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Course Information: 91.546 Computer Graphics I

Instructor: Dr. Hugh MastermanThe MITRE Corporationemail: hcm@mitre.org

Texts: Interactive Computer Graphics (5th edition)Angel, EdwardAddison Wesley 2006

ISBN 0-321-53586-3

OpenGL Programming Guide (6th edition)Neider, Davis, &WooAddison Wesley 2008ISBN 0-321-48100-3

Website: http://www.cs.uml.edu/~hmasterm/graphics1.html

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Computer Graphics

Computer graphics is the discipline concerned with all aspects of producing pictures or images using a computer.

Interactive computer graphics implies user is in the loop offeedback process:

ChangeImage

Reactto

Change

Graphics System User

InputDevice

Display

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axiom A

rule A = [&FL!A]>>>>>'[&FL!A]>>>>>>>'[&FL!A]rule F = S>>>>>F

rule S = F Lrule L = ['''^^c(4){-f+f+f-|-f+f+f}c(12)]

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SAGE Air Defense System: ca. 1958

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Ivan Sutherland Sketchpad (1963)

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Computer Aided Design 1965 - Present

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Screen Shot:Xerox Star ca. 1974

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Early Night Simulator ca. 1970

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Raster Graphics Daylight Simulator 1985

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MD90 Cockpit Simulator 1990

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Military Simulation: Realistic Environment

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Data Visualization

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Weather Visualization

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Virtual Reality

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Computer Animation

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Computer Art

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Computer Art

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Graphics: Conceptual Model

Real Object

Real Object

Human Eye

Human Eye

DisplayDevice

Graphics System

SyntheticModel

SyntheticCamera

Real Light

SyntheticLight Source

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Computer GraphicsConceptual Model

ApplicationModel

ApplicationProgram Graphics

System

OutputDevices

InputDevices

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What is an Image?

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Nature of Light

350 780 (nm)

RadioIRX-rays Light

Electromagnetic (wave) radiation:

Particle:

Ray propagationQuantum energy E=h

Amplitude: LFrequency: Velocity: c

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Characterization of Light

Direction, Amplitude, Wavelength:

( d, L,)

Is this enough? Real world light rarely consistsof a single wavelength!

L

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Human Eye

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Human Perception of Color – 3 Types of Cones

L()

d

d

d

)()SL(=ityRed_Intens

)()SL(=nsityGreen_Inte

)()SL(=sityBlue_Inten

b

a

b

a

b

a

r

g

b

L() (R,G,B)

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Metameric Colors

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RGB Color Space

Green(0,1,0)

Blue(0,0,1)

Red(1,0,0)

Yellow(1,1,0)

Magenta(1,0,1)

Blk

Cyan(0,1,1)

White(1,1,1)

G

B

R

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CIE Color Space

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HSL Color Space

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Combination of Primary Colors

Additive Color Subtractive Color

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Output Devices

0 Hard copy

- Printers

=Dot matrix

=Ink jet

=Thermal transfer

=Laser

- Plotters

0 Soft copy

- CRT

- Flat panel

=LCD

=Electroluminescent

=Plasma

- Projector

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Flat Panel Pixel Arrangements

R G B R G B R

G B R G B R

R G B R G B R

R G

G B

R G

G B

R G

G B

R G

G B

Triad Stripe Quad

R G B

R G B

R G B

R G B

R G B

R G B

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CRT: Raster Scan

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Color CRT Phosphor PatternVersus Spot Size

R

R BG R

BG R BG

B R BG R G

BG R BG

R BG R

Spot Size

Dot Pitch

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RGB Components ofan Image

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Raster Display System ArchitectureWith Peripheral Display Processor

System Bus

CPU

DPMemory

FrameBuffer

I/O

VideoController

DisplayDisplay

Processor

SystemMemory

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Monochrome Frame Buffer

1 0 1 1 0 0 1 1

D/AConverter

Bit 1

Bit 2

Bit 3

Bit 4

Bit n CRT

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Color Frame Buffer

1 0 1 1 0 0 1 1

Bit 1

Bit 2

Bit 3

Bit 4

Bit n

CRT

0 1 0 1

RedD/A

GreenD/A

BlueD/A

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Video Look-up Table

1 0 1 1 0 0 1 1

CRT

0 1 0 1

RedD/A

GreenD/A

BlueD/A

1 0 1 1 0 0 1 1 0 1 0 1

Look Up Table

Bit 1Bit 2

Bit 3Bit 4

Bit n

1 0 1 1 0 0 1 1

179

178

180

= 179

177