1. Perspective!!! Igor Juricevic & John M. Kennedy

2. Outline Basics of perspective –What is perspective? –Why study perspective? –Why study perspective pictures? Experiments 1-4 –The ART theory –Is the ART theory general across observer position? –Is the ART theory general across eye-height? –Is the ART theory general across object orientation?

3. What is perspective? Leonardo –Perspective is nothing else than seeing a place or objects behind a plane of glass, quite transparent, on the surface of which the objects behind the glass are to be drawn.

4. What is perspective? from Taylor (1719)

5. What is perspective?

6. Why study perspective? Perspective is the basic geometry of the visual system –Determines the information available to the visual system

7. Why study perspective pictures? Reason 1: explain picture perception Since the Renaissance… paradoxes concerning picture perception have plagued the consciousness of mankind Explanations by: –Leonardo da Vinci –Albert Einstein –other guys… –have all FAILED!!!

8. Reason 1: explain picture perception

12. Why study perspective pictures? Reason 1: explain picture perception Reason 2: explain spatial perception

13. The assumption –There is nothing special about picture perception –Picture Perception = Everyday Perception So, a theory that can account for picture perception will account for everyday perception as well But… –Why not just study Everyday Perception?

14. Reason 2: explain spatial perception Why not just study everyday perception? Newtonian Physics vs. Einstein’s Physics

15. Reason 2: explain spatial perception Why not just study everyday perception? Everyday perception will give you a “Newtonian Physics” theory of vision Picture perception may give you an “Einstein’s Physics” theory of vision –Why? Because you can put people in novel situations –i.e., you can have the observer at the wrong vantage point

16. The ART theory

17. Experiment 1

24. Observer is: TOO FAR Observer is: TOO CLOSE Observer is: JUST RIGHT

25. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: TOO FAR

26. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: TOO FAR

27. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: TOO FAR

28. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: JUST RIGHT

29. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: TOO CLOSE

30. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: TOO CLOSE

31. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110) Observer is: TOO CLOSE

32. The ART theory The “Angles and Ratios Together” theory Angles –“Angle from the Normal” Ratios –Visual Angle ratios Together –Together

33. The ART theory D O C B A

34. The ART theory: Angle from the Normal D O C B A

35. The ART theory: Visual Angle Ratio (Side/Bottom) D O C B A

36. The ART theory The “ART Theory Ranges”

37. The ART theory Able to account for Experiment 1… Can it generalize to other situations? Like…

38. The ART theory Changes in observer position?

39. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

40. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

41. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

42. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

43. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

44. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

45. Compressed (Average Response <90) Perspective Constancy (Average Response 90-110) Elongated (Average Response >110)

49. The ART theory Changes in observer position? YES

50. The ART theory Changes in eye-height?

51. High Mid Low

55. The ART theory Changes in eye-height? YES

56. The ART theory Changes in orientation? Experiments 1, 2, and 3Experiment 4

57. Observer is: TOO FAR

58. Observer is: TOO FAR

59. Observer is: TOO FAR

60. Observer is: JUST RIGHT

61. Observer is: TOO CLOSE

62. Observer is: TOO CLOSE

63. Observer is: TOO CLOSE

67. The ART theory Changes in orientation? Experiments 1, 2, and 3Experiment 4 MAYBE

68. Conclusions The ART theory begins to explain some of the paradoxes of picture perception The ART theory can be applied to perception of the real world (i.e., “Everyday Perception”) May need to add factors to ART theory to deal with orientation

69. Thank you.