ubi 516 advanced computer graphics aydın Öztürk [email protected] ozturk aydın Öztürk...

UBI 516 Advanced Computer Graphics

Aydın ÖztürkAydın Öztürk

ozturkozturk@@ube.ege.edu.trube.ege.edu.trhttp://www.http://www.ube.ege.edu.tr/~ozturkube.ege.edu.tr/~ozturk

Aydın ÖztürkAydın Öztürk

ozturkozturk@@ube.ege.edu.trube.ege.edu.trhttp://www.http://www.ube.ege.edu.tr/~ozturkube.ege.edu.tr/~ozturk

Administrivia

SyllabusSyllabus

• Instructor/TA coordinatesInstructor/TA coordinates

• PrereqsPrereqs

• TextsTexts

• Assignments Assignments

• Topic listTopic list

SyllabusSyllabus

• Instructor/TA coordinatesInstructor/TA coordinates

• PrereqsPrereqs

• TextsTexts

• Assignments Assignments

• Topic listTopic list

Textbook

• Computer Graphics with OpenGLComputer Graphics with OpenGL

– Third EditionThird Edition

– Hearn and BakerHearn and Baker

• Computer Graphics with OpenGLComputer Graphics with OpenGL

– Third EditionThird Edition

– Hearn and BakerHearn and Baker

The Basics

Computer graphics: generating 2D images of Computer graphics: generating 2D images of a 3D world represented in a computer.a 3D world represented in a computer.

Main tasks:Main tasks:

• modelingmodeling: creating and representing the geometry of : creating and representing the geometry of objects in the 3D worldobjects in the 3D world

• renderingrendering: generating 2D images of the objects: generating 2D images of the objects

• animationanimation: describing how objects change in time: describing how objects change in time

Computer graphics: generating 2D images of Computer graphics: generating 2D images of a 3D world represented in a computer.a 3D world represented in a computer.

Main tasks:Main tasks:

• modelingmodeling: creating and representing the geometry of : creating and representing the geometry of objects in the 3D worldobjects in the 3D world

• renderingrendering: generating 2D images of the objects: generating 2D images of the objects

• animationanimation: describing how objects change in time: describing how objects change in time

Why Study Computer Graphics?

Graphics is coolGraphics is cool

• I like to see what I’m doingI like to see what I’m doing

• I like to show people what I’m doingI like to show people what I’m doing

Graphics is interestingGraphics is interesting

• Involves Involves simulationsimulation, , algorithmsalgorithms, , architecturearchitecture……

I’ll never get an Oscar for my actingI’ll never get an Oscar for my acting

• But maybe I’ll get one for my CG special effectsBut maybe I’ll get one for my CG special effects

Graphics is funGraphics is fun

Graphics is coolGraphics is cool

• I like to see what I’m doingI like to see what I’m doing

• I like to show people what I’m doingI like to show people what I’m doing

Graphics is interestingGraphics is interesting

• Involves Involves simulationsimulation, , algorithmsalgorithms, , architecturearchitecture……

I’ll never get an Oscar for my actingI’ll never get an Oscar for my acting

• But maybe I’ll get one for my CG special effectsBut maybe I’ll get one for my CG special effects

Graphics is funGraphics is fun

Graphics Applications

Entertainment: CinemaEntertainment: CinemaEntertainment: CinemaEntertainment: Cinema

Pixar: Monster’s Inc. Square: Final Fantasy

Final Fantasy (Square, USA)


Entertainment: CinemaEntertainment: CinemaEntertainment: CinemaEntertainment: Cinema


GT Racer 3

Polyphony Digital: Gran Turismo 3, A Spec

Entertainment: GamesEntertainment: GamesEntertainment: GamesEntertainment: Games


Video GamesVideo GamesVideo GamesVideo Games


Medical VisualizationMedical VisualizationMedical VisualizationMedical Visualization

MIT: Image-Guided Surgery Project

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Computer Aided Design (CAD)Computer Aided Design (CAD)Computer Aided Design (CAD)Computer Aided Design (CAD)


Scientific VisualizationScientific VisualizationScientific VisualizationScientific Visualization


Everyday UseEveryday Use

• Microsoft’s Whistler OS will use graphics seriouslyMicrosoft’s Whistler OS will use graphics seriously

• Graphics visualizations and debuggersGraphics visualizations and debuggers

• Visualize complex software systemsVisualize complex software systems

Everyday UseEveryday Use

• Microsoft’s Whistler OS will use graphics seriouslyMicrosoft’s Whistler OS will use graphics seriously

• Graphics visualizations and debuggersGraphics visualizations and debuggers

• Visualize complex software systemsVisualize complex software systems

Everyday use

Everyday use

Window system and large-screen interaction metaphors (François Guimbretière)

Education

Outside In (Geometry Center, University of Minnesota)

Current Technologies

Impact of Computers

Moore’s LawMoore’s Law

Power of a CPU doubles every 18 months / 2 yearsPower of a CPU doubles every 18 months / 2 years

Moore’s LawMoore’s Law

Power of a CPU doubles every 18 months / 2 yearsPower of a CPU doubles every 18 months / 2 years

Impact of Video Games (Nvidia)

Number of transistors on GPU doubles each 6 moNumber of transistors on GPU doubles each 6 monthnths.s.

