1. CPSC 599.28/601.28 Cognitive Perspective Sheelagh Carpendale

2. Introduction Supporting visual thinking –developing representations –comprehension some vision perception basics attention colour depth

3. References Colin Ware. (2004) Information Visualization: Perception for Design. Morgan Kaufmann. Maureen Stone. (2003) A field guide to digital color. AK Peters S. S. Stevens. (1961) The Psychophysics of Sensory Function. Sensory Communication, MIT Press, pp 1-33. William S. Cleveland, Robert McGill. (1984) Graphical Perception: Theory, Experimentation and the Application to the Development of Graphical Models. J. Am. Stat. Assoc. 79:387, pp. 531-554. Leland Wilkinson. (1993) Comment on Cleveland. Journal of Computational and Graphical Statistics, 2, pp. 355-360. Bernice E. Rogowitz and Lloyd A. Treinish. (1996) How Not to Lie with Visualization. Computers In Physics 10(3), pp 268-273. http://www.research.ibm.com/dx/proceedings/pravda/truevis.ht m http://www.research.ibm.com/dx/proceedings/pravda/truevis.ht m C. Brewer. (1999) Color use guidelines for data representation. http://www.personal.psu.edu/faculty/c/a/cab38/ColorSch/ASApaper.ht ml http://www.personal.psu.edu/faculty/c/a/cab38/ColorSch/ASApaper.ht ml

4. Foveal vision size of a thumbnail at arms length Corresponds to a small high resolution area on the retina http://www.cs.nyu.edu/~yap/visual/home/proj/foveation.html

5. Foveal vision http://psy.ucsd.edu/~sanstis/SABlur.html

6. Foveal vision http://psy.ucsd.edu/~sanstis/SABlur.html

7. Field of View Useful field of view varies with task low character density - as wide as 15 o high character density - as narrow as 1 o to 4 o

8. Foveal vision http://psy.ucsd.edu/~sanstis/SABlur.html

9. Saccades Fovea gives small high resolution images Saccades do rapid scanning Brain assembles Vision perceived as continuous http://vision.arc.nasa.gov/personnel/jbm/home/projects/osa98/osa98.html

10. Eye movements Saccadic movements –eye moves rapidly from fixation to fixation –dwell period 200 to 600 msec –saccade takes 20 to 100 msec –peak velocity can be 900 deg/sec –ballistic - cannot be adjusted mid saccade –saccadic suppression - less sensitive visually during a saccade smooth-pursuit movements – ability to ‘lock-on’ to a smoothly moving object – enables head and/or body movements while maintaining visual contact convergent movements – towards - eyes converge – away - eyes diverge accommodation – new target - refocus - 200 msec – convergence and accommodation neurologically coupled

11. Affected by motion appearance motion Field of View X

12. Change Blindness some times changes are not perceived http://viscog.beckman.uiuc.edu/djs_lab/demos.html http://www.psych.ubc.ca/~rensink/ Rensink, Ronald A.; O'Regan, J. Kevin & Clark, James J. (1997), To see or not to see: the need for attention to perceive changes in scenes, Psychological Science 8 (5): 368-373. Silverman, M. & Mack, A. (2006), Priming by change blindness: When it does and does not occur, Consciousness and Cognition 15: 409-422. Simons, Daniel J. & Levin, Daniel T. (1998), Failure to detect changes to people during a real-world interaction, Psychonomic Bulletin and Review 5: 644-649.

13. Light and Objects objects reflect light luminance black paper in sunlight vs. white paper in indoor lighting conditions eyes and photometers - we see differences not absolutes (this is similar to many sensory systems)

14. Image from John MCann Image from John MCann (slide M. Stone)

15. Image from John MCann

16. Image from John MCann (slide M. Stone)

18. Human Perception and Light Difference Signaling Contrast vs. value information Light value information vs. object information. cell has normal rate light in centre excites light in surrounds inhibits

19. Consequences Hermann Grid Illusion

20. Consequences Scintillating Grid

21. Consequences Grating Induction Effect

22. Consequences Mach Banding

23. Consequences Chevreul Illusion

24. Consequences Crispening

25. Consequences Craik-Cornsweet Effect

26. Seurat: The Bathers Craik-Cornsweet Effect

27. Lightness/Brightness summary Encoding of Information in greyscale Perception may not be as expected C. Ware’s advice - often better ways to encode information than to use a greyscale The human eye is not a photometer, and should not be treated as such Understanding how the eye does work can help us avoid problems that might arise

28. Overview for Attention eye movements searching neural processing information density information coding applications

29. Reading and short term memory How many symbols can you remember? Usually about 7 7+ or - 2 short term memory as 1 o X ? & % # Q @ 9 6 $ * F

30. Pre-attentive processing 2358945739756860796752453512346534624356245762457245 6134523523523523523524351345324716498762987460329587 2358276533637872138764298769876364098721696532962413 9237462163987639871236597124593874638746988712649817 2649872165971523972356987129721653978216409871246478 3467218987639450897764398217346946496439276430987263 4287469864987597152397123976490871469876498724369812 7346987461435895321456865437

