What is an Image Scanner?

An image scanner is a computer external device that captures an image and converts it into a digital input device that the computer can display, edit, store and output. It can extract and convert original lines, graphics, text, photos, and plane objects into digital forms that can be edited and added to files. In remote sensing applications, optical remote sensing images can be converted into digital remote sensing images and then input to a computer for processing.

Image scanner

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An image scanner is a computer external device that captures an image and converts it into a digital input device that the computer can display, edit, store, and output. It can extract and convert original lines, graphics, text, photos, and plane objects into digital forms that can be edited and added to files. In remote sensing applications, optical remote sensing images can be converted into digital remote sensing images and then input to a computer for processing.

Chinese name

Image scanner

Nature

Computer external equipment

For formal use

Display, edit, store thickness and output

Classification

Desktop and manual scanners

The principle of the scanner is actually very simple, just like we usually look in the mirror. When it scans the image (only one line at a time), the light is reflected back from the object and shot into the CCD (charge coupled device) through the lens. The CCD converts the light into an analog voltage signal, and marks the gray level of each pixel. Then the ADC (analog-to-digital converter) converts the analog voltage signal into a digital signal. Each color uses 8, 10, or 12 bits. Indicates that after scanning, it is saved in the computer in Twain (Special Format for Scanned Images) format.

Scanners fall into two major families: desktop scanners and manual scanners.

First let's talk about the desktop scanner. It is relatively large and heavy, so it is not easy to carry out. However, it is low in value and can scan high-resolution color pictures, so everyone likes it very much.

And its brother manual scanner, although it is lightweight, small, easy to carry, and cheap, but it can only scan low-resolution grayscale or black and white pictures, so it has been forgotten by everyone.

Going to the computer market, it is not difficult to find out more than a dozen brands of scanners. Among the variety of models, how do we choose? Can generally be considered from the following aspects:

Optical resolution DPI (that is, the number of scanning points per inch): In general, households must reach 600x300, and professional is preferably not less than 600x600;

Scanning digits: most of the market are 30 or 32 digits, and the best is 36 digits.

Scanner size: Normally the size of A4 paper.

Scanner interface: Parallel interface is more economical, but preferably SCSI interface.

Software provided: The supplied software or driver and manual are preferably in Chinese.

The most popular brands in the Chinese market are: Microteck, HP, UMAX, AGFA, etc. scanners, you can choose to buy according to your needs and economic conditions.

The installation of the scanner is very simple, just connect the two ends of the cable to the parallel port of the computer and the scanner, and then connect the power to the scanner. Then check if Windows 95 & 98 has detected new hardware and install the scanner Drivers and software.

Note: Be careful when installing the scanner! The scanner's light is very strong and harmful to people. Avoid looking at it as much as possible.

When using the scanner software, pre-scan the image first, then set the number of colors, DPI, contrast, brightness, etc., and finally select the area to scan and start scanning. When selecting DPI, generally choose 150-720, because the higher the DPI, the larger the file, and if you often use a high DPI M to scan the image, the life of the scanner will be shortened.