This document discusses feature level processing and lessons for information display from pre-attentive vision research. It covers topics like segmentation based on primitive visual features like color, orientation, and motion. Key points made are that some features like color can be processed in parallel across the visual field and "pop out", while conjunctions of features require focused attention. The document also provides guidance on designing visual symbols and data glyphs, recommending using separable perceptual dimensions and following principles of pre-attentive processing to ensure important information is available to attention.

1. Feature Level Processing
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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).
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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. stereo
form
color
form
stereo
form
color
form
stereo
MT movement/stereo
Livingston and
Hubel
Neural Architecture
form
form
color
color
movement movement
1
2&3
4A Visual Area 2
4B
4C
5
6
Visual Area 1 (Primary Visual Cortex)

8. Orientation and Size
(Gabor primitives)

9. Image segmentation based on
texture
Vertical fat Gabor
filters respond most
strongly
Horizontal skinny
Gabor filters respond
most strongly
Resulting
Segmentation

10. Vector fields like using gabors

11. Pre-Attentive Processing
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12. Color is Pre-Attentive (Pops out)
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9 0 9 4 9 70 9
7 5 2 0 6 6 84
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0 8 0 30 9 - 8
8 0 8 0 8 58 0
0 8 0 8 0 0 28
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13. Generic Pre-Attentive Experiment
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900
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700
500
3
6
12
Number of distractors
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
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Must stand out on some simple dimension
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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
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
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Allows for various topological range
highlighting methods
MEGraph
Goal
from 30 to 2000 nodes

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

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

49. Starplot glyph

50. Spotfire product

55. Integral and Separable dimension
(Garner)
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Can we read display attributes
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Independently
Holistically
Speeded classification task. Sort into two
piles on one dimension or another

56. Integral
red-green
yellow-blue
black-white
red-green
x-size
y-size
Color
orientation
Motion
Color
Separable

57. Lessons for Information Display
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Orthogonality - use a
different channel for a
different type of
information
If you need this use
separable challenge
If you need to highlight
by two properties use
separable dimensions.

59. The programmable filter
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We can only look for patterns of simple features
Conjunctions of shape, color cannot be
programmed for parallel search of field
Conjunctions of depth/motion and color/shape
can be
Integral dimensions tend to be seen holistically
cannot be separated
Separable dimensions tend to be seen
separately

60. Searchlight Model of Attention
U fu V al
se l isu
F ldo V
ie f iew
V a
isu l
Sa o
e rch r
M n rin
o ito g
S te y
tra g
Ee
y
Mv m t
o e en
Cn l
o tro

61. Searchlight Properties
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Size varies with data density
Size varies with stress level
Attention operators work within the
searchlight beam
Attention is a tunable filter
Eye movements 3/sec – A series of
saccades