• Three times Moore’s LawThree times Moore’s Law

– Good article on Jen-Hsun Huang, Nvidia CEO: Good article on Jen-Hsun Huang, Nvidia CEO: http://www.wired.com/wired/archive/10.07/Nvidia_pr.htmlhttp://www.wired.com/wired/archive/10.07/Nvidia_pr.html

Number of transistors on GPU doubles each 6 moNumber of transistors on GPU doubles each 6 monthnths.s.

• Three times Moore’s LawThree times Moore’s Law

– Good article on Jen-Hsun Huang, Nvidia CEO: Good article on Jen-Hsun Huang, Nvidia CEO: http://www.wired.com/wired/archive/10.07/Nvidia_pr.htmlhttp://www.wired.com/wired/archive/10.07/Nvidia_pr.html

$7 Billion Man $5.6 Billion Man

Worldwiderevenues

Retro flashback???Lee Majors

Col. Steve Austin

Impact of Video Games

But…But…

• Video game sales is roughly same as Hollywood box Video game sales is roughly same as Hollywood box officeoffice

• Americans bought $3.2 billion in VCRs and DVDs in Americans bought $3.2 billion in VCRs and DVDs in 20022002

• Total revenues to movie studios is 5 times total video Total revenues to movie studios is 5 times total video game revenuesgame revenues

But…But…

• Video game sales is roughly same as Hollywood box Video game sales is roughly same as Hollywood box officeoffice

• Americans bought $3.2 billion in VCRs and DVDs in Americans bought $3.2 billion in VCRs and DVDs in 20022002

• Total revenues to movie studios is 5 times total video Total revenues to movie studios is 5 times total video game revenuesgame revenues

Future of Consoles

• 33 million PS2s (in 2002)33 million PS2s (in 2002)

• 3.9 million Xboxes (in 2002)3.9 million Xboxes (in 2002)

– MSFT still losing lots of $$ per consoleMSFT still losing lots of $$ per console

• Predicted 200 million PDA/Cell game players in 2005Predicted 200 million PDA/Cell game players in 2005

• 33 million PS2s (in 2002)33 million PS2s (in 2002)

• 3.9 million Xboxes (in 2002)3.9 million Xboxes (in 2002)

– MSFT still losing lots of $$ per consoleMSFT still losing lots of $$ per console

• Predicted 200 million PDA/Cell game players in 2005Predicted 200 million PDA/Cell game players in 2005

Display technologies

Cathode Ray Tubes (CRTs)Cathode Ray Tubes (CRTs)

• Most common display device todayMost common display device today

• Evacuated glass bottleEvacuated glass bottle

• Extremely high voltageExtremely high voltage

Cathode Ray Tubes (CRTs)Cathode Ray Tubes (CRTs)

• Most common display device todayMost common display device today

• Evacuated glass bottleEvacuated glass bottle

• Extremely high voltageExtremely high voltage

CRT details• Heating element Heating element

(filament)(filament)

• Electrons pulled Electrons pulled towards towards anode focusing anode focusing cylindercylinder

• Vertical and Vertical and horizontal horizontal deflection platesdeflection plates

• Beam strikes Beam strikes phosphor coating phosphor coating on front of tubeon front of tube

• Heating element Heating element (filament)(filament)

• Electrons pulled Electrons pulled towards towards anode focusing anode focusing cylindercylinder

• Vertical and Vertical and horizontal horizontal deflection platesdeflection plates

• Beam strikes Beam strikes phosphor coating phosphor coating on front of tubeon front of tube

Electron Gun

Contains a filament that, when heated, emits a stream of Contains a filament that, when heated, emits a stream of electronselectrons

Electrons are focused with an electromagnet into a sharp Electrons are focused with an electromagnet into a sharp beam and directed to a specific point of the face of the beam and directed to a specific point of the face of the picture tubepicture tube

The front surface of the picture tube is coated with small The front surface of the picture tube is coated with small phospher dotsphospher dots

When the beam hits a phospher dot it glows with a When the beam hits a phospher dot it glows with a brightness proportional to the strength of the beam and brightness proportional to the strength of the beam and how long it is hithow long it is hit

Contains a filament that, when heated, emits a stream of Contains a filament that, when heated, emits a stream of electronselectrons

Electrons are focused with an electromagnet into a sharp Electrons are focused with an electromagnet into a sharp beam and directed to a specific point of the face of the beam and directed to a specific point of the face of the picture tubepicture tube

The front surface of the picture tube is coated with small The front surface of the picture tube is coated with small phospher dotsphospher dots

When the beam hits a phospher dot it glows with a When the beam hits a phospher dot it glows with a brightness proportional to the strength of the beam and brightness proportional to the strength of the beam and how long it is hithow long it is hit

CRT characteristicsWhat’s the largest (diagonal) CRT you’ve seen?What’s the largest (diagonal) CRT you’ve seen?