31. Pre-attentive processing X Number of distracters Response time (milliseconds) 1000 250 750 500 91263 XXX typical results pre-attentive non-pre-attentive X

32. Pre-attentive processing Features thought to be pre-attentive form –line orientation –line length –line width –line collinearity –size –curvature –spatial grouping –added marks –numerosity colour –hue –intensity spatial position –2d position –stereoscopic depth –convex/concave from shading motion –flicker –direction of motion

33. Pre-attentive processing orientation number size shape curved/straight shape

34. Pre-attentive processing value Parallelism ?? Juncture ?? convex/concave enclosure addition

35. Pre-attentive processing Colour shape

36. Pre-attentive processing Conjunction search Colour and shape

37. Pre-attentive processing generalizations which dominates seems to vary with degree of ‘separation’ adding is ‘better’ than taking away to be pre-attentive a colour needs to be ‘outside’ the boundary of the region defined by the other colours in the display

38. Position: best for all data types data type Mackinlay, Automating the Design of Graphical Presentations of Relational Information, ACM TOG 5:2, 1986

39. For quantitative data

40. Graphical Perception: Theory, Experimentation and the Application to the Development of Graphical Models. William S. Cleveland, Robert McGill, J. Am. Stat. Assoc. 79:387, pp. 531-554, 1984. Frames can increase accuracy

41. A A T D

42. A A T D Similar to Ware’s adaptation of Nakayama et al.

43. Based on visual gestalt (perception of ‘wholeness’) Descriptive rather than explanatory Proximity Similarity Continuity (connectedness) Closure Figure/ground Symmetry Common fate (things moving together) Gestalt Principles: perception

44. Based on visual gestalt (perception of ‘wholeness’) Proximity Gestalt Principles: perception x a b Information Visualization: Perception for Design. Ware, Morgan Kaufmann, 2000

45. Based on visual gestalt (perception of ‘wholeness’) ProximitySimilarity Gestalt Principles: perception

46. Continuity Gestalt Principles Information Visualization: Perception for Design. Ware, Morgan Kaufmann, 2000

47. connectedness Gestalt Principles Information Visualization: Perception for Design. Ware, Morgan Kaufmann, 2000

48. Closure Gestalt Principles

49. Closure Overrules proximity, similarity Gestalt Principles Information Visualization: Perception for Design. Ware, Morgan Kaufmann, 2000

50. Symmetry Emphasizes relationships Gestalt Principles Information Visualization: Perception for Design. Ware, Morgan Kaufmann, 2000

51. Common fate http://tepserver.ucsd.edu/~jlevin/gp/time-example-common-fate/ Gestalt Principles Information Visualization: Perception for Design. Ware, Morgan Kaufmann, 2000

52. Figure/ground Smaller components seen as objects Gestalt Principles

53. figure/ground Gestalt Principles M. C. Escher print: Study of the Regular Division of the Plane with Horsemen

54. Visual variableDimensionalitycomment Spatial positionx, y, z colour3D – colour theoryLuminance contrast needed shape2-3? unknownSize and degree of elongation and ? orientation3D – orientation of axes not independent of shape Surface texture3DNot independent of shape and colour Motion2-3?Largely unknown blink1DNot independent of motion

55. Depth Cue Theory -Monocular Static (Pictorial) -Monocular Dynamic (Moving Picture) -Binocular Task-Based Space Perception Space Perception

56. Monocular Static (Pictorial) -Linear Perspective -Texture Gradient -Size Gradient -Occlusion -Depth of Focus -Cast Shadows -Shape-from-Shading Space Perception: depth cue theory

57. The Geometry of Linear Perspective

58. Texture Gradient Convergent Lines & Size Gradient

59. Occlusion

60. Depth of Focus

61. Cast Shadows

62. Monocular Dynamic (Moving Picture) -Structure from Motion (motion parallax, kinetic depth)

63. a) Velocity Gradient, b) Velocity Field, c) Kinetic Depth

64. Binocular Eye convergence Stereoscopic Depth Problems with Stereoscopic Displays Making Effective Stereoscopic Displays

65. Vergence Angle

66. Simple Stereo Display

67. Frame Cancellation

68. Geometry of Virtual Eye Separation

69. Artificial Spatial Cues Dropping Lines to Ground Plane

70. Artificial Spatial Cues Proximity Luminance Covariance or Depth Cueing

71. Depth Cues in Combination Vergence Kinetic depth Depth of focus Shadows Shading Occlusion Linear perspective Texture gradients Stereo

72. Task-Based Space Perception Tracing Data Paths in 3D Graphs Judging the Morphology of Surfaces and Target Detection Patterns of Points in 3D Space Judging Relative Positions of Objects in Space Judging the Relative Movement of Self within the Environment Judging the “Up” Direction The Esthetic Impression of 3D Space (Presence)

73. Is there more space in 3D? 1D has how much data display space? 2D has how much data display space? 3D? Stereo 1.6 Motion 2.2 Stereo and motion 3.0

74. http://www.illusionworks.com/ http://www.psychology.psych.ndsu.nodak.edu/mccourt/website/htdocs/HomePage/ Projects/Brightness/Brightness%20Perception.htm http://psy.ucsd.edu/~sanstis/SASlides.html