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Gestalt Principles of Perception then Introduction to Object Perception

Gestalt Principles of Perception then Introduction to Object Perception

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Gestalt Principles of Perception then Introduction to Object Perception

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  1. Gestalt Principles of PerceptionthenIntroduction to Object Perception Psychology 355: Cognitive PsychologyInstructor: John Miyamoto04/09/2014: Lecture 02-3 This Powerpoint presentation may contain macros that were used to create the slides. The macros aren’t needed to view the slides. If necessary, you can disable the macros without any change to the presentation.

  2. Outline • Yesterday: • Inverse Projection Problem • Perceptual Heuristics • Gestalt principles of perception • Object perceptionRecognition-by-Components (RBC) theory of object perception # Psych 355, Miyamoto, Spr '14

  3. The Gestalt Approach • Emerged in early 20th century in response to structuralism.(Structuralism claimed that perception was bottom up – it was built up from simple, atomistic sensations.) • “The whole is greater than the sum of the parts” – Anti-Atomism • Basic question of the Gestalt approach to perception: What principles govern the grouping of the components of a perceptual stimulus into an object or organized group of objects? • Gestalt principles are sometimes called heuristics—Gestalt principles provide “best guesses” about the stimulus object. Principle of Similarity Psych 355, Miyamoto, Spr '14

  4. Gestalt Principle of Similarity • Similar things are grouped together. • Similarity in lightness, shape, color, size, and orientation cause grouping. a aaaaaa a b c d e f gb bbbbbb a b c d e f gc cccccc a b c d e f gd dddddd a b c d e f ge eeeeee a b c d e f gf ffffff a b c d e f gggggggg a b c d e f g (looks like rows)(looks like columns) Principle of Good Continuation Psych 355, Miyamoto, Spr '14

  5. Gestalt Principle of Good Continuation • Connected points result in smoothly curving lines. • Points are seen as they belong together. • Lines follows smooth path. Figure-Ground Principle Psych 355, Miyamoto, Spr '14

  6. Figure-Ground Principle and the Principle of Smallness • Figure/ground Principle – ambiguous figureThe famous faces/vase figure. Face is Face is background foreground Principle of Smallness implies that we should see vases on the left and faces on the right Escher Print #1 Psych 355, Miyamoto, Spr '14

  7. Figure-Ground Example • Downloaded from http://www.worldofescher.com/gallery/A41L.html • MauritsCornelis EscherDutch graphics artist1898 - 1972 • Figure-ground problem:Separation of objectfrom background Escher Print #2 Psych 355, Miyamoto, Spr '14

  8. Another Figure-Ground Example • Downloaded from http://www.worldofescher.com/gallery/A11L.html Principle of Common Fate Psych 355, Miyamoto, Spr '14

  9. Gestalt Principle: Common Fate • Principle of common fate: Things that are moving in the same direction (at the same speed) appear to be grouped together. • Go to website – look at it: • http://tepserver.ucsd.edu/~jlevin/gp/time-example-common-fate/This is a nice demonstration of the common fate principle. The groups of lines or shapes are only visible as a group when they are moving together. • WARNING: The preceding demonstration requires a browser that has JAVA activated. I don’t understand the technicalities, but there aredangers (computer viruses) associated with the use of JAVA. • If preceding example is not available, see examples on next page P 355, Miyamoto, Winter '09 9 Examples of Gestalt Principle in Visual Design Psych 355, Miyamoto, Spr '14

  10. OK – Demos of Common Fate Principle • Good http://dragon.uml.edu/psych/commfate.html • Very good, Michael Bach http://www.michaelbach.de/ot/col-equilu/index.html • Nice doggie • Very nice demo http://art.nmu.edu/groups/cognates/wiki/f157d/Common_Fate.html • OK https://www.youtube.com/watch?v=nuH6dIcgaoU Examples of Gestalt Principle in Visual Design Psych 355, Miyamoto, Spr '14

  11. Examples of Gestalt Principles in the World of Visual Design Principle of similarity implies that we see the three left figures as a group. Thus the right figure is an exception (anomaly) so it stands out. Principle of continuation: We "see" the motion of the leaf. Principle of Figure/Ground Principle of Simplicity Summary: Evidence for Gestalt Principle of Perception - END Psych 355, Miyamoto, Spr '14

  12. Summary – Evidence for Gestalt Principles of Perception • Phenomenological support • Experimental evidence – image segmentation(Not discussed in this lecture) • Gestalt laws are perceptual heuristics • Gestalt laws help explain how perception solves the inverse projection problem (inferring a specific reality from ambiguous inputs). • Important in the theory of object perception (next topic) Object Recognition – Recognition-By-Components Theory Psych 355, Miyamoto, Spr '14