• Why is that the largest?Why is that the largest?

– Evacuated tube == massive glassEvacuated tube == massive glass

– Symmetrical electron paths (corners vs. center)Symmetrical electron paths (corners vs. center)

How might one measure CRT capabilities?How might one measure CRT capabilities?

• Size of tubeSize of tube

• Brightness of phosphers vs. darkness of tubeBrightness of phosphers vs. darkness of tube

• Speed of electron gunSpeed of electron gun

• Width of electron beam Width of electron beam

• Pixels?Pixels?

What’s the largest (diagonal) CRT you’ve seen?What’s the largest (diagonal) CRT you’ve seen?

• Why is that the largest?Why is that the largest?

– Evacuated tube == massive glassEvacuated tube == massive glass

– Symmetrical electron paths (corners vs. center)Symmetrical electron paths (corners vs. center)

How might one measure CRT capabilities?How might one measure CRT capabilities?

• Size of tubeSize of tube

• Brightness of phosphers vs. darkness of tubeBrightness of phosphers vs. darkness of tube

• Speed of electron gunSpeed of electron gun

• Width of electron beam Width of electron beam

• Pixels?Pixels?

Display technologies: CRTs

Vector DisplaysVector Displays

• Anybody remember Anybody remember BattlezoneBattlezone? ? TempestTempest? ?

Display Technologies: CRTs


• Early computer displays: basically an oscilloscopeEarly computer displays: basically an oscilloscope

• Control X,Y with vertical/horizontal plate voltage Control X,Y with vertical/horizontal plate voltage

• Often used intensity as ZOften used intensity as Z

Name two disadvantagesName two disadvantages

Just does wireframeJust does wireframe

Complex scenes Complex scenes causecause visible flicker visible flicker


• Early computer displays: basically an oscilloscopeEarly computer displays: basically an oscilloscope

• Control X,Y with vertical/horizontal plate voltage Control X,Y with vertical/horizontal plate voltage

• Often used intensity as ZOften used intensity as Z

Name two disadvantagesName two disadvantages

Just does wireframeJust does wireframe

Complex scenes Complex scenes causecause visible flicker visible flicker


Raster DisplaysRaster Displays

• Raster: A rectangular array of points or dotsRaster: A rectangular array of points or dots

• Pixel: One dot or picture element of the rasterPixel: One dot or picture element of the raster

• Scan line: A row of pixelsScan line: A row of pixels


• Raster: A rectangular array of points or dotsRaster: A rectangular array of points or dots

• Pixel: One dot or picture element of the rasterPixel: One dot or picture element of the raster

• Scan line: A row of pixelsScan line: A row of pixels

Display technologies: CRTs


• Black and white television: an oscilloscope with a fixed Black and white television: an oscilloscope with a fixed scan pattern: left to right, top to bottomscan pattern: left to right, top to bottom

– As beam sweeps across entire face of CRT, beam As beam sweeps across entire face of CRT, beam intensity changes to reflect brightnessintensity changes to reflect brightness

• Analog signal vs. digital displayAnalog signal vs. digital display


• Black and white television: an oscilloscope with a fixed Black and white television: an oscilloscope with a fixed scan pattern: left to right, top to bottomscan pattern: left to right, top to bottom

– As beam sweeps across entire face of CRT, beam As beam sweeps across entire face of CRT, beam intensity changes to reflect brightnessintensity changes to reflect brightness

• Analog signal vs. digital displayAnalog signal vs. digital display

Display technologies: CRT

Can a computer display work like a black and white Can a computer display work like a black and white TV?TV?

• Must synchronizeMust synchronize

– Your program makes decisions about the intensity signal at Your program makes decisions about the intensity signal at the pace of the CPU…the pace of the CPU…

– The screen is “painted” at the pace of the electron gun The screen is “painted” at the pace of the electron gun scanning the rasterscanning the raster

• Solution: special memory to buffer image with scan-out Solution: special memory to buffer image with scan-out synchronous to the raster. We call this the synchronous to the raster. We call this the framebufferframebuffer..

• Digital description to analog signal to digital displayDigital description to analog signal to digital display

Can a computer display work like a black and white Can a computer display work like a black and white TV?TV?

