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Course Information: 91.546 Computer Graphics I Instructor: Dr. Hugh Masterman The MITRE Corporation 781-271-3248 email: hcm@mitre.org Texts: Interactive Computer Graphics (4 th edition) Angel, Edward Addison Wesley 2001 ISBN 0-321-32137-5
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Course Information: 91.546 Computer Graphics I Instructor: Dr. Hugh Masterman The MITRE Corporation 781-271-3248 email: hcm@mitre.org Texts: Interactive Computer Graphics (4th edition) Angel, Edward Addison Wesley 2001 ISBN 0-321-32137-5 OpenGL Programming Guide (4th edition) Neider, Davis, &Woo Addison Wesley 1999 ISBN 0-321-17348-1 Website: http://www.cs.uml.edu/~hmasterm/graphics1.html
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 of feedback process: Graphics System User Display React to Change Change Image Input Device
History of Computer Graphics • Whirlwind computer at MIT: SAGE (1950s) • Sketchpad (Ivan Sutherland, MIT 1963) • Computer Aided Design (CAD) 1965 - • Simulators (c.1975-) • Bitmap graphical user interfaces (late 70s) • Virtual reality (late 80s - ) • Computer animation • Visualization • Computer art • Web/Internet based graphics For a more detailed historical timeline
Graphics: Conceptual Model Real Light Human Eye Real Object Synthetic Light Source Synthetic Camera Human Eye Synthetic Model Real Object Display Device Graphics System
Computer GraphicsConceptual Model Output Devices Application Program Application Model Graphics System Input Devices
X-rays Light IR Radio 350 l (nm) 780 Nature of Light Electromagnetic (wave) radiation: l Amplitude: L Frequency: n Velocity: c Particle: Ray propagation Quantum energy E=hn
Direction, Amplitude, Wavelength: ( d, L, l) L l Characterization of Light Is this enough? Real world light rarely consists of a single wavelength!
Human Perception of Color Sb Sg Sr l l l L(l) l
RGB Color Space G Green (0,1,0) Yellow (1,1,0) White (1,1,1) Cyan (0,1,1) Red (1,0,0) R Blk Blue (0,0,1) Magenta (1,0,1) B
Additive Color Red Magenta Yellow White Cyan Blue Green
Hard copy Printers Dot matrix Ink jet Thermal transfer Laser Plotters Soft copy CRT Flat panel LCD Electroluminescent Plasma Projector Output Devices
530 520 0.8 540 510 Green 0.7 lc nm 550 AMLCD (Metal Halide) 560 0.6 Green 570 500 0.5 Green 580 CRT 590 y 0.4 600 610 Red 620 Red 490 0.3 640 Blue 770 0.2 AMLCD (Halogen) 480 0.1 Blue 470 Blue 460 450 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Color Gamut: 1996
Cathode Ray Tubes AdvantagesLimitations Very LOW cost Large volume/weight Good visual quality Size < 45 inches Wide viewing angle Repeatability Simple grayscale High voltage Simple addressing Large manufacturing base
Unpolarized Unpolarized Light Source Light Source Rear Linear Polarizer Polarized Light REAR GLASS REAR GLASS Polymeric 90 Degree Alignment Layer "Twist" FRONT GLASS FRONT GLASS Liquid-Crystal Molecules Transparent Transmitted No Light Electrodes Light Transmission ( ~ < 10% Source) Front Linear Polarizer Liquid Crystal Display (LCD)
Liquid Crystal Displays • AdvantagesLimitations • Thin/low weight Image size < 13 inches (passive)Rugged and reliable < 16 inches (active matrix) • Low voltage drivers Response time (passive) • Premium cost (active matrix) • Limited viewing angle • Limited temperature range
CRT Projection System Liquid Cooled CRT Multielement Lens Assembly CRT: 5 to 13 Inches Lens: F1.0 to F1.2 Screen Red Video Drive Electronics Video Green Blue Deflection Electronics Digital Convergence Static/Dynamic Focus Video Control Microprocessor System Automatic Convergence – Multisync Autolock Control – Convergence and Setup Files – Automatic Convergence Control – Diagnostics – On-Line Setup Instructions – Remote Control IR Line Remote Control RS232/422 Remote Status/Control
Reflection Mirror G Dichroic Projection Reflector Lens Metal-Halide R Lamp B Reflection Mirror Liquid-Crystal Condenser UV, IR Filter Panel Lens LCD Projector Dichroic Mirrors
Head-Mounted Displays (1999) CyberEye 200 180K Pixels/LCD 27.5 deg. FOV Weight 14 oz. ~$2,500 Kaiser ProView 30 300K Pixels/LCD 30 deg. FOV Weight 32 oz. ~$8,000 N-Vision Datavisor 80 1,300K Pixels/CRT 80 deg. FOV Weight 64 oz. ~$100,000
CAVE CAVE available commercially from Pyramid Systems, Inc.
Display Common Raster DisplaySystem Architecture Frame Buffer Video Controller Memory CPU System Bus I/O
Display Common Single Address SpaceRaster Display System Architecture Frame Buffer Video Controller Memory CPU System Bus Display Processor I/O
I/O Display Processor DP Memory Frame Buffer Raster Display System ArchitectureWith Peripheral Display Processor System Memory CPU System Bus Video Controller Display
D/A Converter Monochrome Frame Buffer Bit n CRT 1 0 1 1 0 0 1 1 Bit 4 Bit 3 Bit 2 Bit 1
Color Frame Buffer CRT Red D/A Green D/A Blue D/A Bit n 1 0 1 1 0 0 1 1 0 1 0 1 Bit 4 Bit 3 Bit 2 Bit 1
1 0 1 1 0 0 1 1 Bit n Bit 4 Bit 3 Bit 2 Bit 1 Video Look-up Table = 179 CRT Look Up Table Red D/A Green D/A Blue D/A 177 178 1 0 1 1 0 0 1 1 0 1 0 1 179 1 0 1 1 0 0 1 1 0 1 0 1 180