Just like printers, scanner technology is also developing with each passing day and is becoming more and more humane. It is very beneficial for us to have a clear understanding of scanner technology development and future development trends. There are many different scanners, such as high speed portable hd doc scanner, pdf camera scanner, and so on. We will introduce the technological development of the scanner from the parameters which need to be paid attention to when purchasing:
- Optical resolution
Optical resolution is the most important factor for us to choose and buy a scanner. Scanners have two major resolutions, namely, maximum resolution and optical resolution, which are directly related to the optical resolution normally used. The unit of scanner resolution is strictly defined as PPI, but it is also commonly called dpi by mistake. Ppi refers to the pixel number per inch. Transverse resolution is generally used to determine the accuracy of the scanner, because the longitudinal resolution can be controlled by the stepper motor of the scanner, while the transverse resolution is completely determined by the CCD accuracy of the scanner. In the beginning, the mainstream optical resolution was 300ppi, after 1999 it was about 600ppi and increased to 1200ppi after 2000, and the mainstream optical resolution has reached 2400ppi. Therefore, as ordinary users, we can buy 2400ppi optical resolution scanners.
- Scan mode
This is mainly for the photosensitive element, which is also called the scanning element. It is the part of a scanner that completes the photoelectric conversion. In 1969, Bell Laboratory invented CCD(Charge Coupled Device), which is widely used in scanners because of its small size and low cost.
CMOS was born in 1998. It is a new image sensing technology. CMOS has the advantages of simple structure and lower manufacturing cost than CCD.
Also in 1998, CIS was born. CIS scanner is smaller than CCD scanner and its manufacturing cost is lower, but its quality is still not as good as that of CCD scanner. The former focuses on the CCD through the lens to convert optical signals into electrical signals for imaging, while the latter carries out contact scanning close to the surface of the scanned manuscript. Comparing the two scanning methods, it can be seen that CIS, as a contact scanning device, has a smaller depth of field and a poorer scanning effect on physical objects and uneven originals. The CCD scanner is focused on the CCD through the lens and is directly sensitive to light, so its depth of field is much larger than that of the CIS scanner, and it is very convenient to scan objects. In general, when we buy scanners, we usually choose CCD. Moreover, CCD scanners are also the most sufficient in the market.
- Color digits
Color digits are an important technical index that the scanner can capture color level information. High color bits can obtain a higher dynamic range, and its color performance is more gorgeous and realistic. Color position affects the color saturation and accuracy of the scanning effect. The color bit has developed rapidly, from 8 to 16, then to 24, and then from 24 to 36.48. This is directly related to our increasing requirements for color restoration of scanned objects, so the larger the color bit value is, the better it is. However, 48-bit scanners are gradually moving into the mainstream.
- Interface type
The interface of the scanner refers to the connection mode between the scanner and the computer host. The development is from SCSI interface to EPP (abbreviated as Enhanced Parallel Port) interface technology, but now it has entered the USB era and is mostly 2.0 interface. As a new industry standard, the USB interface has performed well in terms of transmission speed, ease of use, and computer compatibility. Since it was introduced in 1999, its share in the home market has been rising steadily and has become a recognized standard.
- Software configuration and others
Scanner configuration includes software image, OCR and vectorization software, etc. OCR is a relatively important software technology in the scanner market. It realizes the function of converting images scanned from printed text into literal text, provides a brand-new text input method, greatly improves the working efficiency of users, and also brings progress to scanner application.
In addition, shortcut keys have become the trend of development. For home scanners, there are a series of other auxiliary technical indicators besides resolution, color bit, and interface type to enhance the usability and other functions of the scanner.