Input devices of computer images -best picks
In this article i will tell you some input devices of computer images. First of all you need to know what are input devices. Input device is a device through which data and instructions are entered into computer. An input devices converts the data and instructions into binary form or machine readable form for acceptance by the computer because computer can understand only binary language i.e. machine language. The most commonly used input device is a keyboard. Thats why it is very important to know the input devices of computers and now i will tell you Input devices of computer images.
Here are some of the commonly used input devices used are:-
2. Punched card
6. Light pen
8. Voice input device
11. Digital cameras
1. Input devices of computer images (keyboard)
Keyboard is an input device for entering data and instructions. A keyboard is similar to the keyboard of typewriter. It contains normally 101 keys. But nowadays more key keyboards are also available in the market. These keys can be divided into the following categories :-
- Alphabetic keys :- A to Z and a to z
- Numeric keys :- 0 to 9
- Function keys :- F1 to F12
- Special keys:- + – * / , ; () $ ? etc. So all other keys are special keys.
2. Input devices of computer images (punched card)
Few years back , punched cards were the most popular and widely used input medium for most computer systems. Nowadays a wide variety of fast input devices are available. But we have to understand the concept of the punched cards. There are two types of punched cards:-
1. 80-column card :- This card is divided into 80 vertical columns numbered 1 to 80 from left to right. It is again divided into 12 rows as 12,11,0,1,………….,9 from top to bottom. Each column can represent one character. So maximum 80 characters can be represented by a single card.
2. 96-column card :- The 96 -columns are separated into three 32 column sections. So its size is one third of 80 column card. The upper portion of card is used as print area and not used for punching holes. These cards have round holes instead of rectangular holes. The standard 6-bit BCD code is used for recording data. Each of the 96 columns has six punch positions. Upper two are zone positions and other four are numeric positions. The presence of a hole in a punch position indicates 1 bit.
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3. Input devices of computer images -best picks (mouse)
A mouse is also an input device which can also be called as pointing device because it is used to point and select some option on screen. It controls the movement of tge cursor on the display screen. It is held in one hand and moved across a flat surface. A mouse may have one,two or three buttons. Mouse is important for graphical user interface (GUI) because we can simply point to options and objects and click a button. Its direction can be controlled by a small ball inside the mouse. Sensors register the movement of the ball and send an electronic message to the computer about the position of the mouse.
4. Input devices of computer images (joystick)
It is also a pointing device commonly used with computer games. It consists of a lever which moves in all directions and controls the movement of pointer. As per its name it is handsized stick mounted on a base unit. The stick can be pulled and pushed in all directions. Joystick has a number of different buttons programmed to control different activities such as firing a weapon, shooting a ball etc. depending upon the game.
5. Input devices of computer images (Track ball)
Track ball is also a pointing device . It contains a ball which can rotate in any direction. The user spins the ball in different directions to move the cursor on the screen. The electronic circuitry detects the direction and speed of the spin and the information is sent to the processor. Trackball can be placed on any type of surface so, it is very popular device for portable computers.
6. Input devices of computer images (light pen)
A light pen is a pointing device which can be used to select a portion by just pointing on it. We can draw figures directly on the screen and move the figures around. It is photosensitive pen capable of sensing a position on screen when its tip touches the screen. When its tip is moved over the screen, its photocell sensing elements detects the light coming from the screen snd corresponding signals are sent to the processor.
7. Input devices of computer images ( voice input devices)
These devices are used to recognize the voice and translate it into the text using voice recognition systems. Most voice recognizer systems are speakers dependent i.e. they must be separately trained for each individual users. Therefore, a database of words must be created for each person using the system to recognize the language of each individual. So that words can be recognized correctly.
8. Input devices of computer images (Touchscreen)
It is also a pointing device by which users touch areas of the screen with their fingers to issue commabds. Touching one button may take the user to another series of buttons where they can choose their choices. A common application of touch screen is ATM’s installed in banks. We can operate our account by just touching the screen.
9. Input devices of computer images (Digitizer)
The digitizer device is used for converting two or three dimensional graphic input such as charts , graphs and blueprints into digital form that can be manipulated and stored by the computer. A digitizing system consists of a programmable controller and a flat pointing table adjusting for rack and elevation. The components used in conjunction with the graphics tablet may include a stylus or pen , a push button cursor and a menu. The tablet is available in wide ranges of size. To digitizers may be used in conjunction with cathode ray tubes.
10. Input devices of computer images (scanners)
Scanners are the input devices capable of entering information directly into the computer. The main advantage of direct entry of information is that users do not have to key in the information. The two major types of scanners are optical scanners and magnetic -ink character readers.
1. Optical scanners:- The optical scanners are capable of reading information recorded on paper, employing light source and light sensors. The information to be scanned is typewritten information, information cided as ink or pencil marks or information coded as bars.
The following are the commonly used optical scanners :-
- Optical character reader(OCR):- An OCR detects alphanumeric characters printed or typewritten on paper. It may be a hand held scanners or a page scanner to detect light reflected from a line or form a page of the text. The change in the reflected light is converted to binary data whuch is sent to the processor. The text which is to be scanned is illuminated by a low frequency light source. The light is absorbed by the dark areas while the light is reflected from the lighted source. An OCR can scan several thousands of printed or typewritten characters per second.
- Optical mark reader(OMR):- special marks such as square or bubble are prepared on examination answer sheets or questionnaires. The user fill in these squares or bubbles with soft pencil or ink to indicate their choice. These marks are detected by an OMR and the corresponding signals are sent to the processor. If a mark is present, it reduces the amount of reflected light. If a mark is not present, the amount of reflected light is not reduced. This change in the amount of reflected light is used to detect the presence of a mark.
- Optical bar code reader:- Thus methid uses a number of bars (lines) of varying thickness and spacing between them to indicate the desired i formation. Bar codes are used on most grocery items. An optical bar cide reader can read such bars and convert then into electrical pulses to be processed by a computer.
2. Magnetic ink character recognition(MICR):- MICR is widely used by banks to process large volumes od cheques and deposit forms written every day. A special ink called magnetic ink i.e. an ink which contai s iron oxide particles is used to write characters on the cheques and deposits forms which are to be processed by an MICR. MICR is capable of reading characters on a paper written with magnetic ink. The magnetic ink is magnetized during the input process. The MICR reads the magnetic pattern of the written characters. To identify the characters these patterns are compared with special pattern stored in memory.
11. Input devices of computer images (Digital cameras)
Digital cameras work much like PC video cameras, except that digital cameras are portable, handheld device that capture still images. Whereas normal film cameras capture images on a specially coated film. Digital cameras capture images electronically. The digital camera digitize the image, compresses it an stire it on a special disk or memory card. The user can then copy the information to a PC, where the image can be edited, copied, printed, embedded in a document to transmitted to another user. Most digital cameras can stire dozens of high resolution images at a time.
So this is all about the input devices of computer images -best picks. I hope this article was useful for you and if you have any questions related to this article feel free to ask me in the comment section below.
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