor S. Pinker
Week 5, Lecture 2: Visual and Auditory Scene Analysis
14