Chapter-2
Overview of Graphics Systems
Topics:
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Video-display system
Rater Scan systems
Random scan systems
Graphic monitors and workstations
Input devices
Hard-copy devices
Graphics Software
Video-Display Devices
Refresh Cathode-Ray Tunes
Fig.2-2 Basic design of a magnetic-deflection CRT
Video-Display Devices
Refresh Cathode-Ray Tunes
Fig.2-3 Operation of an electron gun with an accelerating anode.
Video-Display Devices
Refresh Cathode-Ray Tunes
Fig.2-4 Electrostatic deflection of the electron beam in a CRT
Video-Display Devices
Illumination of phosphor spots on back of CRT
Video-Display Devices
Fig.2-7 A raster –scan system displays an object as a set
of discrete points across each scan line.
Video-Display Devices
Note at the Interlace mechanism of display: display the even lines in
1/60 of a second and then display the odd lines in next 1/60 seconds.
Video-Display Devices
Fig.2-9 A random-scan system draws the component lines of an
object in any order specified.
Video-Display Devices
Fig.2-10 Operation of a delta-delta, shadow-mask CRT. Three electron
guns, aligned with the triangular color-dot patterns on the screen,
are directed to each dot triangle by a shadow mask.
Flat panel displays
Fig.2-11 Basic design of a plasma-panel display 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 displays
A plasma-panel display with a resolution of 2048 x 2048
and a screen diameter of 1.5 meters.
Flat panel displays
Basic design of a thin-film electro-luminescent
display device.
Liquid-crystal displays (LCD)
Laptops use LCD display mechanism with different
resolutions and different number of colors.
How a Liquid-crystal displays (LCD) works.
By twisting the LCD Nematics, the polarized light passed through the
horizontal conductor will twist and pass through the vertical conductor.
This is how one pixel
Becomes visible.
The screen is refreshed
in the rate of
60 frames per second
As in emissive devices.
To turn off a pixel, the
LCD Nematics will be
Forced to become
Parallel.
This is done by
applying
A voltage to both
Horizontal and vertical
conductors.
Stereoscopic and Virtual-Reality Systems
Fig.2-19 Viewing a stereoscopic projection.
Stereoscopic and Virtual-Reality Systems
Fig.2-20 A stereoscopic viewing pair.
Stereoscopic and Virtual-Reality Systems
Fig.2-21 Glasses for viewing a stereoscopic scene and an
infrared synchronizing emitter.
Stereoscopic and Virtual-Reality Systems
Fig.2-22 A headset used in virtual-reality system
Interacting with a virtual-reality environment.
Use of head-set, data gloves and a set of cords to transfer the
data to a host computer.
Fig.2-24 An ultrasound tracking device used with
stereoscopic glass to track head position.
Raster-scan system
Fig.2-25 The architecture of a simple raster graphics system.
Raster-scan system
Fig.2-26 Architecture of a raster system with a fixed portion of the
system memory reserved for the frame buffer.
Raster-scan system
Raster-scan system
Fig.2-28 Basic video-controller refresh operations.
Raster-scan system
Fig. 2-29
Architecture of a raster-graphics system with a display processor.
How characters are displayed on a
Raster-scan system
Limits in size, font type, etc.
Possibilities to save fonts of different
Sizes without the need to save
a large bitmap.
Random-scan systems
Fig.2-32 Architecture of a simple random-scan system.
Graphics monitors and work-stations
Fig.2-35 A very high-resolution (2560 x 2048) color monitor
for Air traffic control application.
Graphics 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-stations
Multiple work-stations for a CAD group.
An artist’s work-station, featuring a color raster monitor,
graphic tablet with hand cursor, a light tablet.
Fig.2-42, Z mouse is used to displace
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.
Fig.2-46, The Summa-Sketch III desktop tablet with a 16
button hand cursor.
Digitizers.
The Microgrid III tablet with 16 button hand cursor,
designed for digitizing larger drawings.
Digitizers.
Fig.2-48 The NotePad desktop tablet with stylus.
This devise is used for
On line signature input,
On line handwriting input
And On-line drawing input
to a PC.
Some models of it can
sense pressure, speed,
and the direction of
pressure.
This is a perfect devise
for on line signature
recognition.
Digitizers.
Fig.2-49 An artist’s digitizer system, with a pressure sensitive
Cordless stylus.
Digitizers.
Fig.2-50 A 3D digitizing system for use with
Apple Macintosh computers.
Image Scanners
Fig.2-52 (Right) Drum scanner with a selectable
resolution from 50 to 4000 dots per inch.
Scanner
Fig. 2-53 A large floor-model scanner used to scan
architectural and engineering drawings up to
40 inches wide and 100 feet long.
Touch Screens
Fig. 2-54 Plasma panels with touch screens.
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 Pens
Fig.2-56 A light pen activated with a button switch.
A speech-recognition system
Hard copy devices
A picture generated on a dot-matrix printer.
Note how the density of the dot patterns can be varied to produce light
and dark areas.
Hard 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 large
posters
An electrostatic printer that can display 400 dots per inch.
Pen Plotters
Fig.2-63, A desk-top pen plotter with a resolution of 0.025 mm.
Pen 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,
Coordinate representation. Note at different levels of transformation
before an object is actually displayed on monitor.