Page 1

The Visual Computer

Pat Hanrahan

Computer Science DepartmentStanford University

Mantras

Observation

Abstraction and Illustration

Interaction

Visual Thinking

Page 2

History of Scientific Images

Images of Science

B. J. Ford, 1992

The Art of the Engineer

Baynes and Pugh, 1981

Picturing Knowledge

Ed. B. S. Baigre, 1996

Purposes of Scientific Images

Records of observations

Self-illustrating phenomena

Concepts and classifications

Descriptions of equipment and methodology

vs.

Exploration

Presentation

The Scientific Image

H. Robin, 1992

Page 3

Robert Hooke, F.R.S

Flea

Curator of Experiments

Illustrations

Santiago Ramon Y Cajal (1894) Cell Types in the CerrebellumFrom Robin, p. 44

Page 4

rarefaction initial interface location

shockinterface

Tariq Aslam, LANL

From Physics to Phenomena

Self-Illustrating Phenomena

Page 5

Self-Illustrating Phenomena

Harrier Jet flow during landingNASA Ames FAST System

Eric Schulzinger (1988)Air-Flow on a Supersonic AircraftFrom Robin, p. 141

Realism in Art

Piero della Francesca, The Flagellation of Christc. 1465

Johannes VermeerThe Music Lessonc. 1670

PerspectiveLight and Color

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Engineering Drawings

Drawing of the engine for John Wilkinson, 1796From Baynes and Pugh, 1981, p. 69

Isometric Perspective

William Farrish

Page 7

Linear Progress?

Simplistic CG view of the world of image-making- Started with cave paintings- To renaissance art

Invention of perspective and shading- To computer graphics

Physical simulation of lights, cameras, materials

- Will culminate in VR/total immersionComplete control of sensorimotor field

The bushy tree of abstraction is still largely unexplored in CG

Route MapsConventional Route Overlay Route Map Sketch

Agrawala and Stolte, Rendering Effective Route Maps, to appear SIGGRAPH 2001

Approach1. Find cognitive and perceptual principles that produce effective

visualizations2. Encode these principles into a optimization functional3. Optimize the layout

Page 8

Stolte and Hanrahan, Polaris, InfoVis 2000

Depiction

How to map information to graphics

Central problem in visualization

Formal systems needed; composition

Need high-level tools to make this easy

Understand the geometric properties

Cognitive/perceptual adv/disadv

Too much emphasis on new metaphors!

Key theorists: Bertin, Cleveland, Mackinlay, MacEachren, Wilkinson

Page 9

The Power of Interaction

Gibson’s Experiment

Goal: Match 2 shapes

Active touch: 96%

Passive (rotation) 72%

Passive (imprint) 49%

From J. J. Gibson (1966)The Senses Considered as a PerceptualSystem, p. 124

Thanks to David Kirsh for this example.

Graphical Representations

Visual Proof:

1+3+5+7+9=52

Pythagorean Theorem

Chinese Proof by Dissection

Page 10

Cartographic Projection

Equiheading vs. Equidistance Projection

Mental Imagery

R. Shepard’s

Mental Rotation

B. Morin’s (who is blind)

Sphere Eversion

From G. Francis, The

Topological Picturebook

Page 11

Themes

Perception and observation vs. just reasoning

Illustrations vs. just reproductions

Interaction vs. just batch

Visual and spatial thinking vs. just symbol manipulation

More Specifically

Appreciate the culture of scientific imagery

Learn to observe, to draw (art and science)

Handling complexity via abstraction

Simple techniques (plots, eng. drawings) are the most sophisticated

Beyond simulating media towards creating illustrations

Depictions: formalisms and tools

Image and Meaning Conference, MIT,

June 2001