• Must synchronizeMust synchronize

– Your program makes decisions about the intensity signal at Your program makes decisions about the intensity signal at the pace of the CPU…the pace of the CPU…

– The screen is “painted” at the pace of the electron gun The screen is “painted” at the pace of the electron gun scanning the rasterscanning the raster

• Solution: special memory to buffer image with scan-out Solution: special memory to buffer image with scan-out synchronous to the raster. We call this the synchronous to the raster. We call this the framebufferframebuffer..

• Digital description to analog signal to digital displayDigital description to analog signal to digital display


PhosphersPhosphers• Flourescence:Flourescence: Light emitted while the phospher Light emitted while the phospher

is being struck by electronsis being struck by electrons

• Phospherescence:Phospherescence: Light emitted once the Light emitted once the electron beam is removedelectron beam is removed

• Persistence:Persistence: The time from the removal of the The time from the removal of the excitation to the moment when excitation to the moment when phospherescence has decayed to 10% of the phospherescence has decayed to 10% of the initial light outputinitial light output

PhosphersPhosphers• Flourescence:Flourescence: Light emitted while the phospher Light emitted while the phospher

is being struck by electronsis being struck by electrons

• Phospherescence:Phospherescence: Light emitted once the Light emitted once the electron beam is removedelectron beam is removed

• Persistence:Persistence: The time from the removal of the The time from the removal of the excitation to the moment when excitation to the moment when phospherescence has decayed to 10% of the phospherescence has decayed to 10% of the initial light outputinitial light output


RefreshRefresh

• Frame must be “refreshed” to draw new imagesFrame must be “refreshed” to draw new images

• As new pixels are struck by electron beam, others are As new pixels are struck by electron beam, others are decayingdecaying

• Electron beam must hit all pixels frequently to eliminate Electron beam must hit all pixels frequently to eliminate flickerflicker

• Critical fusion frequencyCritical fusion frequency

– Typically 60 times/secTypically 60 times/sec

– Varies with intensity, individuals, phospher persistence, Varies with intensity, individuals, phospher persistence, lighting...lighting...

RefreshRefresh

• Frame must be “refreshed” to draw new imagesFrame must be “refreshed” to draw new images

• As new pixels are struck by electron beam, others are As new pixels are struck by electron beam, others are decayingdecaying

• Electron beam must hit all pixels frequently to eliminate Electron beam must hit all pixels frequently to eliminate flickerflicker

• Critical fusion frequencyCritical fusion frequency

– Typically 60 times/secTypically 60 times/sec

– Varies with intensity, individuals, phospher persistence, Varies with intensity, individuals, phospher persistence, lighting...lighting...



• Interlaced ScanningInterlaced Scanning

• Assume can only scan 30 times / secondAssume can only scan 30 times / second

• To reduce flicker, divide frame into two “fields” To reduce flicker, divide frame into two “fields” of odd and even linesof odd and even lines


• Interlaced ScanningInterlaced Scanning

• Assume can only scan 30 times / secondAssume can only scan 30 times / second

• To reduce flicker, divide frame into two “fields” To reduce flicker, divide frame into two “fields” of odd and even linesof odd and even lines

1/30 Sec 1/30 Sec1/60 Sec 1/60 Sec 1/60 Sec 1/60 SecField 1 Field 1Field 2 Field 2

Frame Frame


CRT timingCRT timing

• Scanning (left to right, top to bottom)Scanning (left to right, top to bottom)

– Vertical Sync Pulse:Vertical Sync Pulse: Signals the start of the next field Signals the start of the next field

– Vertical Retrace:Vertical Retrace: Time needed to get from the bottom Time needed to get from the bottom of the current field to the top of the next fieldof the current field to the top of the next field

– Horizontal Sync Pulse:Horizontal Sync Pulse: Signals the start of the new Signals the start of the new scan linescan line

– Horizontal Retrace:Horizontal Retrace: The time needed to get from the The time needed to get from the end of the current scan line to the start of the next end of the current scan line to the start of the next scan linescan line

CRT timingCRT timing

• Scanning (left to right, top to bottom)Scanning (left to right, top to bottom)

– Vertical Sync Pulse:Vertical Sync Pulse: Signals the start of the next field Signals the start of the next field

– Vertical Retrace:Vertical Retrace: Time needed to get from the bottom Time needed to get from the bottom of the current field to the top of the next fieldof the current field to the top of the next field

– Horizontal Sync Pulse:Horizontal Sync Pulse: Signals the start of the new Signals the start of the new scan linescan line

– Horizontal Retrace:Horizontal Retrace: The time needed to get from the The time needed to get from the end of the current scan line to the start of the next end of the current scan line to the start of the next scan linescan line

What is a pixel?

