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