  13. Recognition-By-Components (RBC) Theory of Object Perception • Examples of object perception • Biederman’s Recognition-By-Components (RBC) Theory of Object Perception • Non-accidental features of objects • Geons • Priming – What is it? • Experimental evidence for the psychological reality of geons.The experiment uses a priming methodology. Tomorrow Example of Object Perception – Furnished Room Psych 355, Miyamoto, Spr '14

  14. Some Examples of Object Perception More Examples of Object Perception – A Forest Scene Psych 355, Miyamoto, Spr '14

  15. More Examples of Object Perception The Problem of Object Perception Psych 355, Miyamoto, Spr '14

  16. The Problem of Object Perception • How do humans impose a perceptual organization on a highly complex stimulus input? • At any given moment, we are detecting huge numbers of features in the visual environment. • What we perceive is a smaller number of objects that are arranged in a meaningful scene. • How do we know which features are part of the same object and which features are parts of different objects? The Recognition-By-Components Theory of Object Perception Psych 355, Miyamoto, Spr '14

  17. Biederman's Recognition-by-Components (RBC) Theory of Object Recognition • Geons ("geometric ions") • Biederman, I.  (1987).  Recognition-by-Components:  A Theory of Human Image Understanding.  Psychological Review, 94, 115-147. • A geon is a visual pattern that typically indicates a part of an object. Geons Objects Partial List of Geons Psych 355, Miyamoto, Spr '14

  18. Biederman (1987), pp. 122: Partial list of "geons" (elementary shapes that the visual system detects during object and scene recognition) • Think of features and geons as part of a hierarchy: Atom ~ Feature Molecule ~ Geon Material ~ Object physics perception Principle of Non-Accidentalness Psych 355, Miyamoto, Spr '14

  19. Principle of Non-Accidentalness(due to Lowe): Objects typically produce systematic relations between perceptual features. Geons are elementary shapes that exhibit such non-accidental features. Perceptions of objects are built from component geons. Non-Accidental Features of a Brick and Cylinder Psych 355, Miyamoto, Spr '14

  20. Some Non-Accidental Features of a Brick & a Cylinder InnerY Vertex Two tangent Y vertices(Occluding edge tangentat vertex to discontinuous edge) Threeparalleledges Three outerarrow vertices Curved edges Two paralleledges • According to Biederman, "geons" are a small set of elementary shapes that exhibit such non-accidental features. Perceptions of objects are built from component geons. (Biederman (1987), pp. 121.) Return to Preceding List of Geons Psych 355, Miyamoto, Spr '14

  21. Biederman (1987), pp. 122: Partial list of "geons" (elementary shapes that the visual system detects during object and scene recognition) • Think of features and geons as part of a hierarchy: Atom ~ Feature Molecule ~ Geon Material ~ Object physics perception Return to Image of Furnished Room – What are the Non-Accidental Features Psych 355, Miyamoto, Spr '14

  22. Some Examples of Object Perception • Can you see any examples of non-accidental features? • What are examples of geons in this image? Return to the Forest Scene Psych 355, Miyamoto, Spr '14

  23. This image also has many examples of non-accidental features & geons. The RBC Theory is Both Top Down & Bottom Up Psych 355, Miyamoto, Spr '14

  24. RBC Theory – Both Top-Down & Bottom Up • Goldstein textbook uses RBC theory as an example of bottom up processing, ..... but both top down & bottom up are actually working togetherin object recognition. • RBC Theory uses Gestalt principles to build perceptional "geons," which are intermediate building blocks in object perception. Schematic Diagram Showing the Stages of Processing in Object Perception Psych 355, Miyamoto, Spr '14

  25. Wednesday, April 09, 2014: The Lecture Ended Here Psych 355, Miyamoto, Spr '14

  26. Stages in Object Perception (Biederman, 1987) Elementary feature analysis Detect Non-Accidental Features Edge Extraction Parsing at Regions of Concavity Detection of Non-Accidental Properties Identification of geons Determination ofComponents Integration of geons into objects Matching of Components to Object Representations Identification of objects Object Identification What Kind of Evidence Would Demonstrate the Existence of Geons? Psych 355, Miyamoto, Spr '14

  27. Can We Find Evidence for Geons? • Geons – a hypothesized intermediate representation in the construction of object perception. • Can we find behavioral evidence that geons exist in human object perception? • Tomorrow: We will discuss evidence for geons from a priming experiment. END Psych 355, Miyamoto, Spr '14