Speaker: Emily Chen, Janet Huang, Evelyn Hung

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Perception in Visualization
Christopher G. Healey Department of Computer
Science, North Carolina State University

• Speaker Emily Chen, Janet Huang, Evelyn Hung
• From CSIE

Reference Perception in Visualization
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What visual properties draw our eyes?
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Preattentive Processing

• Features

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Color
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Shape
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Color and Shape
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Feature Hierarchy
color
color with shape noisy
shape
shape with color noisy
Color is a more obvious feature!!
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Feature Hierarchy (application)
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Motion
velocity of motion
direction of motion
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Motion (application)
Reference http//www.geom.uiuc.edu/docs/research/
webviz/webviz/node2.html
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Preattentive Processing

• Theories
• Feature Integration Theory
• Similarity Theory
• Guide Search Theory

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Feature Integration Theory
orientation
blue
contrast
yellow
size
green
luminance
red
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Reference http//marumushi.com/apps/newsmap/newsm
ap.cfm
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Similarity Theory
N-N similarity high -gt easy search
N-N similarity low -gt difficult search
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Similarity Theory
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Guide Search Theory
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What we see in a dynamic scene?
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Change Blindness

• The phenomenon
• A person fails to detect large changes in a scene
• Only a little features are recognized
• Details cannot be remembered
• Except in viewers attention area

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More Examples (1/3)
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Explanations for Change Blindness

• Overwriting

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More Examples (2/3)
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Explanations for Change Blindness

• Overwriting
• Nothing is stored

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More Examples (3/3)
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Explanations for Change Blindness

• Overwriting
• Nothing is stored
• First impression
• Everything is stored, nothing is compared
• Feature combination

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Explanations for Change Blindness
Reference Simons, D. J. Current approaches to
change blindness. Visual Cognition 7, 1/2/3
(2000), 115.
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The Usage of Change Blindness

• What we see depends on
• Our goals and expectations
• The light entering our eyes
• We want to produce salient images
• Strive the eye to the important areas

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Avoid Change Blindness
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Summary

• Design good UI using preattentive features and
  theories
• Consider change blindness
• Use it or avoid it!

• Question
• Are there any other preattentive features?
• How to use the phenomena of change blindness?

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Visual Illusion
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