Wood chips Chrome spheres TrashWood chips Chrome spheres Trash Wood chips Chrome spheres TrashWood chips Chrome spheres Trash

Daniel Rozin – NYU: (movies) http://fargo.itp.tsoa.nyu.edu/~danny/art.html

Display Technology: Color CRTs

Color CRTs are Color CRTs are muchmuch more complicated more complicated

• Requires manufacturing very precise geometryRequires manufacturing very precise geometry

• Uses a pattern of color phosphors on the screen:Uses a pattern of color phosphors on the screen:

• Why red, green, and blue phosphors?Why red, green, and blue phosphors?

Color CRTs are Color CRTs are muchmuch more complicated more complicated

• Requires manufacturing very precise geometryRequires manufacturing very precise geometry

• Uses a pattern of color phosphors on the screen:Uses a pattern of color phosphors on the screen:

• Why red, green, and blue phosphors?Why red, green, and blue phosphors?

Delta electron gun arrangement In-line electron gun arrangement

Delta electron gun arrangement

Display Technology: Color CRTs

Color CRTs haveColor CRTs have

• Three electron gunsThree electron guns

• A metal A metal shadow maskshadow mask to differentiate the beamsto differentiate the beams

Color CRTs haveColor CRTs have

• Three electron gunsThree electron guns

• A metal A metal shadow maskshadow mask to differentiate the beamsto differentiate the beams

Display Technology: Raster

Raster CRT pros:Raster CRT pros:

• Allows solids, not just wireframesAllows solids, not just wireframes

• Leverages low-cost CRT technology (i.e., TVs)Leverages low-cost CRT technology (i.e., TVs)

• Bright! Display Bright! Display emitsemits light light

Cons:Cons:

• Requires screen-size memory arrayRequires screen-size memory array

• Discreet sampling (pixels)Discreet sampling (pixels)

• Practical limit on size (call it 40 inches)Practical limit on size (call it 40 inches)

• BulkyBulky

• Finicky (convergence, warp, etc)Finicky (convergence, warp, etc)

Raster CRT pros:Raster CRT pros:

• Allows solids, not just wireframesAllows solids, not just wireframes

• Leverages low-cost CRT technology (i.e., TVs)Leverages low-cost CRT technology (i.e., TVs)

• Bright! Display Bright! Display emitsemits light light

Cons:Cons:

• Requires screen-size memory arrayRequires screen-size memory array

• Discreet sampling (pixels)Discreet sampling (pixels)

• Practical limit on size (call it 40 inches)Practical limit on size (call it 40 inches)

• BulkyBulky

• Finicky (convergence, warp, etc)Finicky (convergence, warp, etc)

CRTs – A Review

• CRT technology hasn’t changed much in 50 yearsCRT technology hasn’t changed much in 50 years

• Early television technologyEarly television technology

– high resolution high resolution

– requires synchronization between video signal and requires synchronization between video signal and electron beam vertical sync pulseelectron beam vertical sync pulse

• Early computer displaysEarly computer displays

– avoided synchronization using ‘vector’ algorithmavoided synchronization using ‘vector’ algorithm

– flicker and refresh were problematicflicker and refresh were problematic

• CRT technology hasn’t changed much in 50 yearsCRT technology hasn’t changed much in 50 years

• Early television technologyEarly television technology

– high resolution high resolution

– requires synchronization between video signal and requires synchronization between video signal and electron beam vertical sync pulseelectron beam vertical sync pulse

• Early computer displaysEarly computer displays

– avoided synchronization using ‘vector’ algorithmavoided synchronization using ‘vector’ algorithm

– flicker and refresh were problematicflicker and refresh were problematic

CRTs – A Review• Raster Displays (early 70s)Raster Displays (early 70s)

– like television, scan all pixels in regular patternlike television, scan all pixels in regular pattern

– use frame buffer (video RAM) to eliminate sync problemsuse frame buffer (video RAM) to eliminate sync problems

• RAMRAM

– ¼ MB (256 KB) cost $2 million in 1971¼ MB (256 KB) cost $2 million in 1971

– Do some math…Do some math…

- 1280 x 1024 screen resolution = 1,310,720 pixels1280 x 1024 screen resolution = 1,310,720 pixels

- Monochrome color (binary) requires 160 KBMonochrome color (binary) requires 160 KB

- High resolution color requires 5.2 MBHigh resolution color requires 5.2 MB

• Raster Displays (early 70s)Raster Displays (early 70s)

– like television, scan all pixels in regular patternlike television, scan all pixels in regular pattern

– use frame buffer (video RAM) to eliminate sync problemsuse frame buffer (video RAM) to eliminate sync problems

