What kind of device does the scanner belong to among external devices?

Among external devices, scanners belong to "input devices". An input device is a device that inputs data and information into a computer; a scanner can convert images into a digital format that can be displayed, edited, stored and output by the computer. It is a powerful image input device.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Among external devices, scanners belong to "input devices".

Input device: A device that inputs data and information to the computer. It is a bridge between computers and users or other devices. Input device is one of the main devices for information exchange between users and computer systems

Input device (InputDevice) is a device for humans or external devices to interact with computers. It is used to convert raw data and process these data. program into the computer. Computers can receive a variety of data, which can be numerical data or various non-numeric data, such as graphics, images, sounds, etc., which can be input into the computer through different types of input devices for processing. Storage, processing and output.

Computer input devices can be divided into the following categories according to their functions:

• Character input devices: keyboard;

• Optical reading equipment: optical mark reader, optical character reader;

• Graphic input equipment: mouse, joystick, light pen;

• Image input devices: cameras, scanners, fax machines;

• Analog input devices: Language analog-to-digital conversion recognition system

A scanner is a device for capturing images. As an optical, mechanical and electrical integration computer peripheral product, the scanner is the third largest computer input device after the mouse and keyboard.It can convert images into a digital format that can be displayed, edited, stored and output by a computer. It is a powerful input device.

Extended knowledge: scanner performance indicators

The performance indicators of the scanner mainly include resolution, gray level and number of colors. In addition, there are Scanning speed, scanning format, etc.

• Resolution

  Resolution represents the scanner's ability to express image details, usually expressed by the number of pixels contained in the scanned image per inch of length. , that is, Dot Per Inch.

• Grayscale

  Grayscale represents the brightness level range of a grayscale image. The more levels, the wider the scanner image brightness range and the richer the layers.

• Color number

  The color number indicates the range of colors that the color scanner can produce. It is usually represented by the data leap number that represents the color of each pixel, that is, bits. For example, 36bit means that there are 2^36 colors on each pixel.

• Scanning speed

  Scanning speed is usually expressed by the scanning time under a certain resolution and image size.

• Scanning format

  indicates the size of the scanned artwork, the common ones are A4 format, others include A3, A0 format, etc.

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