Post on 18-Jan-2016
Video output and image input devices
Unit objectives: Explain how CRT and LCD display
devices produce images Install and configure digital cameras
Topic A
Topic A: Monitors Topic B: Cameras
CRT monitor
Three electron beams– Red– Green– Blue
Also called RGB monitors
Beams pass through horizontal and vertical deflection coils
Focused by a magnetic yoke
CRT components
Cathode Anode Phosphors Electronic beam positioning
– Shadow mask– Aperture grill– Slotted mask
Flyback transformer
How CRTs produce images
Degaussing
Powerful magnets can magnetize the mask
Causes misalignment of dot focus Degaussing button demagnetizes
monitor Most monitors degauss automatically
when turned on Repeated degaussing can damage a
CRT
CRT characteristics
Screen size Aspect ratio Resolution Refresh rate Dot pitch Flat or curved screen
Activity A-1
Choosing a CRT monitor
Video connectors
15-pin D-sub Male to female
Display properties
Screen resolution Color quality Monitor settings Color depth
Display adjustments
Brightness Contrast Position of image on screen Adjustment method varies by monitor
Safety
Never open a monitor Requires special training Use care when lifting
– Balanced stance– Squat close to floor– Lift with legs– Grip with entire hand
Interference– Magnets– Fluorescent lights– Heavy machinery
Activity A-2
Using a CRT monitor
Flat-panel monitor
Used to be found only in laptops
Liquid crystal display Thin-film transistor
(TFT) technology Same technology as
digital watches & calculators
Crystals aligned with electric current
Don’t confuse with flat-screen CRT
LCD advantages
Less power used Less heat generated Less desk space required for the
same size viewable area Less glare produced Less radiation emitted
Display technology
Active-matrix TFT Liquid crystals Pixels and subpixels Older technologies
– Passive matrix– Dual scan
Flat-panel monitor characteristics
Screen size Viewing angle Response rate Contrast ratio Native resolution
– XGA — 1024×768 pixels– SXGA — 1280×1024 pixels– UXGA — 1600×1200 pixels– WXGA+ — 1440×900 pixels– WSXGA+ — 1680×1050 pixels– WUXGA — 1920×1200 pixels
continued
Flat-panel characteristics, continued
Brightness Other features
– Change orientation– Built-in speakers– USB hub– Anti-theft lock– Wall mounting
Specifications for wall mounting at vesa.org/VESAFDMIPR.htm
Touch screen
Touch-sensitive surface– Pressure-sensitive resistors– Infrared sensors– Electronic capacitors
Uses– PDAs– Point-of-sale terminals– Bank ATMs
Input– Stylus– Finger
Touch-screen input
Methods– Additional layer with electrical current– Capacitors between layers– Acoustic waves
Takes place of mouse Connections can be damaged by too
much pressure or sharp object Requires calibration
Laptop monitors
LCD Some plasma Connections:
– Ribbon cable connects screen to video card– Cable connects screen to inverter
Inverter regulates power to fluorescent lamps in LCD panel
Integrated or separate graphics cards Might have own memory or share memory
Activity A-3
Choosing an LCD monitor
Flat-panel monitor connections
Connected via analog or digital connectors
Connection types– 15-pin VGA-style connection cable– DVI-D– DVI-I
TMDS Transition Minimized Differential Signaling Protocol used to transmit data to digital
monitor No analog conversion Single-link cables use one TDMS
transmitter Dual-link cables use two TDMS transmitters Supported resolutions
– Single-link up to 1920×1200– Dual-link up to 2560×1600
LCD monitor installation
1. Determine the type of video connection
2. If DVI connection, determine the type of DVI cable
3. If no DVI connection, can install a graphics adapter with DVI connectors
Multiple monitors
Configure multiple monitors in Windows
Display projectors
Show computer screen to large groups Useful for meetings and classrooms Connect using
– VGA– S-Video– Composite– USB– Serial
DisplayPort technology
New specification developed by VESA Covers
– Displays CRT LCD Plasma Projection
– Connections PCs Game systems DVD players Other image sources
Activity A-4
Using an LCD monitor
Topic B
Topic A: Monitors Topic B: Cameras
Digital cameras
Popular devices Quality of picture expressed in
megapixels (MP) Cameras available from 1 MP to over
8 MP
Resolutions
MP Good forMax print size (in.) Found in
Under 1 Broadcasting over the Internet
Web cameras (webcams)
1 to 2 E-mailing 4×6 Camera phones; still photos shot on digital video cameras; older digital cameras
3 to 4 Printing; e-mailing; using on Web if you crop image
5×7 High-end camera phone; low-end consumer-grade digital cameras
5 to 8 Large prints 8×10 Mid-range consumer grade
Over 8 Professional use; very large prints
11×14 and larger
Prosumer and professional-grade digital cameras
Digital camera memory cards
CompactFlash Memory Stick Secure Digital SmartMedia xD-Picture Card
Memory cards
CompactFlash memory cards: same physical size, but different capacities
Memory stick SD card
Printing images
No film development costs Store and view photos on computer Print at home Print at store Home prints aren’t same quality as
store’s
Digital camera connections
Still cameras: USB Video camera: USB or IEEE 394 Devices run on batteries
– Rechargeable– Disposable– If disposable, use digital-rated
Card readers– Built in– External device
Memory card readers
Activity B-1
Connecting a digital camera
Web cameras
Specialized cameras – Designed to record live video – Transmit it across a network or the Internet– Transmit live or pre-recorded
Might include:– Built-in microphones – Software for video e-mail, video capture,
videoconferencing, and still-image capture
Capture video at relatively low resolutions, typically one MP or less
Connected to a PC – Usually through USB
Webcam example
Network cameras
Also called “IP cameras” Designed for Web-based video distribution
– Sometimes includes audio
Don’t need to be connected to PC Includes:
– Network port supporting wired or wireless Ethernet
– Embedded software
Might include:– Limited Web server software
Network camera example
Network camera uses
Live video feeds – Also called “live webcams”
Security cameras– Detects motion– Sends alert/e-mail
Headsets, microphones, and speakers
Integrated microphone Can use computer’s speakers Headset for better call quality
Connection software
Need to connect to a service provider such as Skype or Vonage
Often at no charge Use installation & configuration
instructions on provider’s Web site
Activity B-2
Making a video call with Skype
Unit summary
Explained how CRT and LCD display devices produce images
Installed and configured digital cameras