How Do I Choose the Best Portable Scanner?

A scanner is a device that uses photoelectric technology and digital processing technology to convert graphics or image information into digital signals in a scanning manner.

1.1 Available in

Scanners can be divided into three major types:

Density range is a very important performance parameter for scanners. Density range is also called pixel depth. It represents the range of bright and dark tones that can be distinguished by scanners. Generally, the density range of drum scanners is greater than 3.5, while flat scanners The density range is generally between 2.4 and 3.5.

Although the market for scanners is becoming increasingly quiet, it is still a necessary peripheral for many consumers. For many users who are facing purchase, how to choose a better scanner, what is the development trend of the scanner?

In addition to the scanner in the scanning system, the effective components of scanning are composed of the following components.

The SCSI signal cable that connects the scanner to the computer, usually uses a USB cable.

The software that controls the scanner. It is the bridge between the scanner and the application.

Image editing software, optical file recognition software and printed board graphics automatic recognition software.

A monitor that displays color or gray images.

Output device: black and white or color laser printer,

The scanner is a fully competitive industry regulated by the market. After years of development, the entire industry brand has presented a situation of "a hundred flowers blooming". According to the data from the above research and investigation by Canon, Canon scanners still maintain the top brand awareness. This has nothing to do with its many years of brand management and excellent product quality. The "second camp" generally has a low level of attention, remaining below 10%, and the market competition is very fierce.

Scanners under 800 yuan accounted for 29.2% of the total product attention, indicating that the market demand for low-end products in the scanner industry is still strong. The price of mid-range and above products has weakened, and users have paid more attention to product functions, quality, and services. In the future, high-end scanner products of enterprises can expect better market performance.

The scanner can input graphics files such as pictures, documents, photos, films, drawings, etc. into the computer, and cooperate with printers and modems to have copying and faxing functions. Since the popular scanner has fallen below 1,000 yuan, the scanner has gradually become an office Engineering design, art design and computer equipment indispensable for home users. What kind of performance, what grade and what brand of scanner do you need?

I. Brand

Performance parameters

There are many descriptions of the scanner's performance parameters. The following introduces the technical indicators that general users need to consider when purchasing.

1. Scanning format: Scanning format usually has A4, A4 lengthened, A3, A1, A0 and other specifications. Large format scanners are expensive, and general home and office users recommend using A4 format scanners. Office users can also consider purchasing A3 format or even larger format scanners as needed.

2. Resolution: The resolution reflects the clarity of the scanned image. The higher the resolution, the sharper the scanned image. The resolution of the scanner is expressed in DPI (DotPerInch) in dots per inch. General office users recommend to choose a scanner with a resolution of 600 × 1200 (horizontal resolution × vertical resolution). The horizontal resolution is determined by the true resolution of the scanner optical system, and the vertical resolution is determined by the precision of the scanner drive mechanism. The horizontal resolution is mainly considered when purchasing.

3. Color digits: The color digits reflect the ability to distinguish the colors of the scanned image. Scanners with higher color digits will scan the image more colorfully. The number of color digits is expressed in binary digits. For example, for a 1-bit image, each pixel can carry 1-bit binary information and can only produce black or white colors. An 8-bit image can give 8-bit binary information to each pixel point and can produce 256 colors. Common scanner color digits are 24, 30, 36 and 42. It is recommended to purchase a scanner with 30-bit color or 36-bit color. The 30-bit scanner has become obsolete and is not recommended for purchase.

4. Photosensitive element: The photosensitive element is the eye of the scanner. The scanning quality is closely related to the use of the photosensitive element in the scanner. Useful photosensitive elements for common scanners are CCD (ChargeCoupledDevice) and CIS (ContactImageSensor). The scanner technology of CCD sensor is mature. It cooperates with an imaging system consisting of a light source, several mirrors and optical lenses to perform imaging on the surface of the sensor. It has a certain depth of field and can scan uneven objects. CIS is widely used in the photosensitive elements of facsimile machines. Its limit resolution is about 600 DPI, which is a certain gap compared with CCD technology. It is only used in low-end flatbed scanners.

Third, supporting software

The functions of the scanner must be realized by the corresponding software. Except for the driver and the scanning operation interface, almost every scanner will randomly give away some image editing software, OCR text recognition and other software. Different scans are provided with software performance, and the operation methods are different. For users who are not familiar with graphics processing, it is recommended to choose a matching scanner that provides simple operation and easy use.

Fourth, the interface

The interface refers to the connection between the scanner and the computer. Commonly there are SCSI interface, EPP interface and USB interface.

The SCSI interface scanner is connected to the computer through a SCSI interface card, and the data transmission speed is fast. The disadvantage is that the installation is more complicated and requires an expansion slot and limited computer resources (interrupt number and address). If you often scan a large number of images, you should choose a SISC interface scanner, which can save a lot of time.