• RAMRAM

– ¼ MB (256 KB) cost $2 million in 1971¼ MB (256 KB) cost $2 million in 1971

– Do some math…Do some math…

- 1280 x 1024 screen resolution = 1,310,720 pixels1280 x 1024 screen resolution = 1,310,720 pixels

- Monochrome color (binary) requires 160 KBMonochrome color (binary) requires 160 KB

- High resolution color requires 5.2 MBHigh resolution color requires 5.2 MB

Movie Theaters

U.S. film projectors play film at 24 fpsU.S. film projectors play film at 24 fps• Projectors have a shutter to block light during frame advanceProjectors have a shutter to block light during frame advance

• To reduce flicker, shutter opens twice for each frame – To reduce flicker, shutter opens twice for each frame – resulting in 48 fps flashingresulting in 48 fps flashing

• 48 fps is perceptually acceptable48 fps is perceptually acceptable

European film projectors play film at 25 fpsEuropean film projectors play film at 25 fps• American films are played ‘as is’ in Europe, resulting in American films are played ‘as is’ in Europe, resulting in

everything moving 4% fastereverything moving 4% faster

• Faster movements and increased audio pitch are considered Faster movements and increased audio pitch are considered perceptually acceptableperceptually acceptable

U.S. film projectors play film at 24 fpsU.S. film projectors play film at 24 fps• Projectors have a shutter to block light during frame advanceProjectors have a shutter to block light during frame advance

• To reduce flicker, shutter opens twice for each frame – To reduce flicker, shutter opens twice for each frame – resulting in 48 fps flashingresulting in 48 fps flashing

• 48 fps is perceptually acceptable48 fps is perceptually acceptable

European film projectors play film at 25 fpsEuropean film projectors play film at 25 fps• American films are played ‘as is’ in Europe, resulting in American films are played ‘as is’ in Europe, resulting in

everything moving 4% fastereverything moving 4% faster

• Faster movements and increased audio pitch are considered Faster movements and increased audio pitch are considered perceptually acceptableperceptually acceptable

Viewing Movies at HomeFilm to DVD transferFilm to DVD transfer

• Problem: 24 film fps must be converted to Problem: 24 film fps must be converted to

– NTSC U.S. television interlaced 29.97 fps 768x494 NTSC U.S. television interlaced 29.97 fps 768x494

– PAL Europe television 25 fps 752x582PAL Europe television 25 fps 752x582

Use 3:2 PulldownUse 3:2 Pulldown

• First frame of movie is broken into first three fields (odd, even, odd)First frame of movie is broken into first three fields (odd, even, odd)

• Next frame of movie is broken into next two fields (even, odd)Next frame of movie is broken into next two fields (even, odd)

• Next frame of movie is broken into next three fields (even, odd, Next frame of movie is broken into next three fields (even, odd, even)…even)…

Film to DVD transferFilm to DVD transfer

• Problem: 24 film fps must be converted to Problem: 24 film fps must be converted to

– NTSC U.S. television interlaced 29.97 fps 768x494 NTSC U.S. television interlaced 29.97 fps 768x494

– PAL Europe television 25 fps 752x582PAL Europe television 25 fps 752x582

Use 3:2 PulldownUse 3:2 Pulldown

• First frame of movie is broken into first three fields (odd, even, odd)First frame of movie is broken into first three fields (odd, even, odd)

• Next frame of movie is broken into next two fields (even, odd)Next frame of movie is broken into next two fields (even, odd)

• Next frame of movie is broken into next three fields (even, odd, Next frame of movie is broken into next three fields (even, odd, even)…even)…

Display Technology: LCDs

Liquid Crystal Displays (LCDs)Liquid Crystal Displays (LCDs)

• LCDs: organic molecules, naturally in crystalline state, LCDs: organic molecules, naturally in crystalline state, that liquefy when excited by heat or E fieldthat liquefy when excited by heat or E field

• Crystalline state twists polarized light 90º. Crystalline state twists polarized light 90º.



• Crystalline state twists polarized light 90º. Crystalline state twists polarized light 90º.




• Crystalline state twists polarized light 90ºCrystalline state twists polarized light 90º



• Crystalline state twists polarized light 90ºCrystalline state twists polarized light 90º


Transmissive & reflective LCDs:Transmissive & reflective LCDs:

• LCDs act as light valves, not light emitters, and thus LCDs act as light valves, not light emitters, and thus rely on an external light source.rely on an external light source.

• Laptop screenLaptop screen

– backlitbacklit

– transmissive displaytransmissive display

• Palm Pilot/Game BoyPalm Pilot/Game Boy

– reflective displayreflective display

Transmissive & reflective LCDs:Transmissive & reflective LCDs:

• LCDs act as light valves, not light emitters, and thus LCDs act as light valves, not light emitters, and thus rely on an external light source.rely on an external light source.

