The scanner can input pictures, manuscripts, photos, films, drawings, and other graphic documents into the computer, and has the functions of copying and sending faxes if in cooperation with printers and modems. As the popular scanners have dropped to less than 1,000 yuan, the scanner has gradually become indispensable computer equipment for office users and home users, engineering design, and artistic design. How to choose the scanner's performance? The following is a detailed introduction for everyone:
The scanner has many performance parameters, and the following are the technical indexes that ordinary users need to consider when purchasing.
- Scanning format: The scanning format usually has A4, A4 Plus, A3, A1, A0, and other specifications. The price of a large format scanner is very high, and it is suggested that common family and office users select the A4 format scanner. According to the needs, office users can also consider A3 book scanner or even larger format scanner.
- Resolution: Resolution reflects the clarity of the scanned image. The higher the resolution of the scanner is, the clearer the scanned image is. The resolution of the scanner is expressed in dots per inch (dpi). General office users suggest purchasing a scanner with a resolution of 600×1200 (horizontal resolution × vertical resolution). The horizontal resolution is determined by the real resolution of the scanner's optical system, while the vertical resolution is determined by the precision of the scanner's transmission mechanism. When purchasing, the horizontal resolution is mainly considered.
- Color digits: Color digits reflect the ability to distinguish colors of scanned images. The higher the number of color bits is, the richer the color of the scanned image is. The number of color bits is expressed in binary digits. For example, for a 1-bit image, each pixel can carry 1-bit binary information, and only black or white can be generated. An 8-bit image can give each pixel 8 bits of binary information and can generate 256 colors. Common scanner color bits include 24 bits, 30 bits, 36 bits, and 42 bits. It is recommended to purchase a 30-bit color scanner or a 36-bit color scanner.
- Photosensitive elements: Photosensitive elements are the eyes of the scanner. The scanning quality is closely related to the photosensitive elements adopted by the scanner. CCD and CIS are useful photosensitive elements for common scanners. The scanner technology of CCD photosensitive element is mature. It is matched with an imaging system consisting of a light source, a plurality of reflecting mirrors, and an optical lens to the image on the surface of the sensor, has a certain depth of field, and can scan uneven objects. CIS is a photosensitive element widely used in fax machines. Its limit resolution is about 600DPI, which has a certain gap from CCD technology. CIS is only used in low-grade flat-panel scanners.