Visual Perception & Graphical Principles

Seminar on Information Visualization

Daniele Della Bruna

winter 2006 @ university of Fribourg

IntroductionPreattentive perception

Introduction

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- Perception in visualization

- Power of visualization

- Color use guidelines

IntroductionPreattentive perception

Preattentive perception

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- Eye movements take at least 200 msec to initiate

-Tasks performed in less than 200-250 msec are considered preattentive

-A limited set of visual properties are detected veryrapidly by the low-level visual system

IntroductionPreattentive perception

Preattentive perception

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

IntroductionPreattentive perception

Demo preattentive

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- Demo

IntroductionPreattentive perception

Theories

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

-Feature integration theory: a set of feature maps ;each feature map registers in parallel activity in response to a specific feature

-Texton Theory: a group of features ; only difference intextons or in their density can be detected

-Similarity Theory: search time is based on T-N and N-N values

-Guided Search Theory: features maps filtered into multiplecategories (colourred/green/blue/yellow)

IntroductionPreattentive perception

Postattentive vision

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

-attention allow a viewer to learn what is it in a scene,but it does not allow the viewer to see the scene in a different manner

-preattentive visual representation appears to be identicalafter the viewer studied it

-What we see when confronted with a new scene dependsas much on our expectations

-an interruption in what is being seen renders us “blind” tosignificant changes

IntroductionPreattentive perception

Demo postattentive

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

IntroductionPreattentive perception

Demo postattentive

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

IntroductionPreattentive perception

Demo postattentive

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

IntroductionPreattentive perception

Not lie with visualization

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- How data are represented visually has a powerfuleffect on how is perceived

- It can significantly influence the user’s interpretationof the data

IntroductionPreattentive perception

Demo visualization

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

IntroductionPreattentive perception

Colour use guidelines

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- Colours can help the understanding of a graph

- 4 different colour schemes

-Qualitative-Binary-Diverging-Sequential

IntroductionPreattentive perception

Qualitative / Binary

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

-Qualitative: data of different categories are usually represented in an effective way by means of differences in hue

- Binary: A binary scheme is a qualitative scheme where there are only two categories

IntroductionPreattentive perception

Diverging / Sequential

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- Diverging: In a diverging scheme data can be grouped in two sets that show two different trends around a balance or theshold point

-Sequential: To represent ordered data in sequential form the common recommendation is using variations in lightness or saturation of a given hue

IntroductionPreattentive perception

Combinations

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- Finally these four possibilities can be combined among them to obtain up to 10 commendable bivariate schemes

IntroductionPreattentive perception

Problems in colour appearance

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Colour use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in colour appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

- colorblind

IntroductionPreattentive perception

Questions

Demo preattentiveTheoriesPostattentive visionDemo postattentive

Demo visualization

Demo postattentiveDemo postattentive Not lie with visualization

Color use guidelinesQualitative / BinaryDiverging / SequentialCombinationsProblems in color appearanceQuestions

Daniele Della Bruna – Visual Perception & Graphical Principles ; Seminar winter 2006

?