3-D and Holographic Imaging
Holography is a technology that allows the production of 3-D images
(holograms).
The process involves:
• A source of laser light.
• Interference of light.
• Light diffraction.
• Light intensity recording.
How it works:
1. The laser beam is split into two beams:
- Object beam: Reflected off the object onto a photographic plate.
- Reference beam: Reflected off mirrors and combined with the object beam
on the photographic plate.
2. As the holographic image rotates, it appears 3-D, mimicking the original
object's movement.
Applications of Holography
• Engineering design (CAD) – allows 3-D designs.
• Architecture – enables design through 360 degrees.
• Simulations.
• Medical imaging (linked to tomography and 3-D printing).
• Cinema (special effects).
• Gaming (special effects).
• Advertising.
• Holographic televisions (expected by 2025, providing 3-D experiences
without glasses).
• Holographic computer memories (optical storage capable of storing 1 TB
in a small crystal).
• Optical computers (expected to operate trillions of times faster than
current technology).
Virtual Reality
• Virtual reality (VR) creates an artificial environment through software.
• Users interact with this environment using devices like goggles, sensor suits,
gloves, or helmets to feel immersed in the experience.
Uses of Virtual Reality
• Military applications – for example, training with new equipment like tanks.
• Education – viewing ancient buildings or historical reconstructions.
• Healthcare – for diagnostic purposes.
• Entertainment – enhancing the realism in games using VR gear.
• Fashion – previewing clothing and fashion shows virtually.
• Heritage – exploring historical sites.
• Business – training and scenario-based learning.
• Real estate – virtual tours of houses.
• Engineering – visualizing new designs.
• Sports – improving techniques through virtual feedback.
• Media – creating special effects in films.
• Scientific visualization – for example, studying molecular structures in
chemistry.
INPUT AND OUTPUT DEVICES (New topic)
Input Devices and Their Uses
Input devices are hardware tools that allow data to be entered into a
computer. They range from common tools like keyboards to more specialized
devices like barcode readers.
Keyboards
Keyboards are among the most common input devices, typically using a
QWERTY layout.
Types of keyboards
• Ergonomic Keyboards: Designed to minimize health-related issues such as
carpal tunnel syndrome and repetitive strain injury (RSI).
Uses
• Inputting data into applications (text processors, spreadsheets).
• Executing commands (e.g., Print Screen, Ctrl+P to print).
Advantages
a. Quick text entry.
b. User-friendly for most.
c. Immediate feedback as data is compared on-screen.
Disadvantages
a. Difficult for users with limited arm/wrist mobility.
b. Slower than direct data entry methods like optical mark recognition.
c. Occupies significant desk space.
Concept Keyboard
• Uses icons or phrases instead of letters. Each key represents a specific
action or item.
Applications
a. Fast-food restaurants for item selection.
b. Unmanned information kiosks as they are tamper-resistant and can handle
various environmental conditions.
Advantages
• No need for full typing, just key presses.
• Waterproof and tamper-resistant.
Numeric Keypads
Uses
a. ATMs for PIN entry.
b. Mobile phones for quick numeric input.
c. Point-of-sale terminals for when barcode readers fail.
Advantages
a. Faster than full keyboards for numeric data.
b. Compact and portable.
Disadvantages
a. Small keys can be challenging to use.
b. Non-intuitive number arrangement for some users.
Pointing Devices
Mouse
• A mouse is a type of pointing device that controls the position of a pointer
on the computer screen by moving the mouse.
Buttons:
• Left button: Typically used for selecting items or double-clicking to open
them.
• Right button: Brings up context menus.
• Many mice also feature a scroll button for navigating through documents
or web pages more quickly.
Types of Mice
1. Optical Mouse
• Detects movement through reflected light rather than a moving ball.
• Advantages: No moving parts, more robust, does not collect dirt,
performs better on most surfaces.
2. Cordless/Wireless Mouse
• Transmits signals to a USB receiver plugged into the computer.
• Advantages: Freedom of movement without cables.
Uses
• Opening, closing, and minimizing software.
• Grouping, moving, and deleting files.
• Image editing: Adjusting the size and position of drawings or images in
documents.
• Controlling the pointer for selecting icons, menus, and scrolling in any
direction.
Advantages
• Faster and easier to choose options than using a keyboard.
• Quick navigation through applications and the internet.
• Requires less desk space compared to a keyboard.
Disadvantages
• Challenging for users with restricted hand or wrist movement.
• Older mice with moving parts can get clogged with dirt, leading to poor
performance.
• Requires a flat surface to function effectively, which can be a challenge
in certain environments like on an airplane.
Touchpad (Nxt Lesson)