• Laptop screenLaptop screen

– backlitbacklit

– transmissive displaytransmissive display

• Palm Pilot/Game BoyPalm Pilot/Game Boy

– reflective displayreflective display

Display Technology: Plasma

Plasma display panelsPlasma display panels

• Similar in principle to Similar in principle to fluorescent light tubesfluorescent light tubes

• Small gas-filled capsules Small gas-filled capsules are excited by electric field,are excited by electric field,emits UV lightemits UV light

• UV excites phosphorUV excites phosphor

• Phosphor relaxes, emits Phosphor relaxes, emits some other colorsome other color

Plasma display panelsPlasma display panels

• Similar in principle to Similar in principle to fluorescent light tubesfluorescent light tubes

• Small gas-filled capsules Small gas-filled capsules are excited by electric field,are excited by electric field,emits UV lightemits UV light

• UV excites phosphorUV excites phosphor

• Phosphor relaxes, emits Phosphor relaxes, emits some other colorsome other color

Display Technology

Plasma Display Panel ProsPlasma Display Panel Pros

• Large viewing angleLarge viewing angle

• Good for large-format displaysGood for large-format displays

• Fairly brightFairly bright

ConsCons

• ExpensiveExpensive

• Large pixels (~1 mm versus ~0.2 mm)Large pixels (~1 mm versus ~0.2 mm)

• Phosphors gradually depletePhosphors gradually deplete

• Less bright than CRTs, using more powerLess bright than CRTs, using more power

Plasma Display Panel ProsPlasma Display Panel Pros


• Good for large-format displaysGood for large-format displays

• Fairly brightFairly bright

ConsCons

• ExpensiveExpensive

• Large pixels (~1 mm versus ~0.2 mm)Large pixels (~1 mm versus ~0.2 mm)

• Phosphors gradually depletePhosphors gradually deplete

• Less bright than CRTs, using more powerLess bright than CRTs, using more power

Display Technology: DMD / DLP

Digital Micromirror Devices (projectors) or Digital Light ProcessingDigital Micromirror Devices (projectors) or Digital Light Processing

• Microelectromechanical (MEM) devices, fabricated with VLSI Microelectromechanical (MEM) devices, fabricated with VLSI techniquestechniques

Digital Micromirror Devices (projectors) or Digital Light ProcessingDigital Micromirror Devices (projectors) or Digital Light Processing

• Microelectromechanical (MEM) devices, fabricated with VLSI Microelectromechanical (MEM) devices, fabricated with VLSI techniquestechniques

Display Technology: DMD / DLP

DMDs are truly digital pixelsDMDs are truly digital pixels

Vary grey levels by modulating pulse Vary grey levels by modulating pulse lengthlength

Color: multiple chips, or color-wheelColor: multiple chips, or color-wheel

Great resolutionGreat resolution

Very brightVery bright

Flicker problemsFlicker problems

DMDs are truly digital pixelsDMDs are truly digital pixels

Vary grey levels by modulating pulse Vary grey levels by modulating pulse lengthlength

Color: multiple chips, or color-wheelColor: multiple chips, or color-wheel

Great resolutionGreat resolution

Very brightVery bright

Flicker problemsFlicker problems

Display Technologies: Organic LED ArraysOrganic Light-Emitting Diode (OLED) ArraysOrganic Light-Emitting Diode (OLED) Arrays

• The display of the future? Many think so.The display of the future? Many think so.

• OLEDs function like regular semiconductor LEDsOLEDs function like regular semiconductor LEDs

• But they emit lightBut they emit light

– Thin-film deposition of organic, light-emitting molecules Thin-film deposition of organic, light-emitting molecules through vapor sublimation in a vacuum.through vapor sublimation in a vacuum.

– Dope emissive layers Dope emissive layers with fluorescent with fluorescent molecules to create molecules to create color.color.

Organic Light-Emitting Diode (OLED) ArraysOrganic Light-Emitting Diode (OLED) Arrays

• The display of the future? Many think so.The display of the future? Many think so.

• OLEDs function like regular semiconductor LEDsOLEDs function like regular semiconductor LEDs

• But they emit lightBut they emit light

– Thin-film deposition of organic, light-emitting molecules Thin-film deposition of organic, light-emitting molecules through vapor sublimation in a vacuum.through vapor sublimation in a vacuum.

