How to buy large-area engineering scanners?

The following points for the purchase of scanners is essential, I hope to give you in the purchase of large-area engineering scanners as a reference:

1. Key Technology (Technologies)

The imaging System (Imaging system) is the core of a large-area scanner, including image Acquisition (acquisition) and lighting system (illumination). According to the different color patterns of the image, the current large format scanner in the market mainly uses CIS (contact image sensor) and CCD (Optical coupling components) two technologies.

CIS technology scanners low-cost, small size, sharp image sharpness, but because the sensor color space (color spaces) relatively small, so scanning color image is not very full. CIS technology scanners are mainly suitable for technical documents (technical documents) such as CAD drawings, sketches, GIS maps, aerial pictures, clothing drawings, newspapers, Office documents, such as scanning, if you have only black and white documents need to be digitized, then it is recommended that you buy a black-and-white scanner. If you still have some color lines or color images but the color requirements are not high, then select the CIS color scanner is enough.

The CCD scanner is expensive, bulky, has a wider gamut of color gamut, scans for color image continuity, and is softer and fuller for shadows and high light details. CCD scanner has the widest applicability and can scan various types of documents well. But because the price is relatively expensive, especially suitable for the image accuracy of the user, for art image class document scanning, such as GIS map, aerial map, art works, photos, posters, sketches, etc.

2. Paper Feed organization (Paper feed)

The digitization of large-face documents requires that the document be driven through the scanner feed mechanism to complete digitization through the scanner imaging system, so be sure to test the paper adaptability of the scanner according to the type of document in the Unit (Paper Adaptive), for example, some scanners are not suitable for scanning thin newspaper documents, Because of its paper feed mechanism design problems, often paper jam or even damage the manuscript. And for example, some scanners are not suitable for scanning curly folds of the document, often paper jam or due to the problem of the paper into the scan resulting in the image crease can not remove the shadow, the effect is very poor. At present, the use of single roll paper transmission system (ASRPT) or all-wheel-drive dynamic paper transmission system (APT) large-face scanners, with dual LED lighting system, can be a good solution to the problem of paper jam and crease shadow, and can better improve the accuracy of scanned images.

Therefore, before buying a large-area scanner, it is best to put a variety of typical units of the unit (preferably useless, the paper is damaged or not afraid) to provide a prototype demonstration of the dealer to personally carry out the test and experience. For a thinner or folded-curled document, scan as many times as possible to see if the paper is jammed and how the image works in creases. Feed mechanism for the scanner's image accuracy is the most important, if you require higher image accuracy, such as GIS users, the proposal must be to the scene by the actual professional testing, manufacturers propaganda precision indicators often have a certain moisture in the inside.

3, the correct understanding of the main technical indicators (specifications)

Do not be confused by the technical specifications of the factory trademark, only the correct understanding of the real meaning in order to better choose their own large-face scanner

(1) Optical resolution (optical rselution)-scanner resolution does not look at the highest or interpolation resolution (interpolated resolution), to see the physical optical resolution.

For technical-class document scans, suitable for the choice of CIS scanner, the general optical 600dpi resolution is enough to meet the application, and no meaning, most of these scans will use the following 600dpi resolution scanning, the higher the resolution used, the file storage size will be increased in the form of geometric index.

For art image class document, this kind of application 600dip is slightly insufficient, can choose the current market mainstream optical 1200dpi CCD technology scanner, also enough to meet the application.

(2) Scanning speed (scanning Speed)

Manufacturers generally describe the speed of scanners in inches/sec, if you are on-site to test or watch the dealer's demo or exchange activities, be sure to figure out how much resolution the speed of the case, there is no software acceleration, because the software acceleration mode will often lose image quality.

Because ultimately you are aiming for the ultimate goal of satisfying electronic imagery, so in fact for the scanning speed should also consider more factors, including the scanner preheating time, document loading mode is flexible, scanning process can automatically complete such as rotation, cut image, to the manic point, whether need to scan to determine the scanning parameters, Scanning software can be scanned and then processed image functions, and so on, these factors will greatly affect the overall scanning time, the final scan of the document time will often be higher than the factory claimed time, which is the ideal time, is not in line with the actual scanning situation. High-efficiency large format scanner should be the boot, no preheating; The document is flexible to load, can be loaded from the side, can also be loaded from the middle, the scanning process can be completed once set up the operation without post-processing; for drawing blue can be used intelligent Adaptive mode of elimination of Blue (iat,intelligent Adaptive thresholding), just a scan, the later arbitrary adjustment of the elimination of blue parameters to achieve satisfactory results, no need to adjust the parameters to scan, multiple scan not only loss of manuscript, but also greatly reduce the efficiency, this is particularly important, need special attention.

(3) lighting system (illumination)

The main market for large-scale scanners are 16-bit grayscale or 48-bit true color image capture. For large-area scanners, the lighting system affects the quality of the scanned image, just like the eyes of the person, if the surrounding light is not good enough to see the scene is not clear. The scanner on the market uses the cathode cold light source or the LED (light-emitting diode) light source illumination system, because the LED light source does not need preheat to turn on namely uses the characteristic already widely for the big-face scanner uses. At present, the use of symmetrical dual LED (bi-directional LEDs) light source lighting system designed large-face scanner has been considered to be able to effectively eliminate the shadow, and bring better image quality, especially with single roller transmission mechanism, The details of the crease can be reduced better when dealing with a folded document with creases.

(4) interface (Interface)

The current mainstream large-area scanner's interface has been upgraded to a more convenient and fast USB2.0 interface, such interface Plug and Play, the use of extremely convenient. With the application of the network more and more widely, mainstream manufacturers have introduced USB and Gigabit Ethernet dual interface. Gigabit Ethernet interface can overcome the USB interface limited by distance (generally up to 2 meters), theoretically speaking length can be unrestricted, provides a higher than the USB interface data transmission speed, can be installed from the network arbitrary scan driver software on the computer to scan.