The first is the resolution, which is the most important technical index of the scanner. It represents the ability of the scanner to express the details of the image, and also determines the fineness of the image recorded by the scanner.
The second is gray scale, which represents the brightness level range of the image. The more levels, the wider the brightness range of the scanner image and the richer the levels. The gray scale of most scanners is 256.
The third is the color number, which indicates the range of colors that can be produced by the color scanner. It is usually expressed by the number of data transitions representing the color of each pixel, that is, bits. The so-called bit is the smallest storage unit of a computer. The value of one bit is represented by 0 or 1. The more bits, the more complex the image information can be represented.
The fourth is the scanning speed. There are many ways to express scanning speed, because scanning speed is related to resolution, memory capacity, floppy disk access speed, display time and image size, and is usually expressed by scanning time at a specified resolution and image size.
The fifth is the scanning format, which indicates the size of the scanned artwork, such as A4. A3.A0 format.
Extended data:
Scanner assembly
1, SCSI signal line connecting scanner and computer, mostly using usb cable.
2. Controlling the working software of the scanner is the bridge between the scanner and the application program.
3. Image editing software, optical file recognition software and automatic recognition software for printed board graphics.
4, display color or gray image display.
5. Output equipment: black and white or color laser printer, thermal dye sublimation, graphic printer or other color printing equipment.
In addition to the above basic components, it can also be matched with the following additional equipment to make it have more functions.
1, the transmission adapter (TMA) is used to scan transparent film materials.
2. Automatic document feeder (ADF) automatically scans up to 500 pages of text continuously.
characteristic
Density range is a very important performance parameter of scanner. The density range, also called pixel depth, represents the range of light and dark tones that can be distinguished by the scanner. Generally, the density range of roller scanners is greater than 3.5, while that of flat scanners is generally between 2.4 and 3.5.
summary
Scanner is a high-tech product integrating optics, mechanics and electricity. It is an important tool for inputting various forms of image information into the computer, and it is the third generation computer input device after the keyboard and mouse.
Scanners are more powerful than keyboards and mice. From the most original pictures, photos and films to all kinds of files and materials, they can be input into the computer, and then the information in these image forms can be processed, managed, used, stored and output. With the help of optical character recognition software OCR(optical Character Recognize), scanned documents can be converted into computer text.
principle
The working principle of the scanner is this: every object in nature will absorb a specific light wave, and the unabsorbed light wave will be reflected. The scanner uses the above principle to read the manuscript.
When the scanner works, strong light shines on the manuscript, and the unabsorbed light will be reflected to the optical sensor. After receiving these signals, the optical sensor transmits them to the analog-to-digital (A/D) converter, which converts them into signals that can be read by the computer, and then converts them into correct images that can be seen on the display through the driver.
The original to be scanned can usually be divided into reflection original and transmission original. The former generally refers to general opaque documents, such as newspapers and magazines, while the latter includes slides (positive films) or negatives (negative films). If you often need to scan the transmission manuscript, you must choose a scanner with mask (light plate) function.
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