1. Gestalt psychology and CV 1 Computer Vision Seminar 08/09 CSE 590CV University of Washington

2. Gestalt psychology and CV 2 Gestalt school of psychology ● School of though founded by Max Wertheimer, Wolfgang Kohler, and Kurt Koffka. ● Conceives human perception as a whole: – Reaction to structuralism. ● Original observation: phi phenomenon.

3. Gestalt psychology and CV 3 An interesting example ● The dog is not recognized through its parts but perceived as a whole.

4. Gestalt psychology and CV 4 Law of Pragnanz ● Our observations are organized as the simplest form possible.

5. Gestalt psychology and CV 5 Gestalt laws (I) ● The law of closure: ● The law of similarity:

6. Gestalt psychology and CV 6 Gestalt laws (II) ● Law of proximity: ● Law of symetry:

7. Gestalt psychology and CV 7 Gestalt laws (III) ● Law of continuity: ● Law of past experience:

8. Gestalt psychology and CV 8 Collaboration of Gestalt laws ● The grouping laws collaborate to build larger objects.

9. Gestalt psychology and CV 9 Conflicts of Gestalt laws (I) ● What happens when two grouping laws act simultaneously on the same elements. – There is no conflict. – One law wins and inhibites the other. – A conflict exists between the two laws.

10. Gestalt psychology and CV 1010 Conflicts of Gestalt laws (II) ● No conflict between laws.

11. Gestalt psychology and CV 1 Conflicts of Gestalt laws (III) ● Masking: One grouping law “wins”. – Masking by embedment in a texture. – Masking by addition.

12. Gestalt psychology and CV 1212 Conflicts of Gestalt laws (IV) ● Masking: One grouping law “wins. – Masking by substraction.

13. Gestalt psychology and CV 1313 Conflicts of Gestalt laws (V) ● Conflict between laws:

14. Gestalt psychology and CV 1414 Gestalt psychology and CS ● Web or user interface design:

15. Gestalt psychology and CV 1515 ● Gestalt psychology is descriptive. How can we derive quantitative theories? – Build CV applications that emulate human vision. ● Sarkar and Boyer proposed a classificatory structure for perceptual organization through Gestalt laws: – Signal level, primitive level, structural level and assembly level.

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