Four other types of input devices are audio-input devices, video-input devices, sensors, electronic cameras, and human biology input device. Audio input devices may digitize sound by means of an audio board or a MIDI board. Video input devices may use frame grabber or full motion video cards. Electronic cameras are still video or digital cameras; the latter use light sensitive silicon chips to capture photographic images. Sensors collect specific kinds of data directly from the environment.
Here I describe four types:
Voice recognition devices are only one kind of audio input, which can include music and other sounds. An audio input device records of plays analog sounds and translates it for digital storage and processing. An analog sound signal represents a continuously variable wave within a certain frequency range. Such continuous fluctuations are usually represented with an analog device such as a cassette player. For the computer to process them, these variable waves must be converted to digital 0s and 1s, the language of the computer.
There are two ways in which audio is digitized:
Audio board: analog sound from, say, a cassette player goes through a special circuit board called an audio board. An audio board is an add-on circuit board in a computer that converts analog sound to digital sound and stores it for further processing.
MIDI board: a MIDI board- MIDI stands for Musical Instrument Digital interface- is an add-on board that creates digital music. That is, the music is created in digital form as the musician performs, for example, on a special MIDI keyboards. The principal use of audio input devices such as these is to provide digital input for multimedia PCs. A multimedia system is a microcomputer that incorporates text, graphics, sound video, and animation is a single digital presentation.
As with sound, most film and videotape is in analog form, with the signal a continuously variable wave. Thus, to be used by a computer, the signals that come from a VCR or a camcorder must be converted to digital form through a special video card installed in the computer. Two types of video cards are the frame grabber video and the full motion video: Frame grabber video card: some video cards, called frame grabbers, can capture and digitize only a single frame at a time. Full motion video card: other video cards: other video cards, called full motion video cards, can convert analog to digital signals at the rate of 30 frames per second, giving the effect of a continuously flowing motion picture. The main limitation in capturing full video is not input but storage. It takes a huge amount space to store just 1 second of video.
A sensor is a type of input device that collects specific kinds of data directly from the environment and transmits it to a computer. Although you are unlikely to see such input devices connected to a PC in an office, they exist all around us, often in invisible form. Sensors can be used for detecting all kinds of thing: speed, movement, weight, pressure, temperature, humidity, wind, and current, fog, gas, smoke, light, shapes, images, and so on.
Beneath the pavement, for example, are sensors that detect the speed and volume of traffic. These sensors send data to computers that can adjust traffic lights cars and trucks away from gridlocked areas. In aviation, sensors are used to detect ice buildup on airplane wings or to alert pilots to sudden changes in wind direction. In California, sensors have been planted along major earthquake fault lines in an experiment to see if scientists can predict major earth movements. Sensors are also used by government regulators to monitor whether companies are complying with air pollution.
The electronic camera is a particularly interesting piece of hardware because it foreshadows major change for the entire industry of photography. Instead of using traditional film, an electronic camera captures images in electronic form for immediate viewing on a television or computer display screen.
Electronic cameras are of two types: still video and digital.
Still-video cameras: still video cameras are like camcorders. However, they capture only a single video image at a time. Because the cameras are meant to display images only on a television screen, the picture resolution and color range are limited. An example of a still video camera is the RC-570 from canon.
Digital cameras: more interesting is the digital camera. A digital camera uses a light sensitive processor chip to capture photographic images in digital form.
Here I describe four types:
- Audio input devices
- Video input devices
- Sensors
- Electronic cameras
Audio input Devices
Voice recognition devices are only one kind of audio input, which can include music and other sounds. An audio input device records of plays analog sounds and translates it for digital storage and processing. An analog sound signal represents a continuously variable wave within a certain frequency range. Such continuous fluctuations are usually represented with an analog device such as a cassette player. For the computer to process them, these variable waves must be converted to digital 0s and 1s, the language of the computer.
There are two ways in which audio is digitized:Audio board: analog sound from, say, a cassette player goes through a special circuit board called an audio board. An audio board is an add-on circuit board in a computer that converts analog sound to digital sound and stores it for further processing.
MIDI board: a MIDI board- MIDI stands for Musical Instrument Digital interface- is an add-on board that creates digital music. That is, the music is created in digital form as the musician performs, for example, on a special MIDI keyboards. The principal use of audio input devices such as these is to provide digital input for multimedia PCs. A multimedia system is a microcomputer that incorporates text, graphics, sound video, and animation is a single digital presentation.
Video input Devices
As with sound, most film and videotape is in analog form, with the signal a continuously variable wave. Thus, to be used by a computer, the signals that come from a VCR or a camcorder must be converted to digital form through a special video card installed in the computer. Two types of video cards are the frame grabber video and the full motion video: Frame grabber video card: some video cards, called frame grabbers, can capture and digitize only a single frame at a time. Full motion video card: other video cards: other video cards, called full motion video cards, can convert analog to digital signals at the rate of 30 frames per second, giving the effect of a continuously flowing motion picture. The main limitation in capturing full video is not input but storage. It takes a huge amount space to store just 1 second of video.
Sensors
A sensor is a type of input device that collects specific kinds of data directly from the environment and transmits it to a computer. Although you are unlikely to see such input devices connected to a PC in an office, they exist all around us, often in invisible form. Sensors can be used for detecting all kinds of thing: speed, movement, weight, pressure, temperature, humidity, wind, and current, fog, gas, smoke, light, shapes, images, and so on.
Beneath the pavement, for example, are sensors that detect the speed and volume of traffic. These sensors send data to computers that can adjust traffic lights cars and trucks away from gridlocked areas. In aviation, sensors are used to detect ice buildup on airplane wings or to alert pilots to sudden changes in wind direction. In California, sensors have been planted along major earthquake fault lines in an experiment to see if scientists can predict major earth movements. Sensors are also used by government regulators to monitor whether companies are complying with air pollution.Electronic Cameras
The electronic camera is a particularly interesting piece of hardware because it foreshadows major change for the entire industry of photography. Instead of using traditional film, an electronic camera captures images in electronic form for immediate viewing on a television or computer display screen.
Electronic cameras are of two types: still video and digital.
Still-video cameras: still video cameras are like camcorders. However, they capture only a single video image at a time. Because the cameras are meant to display images only on a television screen, the picture resolution and color range are limited. An example of a still video camera is the RC-570 from canon.
Digital cameras: more interesting is the digital camera. A digital camera uses a light sensitive processor chip to capture photographic images in digital form.
Comments
Post a Comment