- Supporting software
The functions of the scanner should be realized by corresponding software. Except for the driver and scanning operation interface, almost every scanner will give away some image editing software, OCR text recognition software and others at random. Different scanning software varies in performance and operation method. For users who are not familiar with graphic processing, it is recommended to choose a scanner with simple operation and convenient use.
- Interface
Interface refers to the connection mode between scanner and computer. Common interfaces include SCSI interface, EPP interface and USB interface.
SCSI interface scanner is connected to computer through SCSI interface card, and data transmission speed is fast. The disadvantage is that the installation is complicated, requiring an expansion slot and limited computer resources (interrupt number and address). If you scan a large number of drawing files frequently, you should choose SISC interface scanner, which can save a lot of time.
The EPP interface (printer parallel port), easy to install, can be connected to scanner, printer and computer by cable. It can connect notebook computer. However, its data transmission speed is slightly slower than SCSI interface scanner. For users with low requirement for scanning speed, small scanning volume and infrequent use of scanner, it is recommended to purchase EPP interface scanner.
USB interface scanner is fast and supports plug and play. It is very convenient to connect with your computer, but it requires your computer support USB interface. If it is affordable for you, this one is recommended.
The working principle of scanner is as follows: Every kind of object in nature will absorb specific light waves, and the light waves that have not been absorbed will be reflected. The scanner uses the above principle to read the manuscript. When the scanner works, the strong light shines on the manuscript, and the unabsorbed light will be reflected to the optical sensor. After receiving these signals, the light sensor transmits these signals to an analog-to-digital (A/D) converter, which converts them into signals that can be read by a computer, and then converts them into correct images that can be seen on a display through a driver program. Manuscripts to be scanned can usually be divided into reflection and transmission. The former refers to general opaque documents such as newspapers and magazines, while the latter includes slides (positive) or exposures (negative). If it is often necessary to scan transmitted documents, a best document scanner with a mask (light plate) function must be selected.
