Feature Level Processing

1. Feature Level Processing • Lessons from low-level vision • Applications in Highlighting • Icon (symbol) design • Glyph design

2. Spotfire product

3. Visual symbols

4. Architecture for visual thinking

5. Primitives of Perception (the phonemes). • The whole visual field is processed in parallel • This machinery tells us what kinds of information are easily distinguished • Popout effects (general attention) • Segmentation effects (dividing up the visual field)

6. Segmentation by Primitive Features

7. Livingston and HubelNeural Architecture

8. Orientation and Size(Gabor primitives)

9. Image segmentation based on texture

10. Vector fields like using gabors

11. Pre-Attentive Processing

12. Color is Pre-Attentive (Pops out)

13. Generic Pre-Attentive Experiment • Number of irrelevant items varies • Pre-attentive 10 msec per item or better.

14. Color

16. Orientation

18. Motion

20. Size

22. Simple shading

24. Conjunction (does not pop out)

25. Semantic Depth of Field

27. Compound features (do not pop out)

29. Surrounded colors do not pop out

31. Laws of pre attentive display • Must stand out on some simple dimension • color, • simple shape = orientation, size • motion, • depth • Lessons for highlighting – one of each

32. Lessons: Highlighting how to make information available to attention Using color Using underlining A flying box leads attention Blinking momentarily attracts attention Blinking momentarily attracts attention Motion elicits an orienting response

33. More Pre-Attentive

34. Conjunction (does not pop out)

35. Pre-attentive conjunction

36. Conjunctions of motion and shape do pop out. (color also?) • McLeod, P., Driver, J. and Crisp, J. (1988) Visual search for a conjunction of movement and form is parallel. Nature 332, 154-155. • Driver, J., MacLeod, P. and Dienes, Z. (1992) Motion coherence and conjunction search: Implications for guided search theory. Perception and Psychophysics. 51, 1, 79-85.

37. MEGraph: Experimental system • Allows for various topological range highlighting methods MEGraph Goal from 30 to 2000 nodes

38. Pre-Attentive Channels • Form (orientation/size) • Color • Simple motion/blinking • Addition/numerosity (up to 3) • Spatial, stereo depth, shading, position

39. Pre-Attentive Conjunctions • Stereo and color • Color and motion • Color and position • Shape and position • In general: spatial location and some aspect of form

40. Pre-Attentive Lessons • Rapid visual search (10 msec/item) • Easy to attend to • Makes symbols distinct • Based on simple visual attributes • Faces, etc are not pre-attentive

41. Designing symbols

42. Perceptual Channels • Color (3) • Shape (size, orient) • Motion (2?) • Texture (2++) • Position (x,y)

43. Spatial Channels Like interferes with like

44. Size contrast effect

45. Orient contrast

46. Size contrast effects can cause errors in information display

47. Chris Weigle: orientation channels for info display

48. Position (2) Orientation (1) Size (spatial frequency) Motion (2)++ Blinking? Color (3) Note we have the problem of heterogeneity – There is no good solution Mapping data to display variablesData glyphs Star glyph Method

49. Starplot glyph

50. Spotfire product