Chapter 4.1 & 4.2

High-Def Pictures

A digital camera can take pictures that use from 4 to 20 million dots (pixels) to make the picture. The more dots it uses, the sharper the image is. But more dots also take up more space on the memory card where the pictures are stored in the camera. Photographers can choose to take photos of lesser quality to save space. They can also delete photos from the camera's memory to make space for new ones.

3-D Glasses

A similar but larger device is the Cave Automated Virtual Environment, or CAVE. The is a room in which three-dimensional images are shown on the floor, walls, and ceiling. A person in the room wears 3-D glasses. The glasses and images create the illusion of interacting in three-dimension.

sound card

A sound card is a circuit board that processes sounds in multiple ways. First, it digitizes sounds by changing them from analog to digital form. Then, it processes the digital sounds by following a set of built-in instructions. For example, it can prepare the digital sound files for use with voice recognition software. Sometimes the sound card reduces the size of sound files by compressing the data. That way, the files take up less space in memory. Finally, the sound card reverses the digitizing process so you can play analog sounds through the computer's speakers.

Harmful Screens?

Another new technology might help users of small video screen to see better in sunlight. OLED or organic light emitting diode, technology consumes less power and produces better displays that current LCD screens. OLED screens also have very good video quality - the manufacturers call it "full motion" video.

Scanners

Any printed document can be digitized by using a scanner. Scanners shine a light onto the material to be copied and change the image into pixels. This creates a digital image that can be input. Most scanners have optical character recognition, or OCR, software. When you scan printed text using this software, the text is turned into a digital file. In this way, you can input printed text, including handwriting, without having to type it.

Outputting Video

Data Projectors You may be familiar with data projectors, which show a computer's video output on a projection screen, so many people can view it at once. These projectors are often used to display presentations for educational or business meetings. Digital light processing, or DLP, projectors use millions of tiny mirrors to create a very sharp image. That image is then projected through a lens and onto a screen. Because the image they produce is so sharp, DLP projectors can be used with large audiences. They can even be used in brightly lit rooms.

Outputting Video

Headsets A headset, which has two LCD panels, is worn over the head. The computer sends video images to each panel. To the person wearing the headset, it seems as if he or she is walking in a three-dimensional space.

Even Better Than Virtual Reality!

One new technology goes beyond headsets and CAVEs to combine computer and people. Army researchers are trying to develop a special suit. Run by computers and guided by the wearer, the suit will include simple machines such as pistons. If it works, the suit will greatly increase the speed and strength of the person wearing it. Having powerful arms, for example, could be helpful during rescue operations.

Different Printers

Recall that image quality varies based on which type of printer is used to output an image. Both impact and nonimpact printers create images by printing tiny dots on the paper. Inject and laser printers have much higher print quality. Therefore, they are ore often used for printing graphic images. The best printer for printing color images is a thermal transfer printer. These printers use heat to transfer color dyes or inks onto paper. Thermal transfer printers do not make pictures out of tiny dots. Instead, the colors actually blend together on the paper. These printers only work with glossy paper.

Scientific Cameras

Scientists use an input device called a sensor to record many different kinds of data. Sensors can detect physical phenomenon, such as humidity, air pressure, and temperature.

Special Video Adapters

Some video adapters send images to the monitor very quickly. They are called video accelerators. Most computers today have highly specialized video adapters, called 3-D video adapters. Images on a monitor have only two dimensions - height and width. 3D video adapters add a third dimension to an image - depth.

Outputting Video

Televisions Some devices let you send video from a computer to a television. As high-definition television, or HDTV, has become more widely used, more people are using their television as an output device. HDTV uses only digital audio and video and produces a much sharper image than regular television.

Video Adapters

The images you see on your monitor are created by a video adapter. The adapter is a circuit board that receives data from an operating system or software application. It changes that data into electrical currents and sends them to the monitor. In a color monitor, the amount of current sent by the video adapter determines the color the monitor will produce. Like a sound card, a video adapter processes data so that the computer's CPU can take care of other jobs. It also has its own memory, called video memory, or VRAM, to free up spaces in the computer's memory.

Illegal Movie Copying

There is another use for video capture that is strictly illegal. Some computer users digitize movies, pay-per-view events, and television shows and post them on Web sites. People can visit the sites, download the shows, and watch them for free. This breaks copyright law, which protects the rights of people who create works of art, such as books, songs, and movies.

Outputting Sound

To output sound to headphones or speakers, your computer must have a sound card and speakers. The sound card changes digital sound files stored in the computer's memory into an electrical current. It sends that current to the speakers to produce audio output. The sound a computer can produce depends on the computer's software. Two kinds of software allow audio output: Speech synthesis software allows the computer to read text files aloud. Musical instrument digital interface (MIDI) software allows the computer to create music. With this software, you can send instructions to a digital musical instrument called a synthesizer. This device then sounds the notes it has been instructed to play.

Different types of scanners

With a sheetfed scanner, you insert the pages you want copied and the scanner pulls them through one at a time. • Flatbed scanners work more like copy machines. You lay material on a at glass panel to make the copy. All-in-one printers have flatbed scanner capability. • Handheld scanners are portable models that you hold in your hand. They are useful for copying small originals.

Inputting Video

You can input and display full-motion video and animation on a computer. Like all other forms of input, the videos must be in digital form. Digital video cameras record moving images in digital form. Most smart phones can record video, too. To convert analog videos to digital format, a computer needs a video capture card. Like a sound card, this type of circuit board changes video images into a digital file. These cards also compress files, so they occupy less disk space. 

fax machine

or facsimile machine, scans printed documents and sends them over phone lines to another fax machine. Though fax machines are still used by some companies, many documents that were once sent as a fax are now sent online as image files.

digital camera

takes pictures. In a traditional camera, light enters the lens and strikes a piece of film coated with chemicals that are sensitive to light. The chemicals produce an image on the film. In a digital camera, a computer chip takes the information from the lens and records it as pixels, or small dots, that form the image. A digital camera has memory to store the pictures you take. Some digital cameras store images on a memory card that can be removed.

microphone

the most basic device for inputting sound into a computer. You use it for all types of sound, including music, narration, and speech for voice recognition software. Microphones capture sounds in analog form—as a series of rapidly changing waves or vibrations. To be usable by a computer, sounds must be in digital form, that is, the waves must be converted to binary code (1s and 0s) that the computer can recognize. The sound card does this work.