Chapter-2 Overview of Graphics Systems Topics: Topics: Video-display system Video-display system...

Chapter-2Chapter-2Overview of Graphics SystemsOverview of Graphics Systems

Topics:Topics:

Video-display systemVideo-display system Rater Scan systemsRater Scan systems Random scan systemsRandom scan systems Graphic monitors and workstationsGraphic monitors and workstations Input devicesInput devices Hard-copy devicesHard-copy devices Graphics SoftwareGraphics Software

Video-Display DevicesVideo-Display DevicesRefresh Cathode-Ray TunesRefresh Cathode-Ray Tunes

Fig.2-2 Basic design of a magnetic-deflection CRT

Video-Display DevicesVideo-Display DevicesRefresh Cathode-Ray TunesRefresh Cathode-Ray Tunes

Fig.2-3 Operation of an electron gun with an accelerating anode.

Video-Display DevicesVideo-Display DevicesRefresh Cathode-Ray TunesRefresh Cathode-Ray Tunes

Fig.2-4 Electrostatic deflection of the electron beam in a CRT

Video-Display DevicesVideo-Display DevicesIllumination of phosphor spots on back of Illumination of phosphor spots on back of

CRTCRT

Video-Display DevicesVideo-Display DevicesFig.2-7 A raster –scan system displays an object as Fig.2-7 A raster –scan system displays an object as

a set of discrete points across each scan line.a set of discrete points across each scan line.

Video-Display DevicesVideo-Display DevicesNote at the Interlace mechanism of display: display the even

lines in1/60 of a second and then display the odd lines in next 1/60

seconds.

Video-Display DevicesVideo-Display DevicesFig.2-9 A random-scan system draws the component lines of Fig.2-9 A random-scan system draws the component lines of

an object in any order specified.an object in any order specified.

Video-Display DevicesVideo-Display Devices

Fig.2-10 Operation of a delta-delta, shadow-mask CRT. Three Fig.2-10 Operation of a delta-delta, shadow-mask CRT. Three electron guns, aligned with the triangular color-dot patterns electron guns, aligned with the triangular color-dot patterns

on the screen, on the screen, are directed to each dot triangle by a shadow mask.are directed to each dot triangle by a shadow mask.

Flat panel displaysFlat panel displaysFig.2-11 Basic design of a plasma-panel display Fig.2-11 Basic design of a plasma-panel display

device.device.

Applying voltages to a pair of horizontal and vertical conductors causes the gas at the intersection of two conductors to break down into a glowing

plasma of electron and ions.

Flat panel displaysFlat panel displaysA plasma-panel display with a resolution of 2048 x A plasma-panel display with a resolution of 2048 x

2048 and a screen diameter of 1.5 meters.2048 and a screen diameter of 1.5 meters.

Flat panel displaysFlat panel displaysBasic design of a thin-film electro-luminescentBasic design of a thin-film electro-luminescent

display device. display device.

Liquid-crystal displays (LCD)Liquid-crystal displays (LCD)Laptops use LCD display mechanism with different Laptops use LCD display mechanism with different

resolutions and different number of colors.resolutions and different number of colors.

How a Liquid-crystal displays (LCD) How a Liquid-crystal displays (LCD) works.works.

By twisting the LCD Nematics, the polarized light passed By twisting the LCD Nematics, the polarized light passed through the horizontal conductor will twist and pass through through the horizontal conductor will twist and pass through

the vertical conductor.the vertical conductor.

This is how one pixelBecomes visible.

To turn off a pixel, theLCD Nematics will beForced to becomeParallel.

This is done by applyingA voltage to bothHorizontal and verticalconductors.

The screen is refreshedin the rate of 60 frames per secondAs in emissive devices.

Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems

Fig.2-19 Viewing a stereoscopic projection.Fig.2-19 Viewing a stereoscopic projection.

Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems

Fig.2-20 A stereoscopic viewing pair.Fig.2-20 A stereoscopic viewing pair.

Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems

Fig.2-21 Glasses for viewing a stereoscopic scene Fig.2-21 Glasses for viewing a stereoscopic scene and an infrared synchronizing emitter.and an infrared synchronizing emitter.

Stereoscopic and Virtual-Reality Stereoscopic and Virtual-Reality SystemsSystems

Fig.2-22 A headset used in virtual-reality systemFig.2-22 A headset used in virtual-reality system

Interacting with a virtual-reality Interacting with a virtual-reality environment.environment.

Use of head-set, data gloves and a set of cords to Use of head-set, data gloves and a set of cords to transfer the data to a host computer.transfer the data to a host computer.

Fig.2-24 An ultrasound tracking device Fig.2-24 An ultrasound tracking device used with stereoscopic glass to track head used with stereoscopic glass to track head

position.position.

Raster-scan systemRaster-scan systemFig.2-25 The architecture of a simple raster graphics Fig.2-25 The architecture of a simple raster graphics

system.system.