– Dope emissive layers Dope emissive layers with fluorescent with fluorescent molecules to create molecules to create color.color.

http://www.kodak.com/global/en/professional/products/specialProducts/OEL/creating.jhtml

Display Technologies: Organic LED Arrays

OLED pros:OLED pros:• TransparentTransparent

• FlexibleFlexible

• Light-emitting, and quite bright (daylight visible)Light-emitting, and quite bright (daylight visible)


• Fast (< 1 microsecond off-on-off)Fast (< 1 microsecond off-on-off)

• Can be made large or smallCan be made large or small

• Available for cell phones and car stereosAvailable for cell phones and car stereos

OLED pros:OLED pros:• TransparentTransparent

• FlexibleFlexible

• Light-emitting, and quite bright (daylight visible)Light-emitting, and quite bright (daylight visible)


• Fast (< 1 microsecond off-on-off)Fast (< 1 microsecond off-on-off)

• Can be made large or smallCan be made large or small

• Available for cell phones and car stereosAvailable for cell phones and car stereos

Display Technologies: Organic LED Arrays

OLED cons:OLED cons:• Not very robust, display lifetime a key issueNot very robust, display lifetime a key issue

• Currently only passive matrix displaysCurrently only passive matrix displays

– Passive matrix: Pixels are illuminated in scanline Passive matrix: Pixels are illuminated in scanline order, but the lack of phospherescence causes order, but the lack of phospherescence causes flickerflicker

– Active matrix: A polysilicate layer provides thin Active matrix: A polysilicate layer provides thin film transistors at each pixel, allowing direct pixel film transistors at each pixel, allowing direct pixel access and constant illum.access and constant illum.

OLED cons:OLED cons:• Not very robust, display lifetime a key issueNot very robust, display lifetime a key issue

• Currently only passive matrix displaysCurrently only passive matrix displays

– Passive matrix: Pixels are illuminated in scanline Passive matrix: Pixels are illuminated in scanline order, but the lack of phospherescence causes order, but the lack of phospherescence causes flickerflicker

– Active matrix: A polysilicate layer provides thin Active matrix: A polysilicate layer provides thin film transistors at each pixel, allowing direct pixel film transistors at each pixel, allowing direct pixel access and constant illum.access and constant illum.

Additional Displays

Display Walls (Princeton)Display Walls (Princeton)

Additional DisplaysStereoStereo

Video Controllers

Graphics HardwareGraphics Hardware

• Frame buffer is anywhereFrame buffer is anywherein system memoryin system memory


• Frame buffer is anywhereFrame buffer is anywherein system memoryin system memory

System Bus

CPU Video Controller

System Memory

Monitor

Frame bufferCartesian

Coordinates

Video Controllers


• Permanent place forPermanent place forframe bufferframe buffer

• Direct connection toDirect connection tovideo controllervideo controller


• Permanent place forPermanent place forframe bufferframe buffer

• Direct connection toDirect connection tovideo controllervideo controller

System Bus


System Memory Monitor

Frame bufferCartesian

Coordinates

FrameBuffer

Video Controllers

The need for The need for synchronizationsynchronizationThe need for The need for synchronizationsynchronization

System Bus



FrameBuffer

synchronized

Video Controllers

The need for The need for synchronizationsynchronization

• Double bufferingDouble buffering

The need for The need for synchronizationsynchronization

• Double bufferingDouble buffering

System Bus



DoubleBuffer

synchronized

previouscurrent

Raster Graphics Systems

DisplayProcessorDisplay

ProcessorSystemMemorySystemMemory

CPUCPU

FrameBufferFrameBuffer

MonitorVideoController

VideoController

System Bus

I/O Devices

Figure 2.29 from Hearn and Baker

Frame Buffer

Frame Buffer

Figure 1.2 from Foley et al.

Frame Buffer Refresh

Figure 1.3 from FvDFH Refresh rate is usually 30-75Hz

DAC

Direct Color Framebuffer

Store the actual intensities of R, G, and B individually in Store the actual intensities of R, G, and B individually in the framebufferthe framebuffer

24 bits per pixel = 8 bits red, 8 bits green, 8 bits blue24 bits per pixel = 8 bits red, 8 bits green, 8 bits blue

• 16 bits per pixel = ? bits red, ? bits green, ? bits blue

Store the actual intensities of R, G, and B individually in Store the actual intensities of R, G, and B individually in the framebufferthe framebuffer

24 bits per pixel = 8 bits red, 8 bits green, 8 bits blue24 bits per pixel = 8 bits red, 8 bits green, 8 bits blue

• 16 bits per pixel = ? bits red, ? bits green, ? bits blue

Color Lookup Framebuffer

Store indices (usually 8 bits) in framebufferStore indices (usually 8 bits) in framebuffer

Display controller looks up the R,G,B values before Display controller looks up the R,G,B values before triggering the electron gunstriggering the electron guns

Store indices (usually 8 bits) in framebufferStore indices (usually 8 bits) in framebuffer

Display controller looks up the R,G,B values before Display controller looks up the R,G,B values before triggering the electron gunstriggering the electron guns

Frame Buffer

DACPixel color = 14

Color LookupTable

0

1024

14R G B

A Graphics System

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