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Chapter 3 _ Object Recognition + 이선정
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Gestaltist appoach
Law of Pragnanz
“of several geometrically possible organisation that one will actually occur which possess the best, simplest and most stable shape “ (Koffka, 1935)
Perceptual Organization Perceptual Organization
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e
Gestaltist appoach
- a. the law of proximity - b. the law of similarity
- c. the law of continuation
- d. the law of closure
- e. the law of common fate
a b
c d
Perceptual Organization Perceptual Organization
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Gestaltist approach
- figure- ground segregation
- a) Homogeneous display b) Heterogeneous display - grouping of perceptual elements occurs early in visual processing
Perceptual Organization Perceptual Organization
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Gestaltist approach – Contray evidence
Perceptual Organization Perceptual Organization
a
b
c
Upright Upside down
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Primal sketch : this provide a 2-dimensional description of the main light – intensity change in the visual input, including
2 ½ - D Sketch : this incorporate a description of the depth and orientation of visible surface, making use of information provided by hading texture, motion, binocular disparity, and so on
3 - D Model representation : 3 – dimensionally the way that is independent of objects and their relative positions in a way that is independent of the observer’s view point
Theories of Objection Recognition Theories of Objection Recognition
Marr’s computational theory
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Theories of Objection Recognition Theories of Objection Recognition
Biederman’s recognition by components theory
- consisting of basic shape or components known as “geon” (36 개 )
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Theories of Objection Recognition Theories of Objection Recognition
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Theories of Objection Recognition Theories of Objection Recognition
Five invariant properties of edges
- culvature – point on a curve
- parallel – sets of points in parallel
- cotermination – edges terminating at a common point
- symmety - versus asymmetry
- collinearity – points sharing a common line
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Objection Recognition Objection Recognition
Viewpoint _ dependent & viewpoint _ invariant theories
- viewpoint invariant theory ease of object recognition is not affect by observer’s view point
- viewpoint dependent theory change in viewpoint reduce the speed and of accuracy of object recognition
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Brain System in Object RecognitionBrain System in Object Recognition
Visual agnosia
- Apperceptive agnosia object recognition is impaired because of deficits in perceptual processing - Associative agnosia Perceptual processes are essentially intact object recogntion is impaired partly or mainly
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Brain System in Object RecognitionBrain System in Object Recognition
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Brain System in Object RecognitionBrain System in Object Recognition
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Face RecognitionFace Recognition
Bruce and Young’s model
-Structural encoding
-Expression anaysis
-Facial speech analysis
-Directed visual processing
-Face recognition unit
-Person identify nodes
-Name generation
-Cognitive system
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Face RecognitionFace Recognition
Interactive activation and competition model
WRUs = word recognition Units
FRUs = face recognition Units
NRUs = name recognition Unit s
PRUs = Person recognition nodes WRUs = semantic information Unit
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Face RecognitionFace Recognition
Are faces special ? Yes! - something special about face recognition
1) Holistic analysis 2) Analysis by parts
Are faces special ? No! - why face appear special ?
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Visual imageryVisual imagery
“Seeing with the mind eye”
-Mental imagery has been that it is very similar to perception
-Why do we not confuse images and perception? Mental scanning - mental rotation
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Thank You
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