Raster-scan systemRaster-scan systemFig.2-26 Architecture of a raster system with a fixed portion Fig.2-26 Architecture of a raster system with a fixed portion

of the system memory reserved for the frame buffer.of the system memory reserved for the frame buffer.

Raster-scan systemRaster-scan system

Raster-scan systemRaster-scan system

Fig.2-28 Basic video-controller refresh operations.

Raster-scan systemRaster-scan system

Fig. 2-29 Architecture of a raster-graphics system with a display processor.

How characters are displayed on aHow characters are displayed on aRaster-scan systemRaster-scan system

Limits in size, font type, etc.Possibilities to save fonts of differentSizes without the need to save a large bitmap.

Random-scan systemsRandom-scan systems

Fig.2-32 Architecture of a simple random-scan system.

Graphics monitors and work-Graphics monitors and work-stationsstations

Fig.2-35 A very high-resolution (2560 x 2048) color monitor for Air traffic control application.

Graphics monitors, A Media-WallGraphics monitors, A Media-Wall

Fig.2-36 The Media-Wall: A multi-screen display system. An image displayed on a 3-by-3 array of monitors.

Applications in Airports, and places that we need to have live announcements.

Graphics monitors and work-Graphics monitors and work-stationsstations

Multiple work-stations for a CAD Multiple work-stations for a CAD group.group.

An artist’s work-station, featuring a color raster An artist’s work-station, featuring a color raster monitor, graphic tablet with hand cursor, a light monitor, graphic tablet with hand cursor, a light

tablet.tablet.

Fig.2-42, Z mouse is used to displace Fig.2-42, Z mouse is used to displace objects in 3D space.objects in 3D space.

The Z mouse features 3 buttons, a mouse ball underneath,

a thumbwheel on the side, and a track ball on top.

Digitizers.Digitizers.Fig.2-46, The Summa-Sketch III desktop tablet with Fig.2-46, The Summa-Sketch III desktop tablet with

a 16 button hand cursor.a 16 button hand cursor.

Digitizers.Digitizers.The Microgrid III tablet with 16 button hand cursor, The Microgrid III tablet with 16 button hand cursor,

designed for digitizing larger drawings.designed for digitizing larger drawings.

Digitizers.Digitizers.Fig.2-48 The NotePad desktop tablet with stylus.Fig.2-48 The NotePad desktop tablet with stylus.

This devise is used forOn line signature input,On line handwriting input

And On-line drawing inputto a PC.

Some models of it can sense pressure, speed,and the direction ofpressure.

This is a perfect devisefor on line signature recognition.

Digitizers.Digitizers.

Fig.2-49 An artist’s digitizer system, with a pressure sensitive Cordless stylus.

Digitizers.Digitizers.Fig.2-50 A 3D digitizing system for use with Fig.2-50 A 3D digitizing system for use with

Apple Macintosh computers.Apple Macintosh computers.

Image ScannersImage ScannersFig.2-52 (Right) Drum scanner with a selectable Fig.2-52 (Right) Drum scanner with a selectable

resolution from 50 to 4000 dots per inch.resolution from 50 to 4000 dots per inch.

ScannerScannerFig. 2-53 A large floor-model scanner used to scan Fig. 2-53 A large floor-model scanner used to scan

architectural and engineering drawings up to architectural and engineering drawings up to 40 inches wide and 100 feet long.40 inches wide and 100 feet long.

Touch ScreensTouch ScreensFig. 2-54 Plasma panels with touch screens.Fig. 2-54 Plasma panels with touch screens.

How does a touch screen works.How does a touch screen works.

An optical touch panel, showing the arrangement of infrared LED units and detectors around the edges of

the frame.

Light PensLight Pens

Fig.2-56 A light pen activated with a button switch.

A speech-recognition systemA speech-recognition system

Hard copy devicesHard copy devicesA picture generated on a dot-matrix printer.A picture generated on a dot-matrix printer.

Note how the density of the dot patterns can be varied to Note how the density of the dot patterns can be varied to produce light and dark areas.produce light and dark areas.

Hard copy devicesHard copy devices

Fig.2-61 Floor model, ink-jet color printers that use variable dot size to achieve an equivalent resolution of 1500 to 1800 dots per inch.

Hard copy devices used to print Hard copy devices used to print large posterslarge posters

An electrostatic printer that can display 400 dots per inch.

Pen PlottersPen Plotters

Fig.2-63, A desk-top pen plotter with a resolution of 0.025 mm.

Pen PlottersPen Plotters

Fig.2-64 A large, roll-feed pen plotter with automatic multicolor 8-pen charger and a resolution of 0.0127 mm.

Graphics Software,Graphics Software,Coordinate representation. Note at different levels of Coordinate representation. Note at different levels of

transformation before an object is actually displayed on transformation before an object is actually displayed on monitor.monitor.