The EPP interface (printer parallel port) can connect the scanner, printer and computer with a cable, which is easy to install. Can connect to laptop. However, its data transmission speed is slightly slower than the SCSI interface scanner. For users who do not require high scanning speed, small scan volume, and infrequently use the scanner, it is recommended to purchase an EPP interface scanner.

The USB interface scanner is fast and supports plug and play. It is very convenient to connect to a computer, but your computer is required to support the USB interface. Users with conditions are advised to purchase USB.

1. When the scanner switch is turned on, the scanner makes an unusual sound. This is because some scanner models have a lock, the purpose of which is to lock the lens group

, To prevent vibration during transportation, so the lock should be opened before turning on the scanner power switch.

2. Nothing happens when the scanner is powered on. Some types of scanners are energy-saving, and the lamp will only light up after entering the scanning interface.

It will go out automatically once you exit.

3 "Scanner not found" is displayed during scanning. This phenomenon may be caused by turning on the host first and then turning on the scanner.

Computer or refresh in the device management.

4 Is the resolution of the scanner and the resolution of the printer a concept? How should I choose a printer based on the resolution of the scanner? scanning

The unit of resolution of the instrument should be strictly defined as ppi, not dpi. ppi is the number of pixels per inch. For a scanner, each

Pixel is not a simple description relationship like 0 or 1, but a description of 24bit, 36bit or CMYK (1004). Printer resolution dpi

The d in the English refers to the dot in English. There is no difference between each dot, but the concept of 0 or 1. For a scanner, 1 pixel is required.

It is described by several dots (CMYK), that is, the color of a point is determined by the density of different dots. So the scanner's dpi and print

Machine dpi concept is different. Use a 1440dpi printer to output a 1: 1 image, and scan with about 100-150dpi.

5. The scanner displays the message "Not enough hard disk space or insufficient memory" while scanning. First, make sure the hard disk and memory are sufficient.

Large, please check if the scan resolution you set is too large and the file data is too large.

6. Scanning makes strange noise. Remove the cover of the machine, find some oil from the sewing machine on the toilet paper, wipe the dirt on the two tracks of the mirror group, and then

Sewing machine oil drops on the transmission gear set and the bearings at both ends of the belt (note that the amount of oil is moderate), and finally adjust the belt tension properly.

7. The scan takes too long. Check the remaining capacity of the hard disk, optimize the hard disk space, delete the useless TMP files first, do Scandisk, then do

Defrag or Speed Disk. Please note: If the final actual scanning resolution is set higher than the optical resolution of the scanner, the scanning speed

Degrees will slow down, this is normal.

1.Install USB scanner

The installation of this scanner is very simple, and users with almost no experience can quickly install a USB scanner in a short period of time. No matter what model or brand of scanner, the specific installation method is almost the same. Generally, the following steps are followed: (When installing a scanner, all brand installation steps are to install the scanner driver first. Connect the scanner to the USB interface of the computer using a USB data cable first. Then connect the scanner to the USB interface of the computer. Then check whether the scanner is connected to the computer. The CCD scanning element is fixed with a lock. If it is fixed, you should unlock the scanner and power on the scanner and the computer. Then the computer will automatically detect the USB scanner in the current system, and then follow the installation instructions on the screen to complete it. Installation of scanner driver and configuration software. After the installation is complete, you can use the editing software that comes with the scanner to bring up the application interface of the scanning software, and you can start using the scanner. In addition, when installing this type of scanner, you must also pay attention to the physical connection of the scanner, it is best to open the computer system connected to the scanner, enter the CMOS setting interface, open the BIOS system, make sure Open the Universal Serial Bus settings; at the same time, after the installation of the scanner, it is best to restart the computer to ensure that the various functions of the scanner are working properly.

2. Install ordinary scanner

The installation of this scanner is the most common situation for everyone. When installing this type of scanner, you should also connect the hardware first, and connect one end of the scanner cable to the port labeled "Port A" on the back of the scanner , Then connect the other end of the scanner cable to the LPT print port in the computer. After the hardware is connected, first power on the scanner and turn on the scanner. After the scanner is started for a few seconds, connect the computer to start the computer system, and then the computer will detect that the scanner has been connected to the system. ; Below you can install the scanner driver, put the scanner driver CD into the CD-ROM drive, the installation screen prompts to complete the driver installation. After the installation is complete, the driver will remind you to test the current connection of the scanner. If the scanner is installed successfully, a prompt screen will be displayed on the computer screen to tell you that the scanner installed in the system has been found. Just click the OK button in the prompt screen, and the installation of the scanner driver will be completed! Next, you can install the scanning application software that needs to be installed on your computer. After the scanning application software is installed and running, the first thing you need to do is to select the appropriate image source, and then select the just-installed from the required selection dialog box. The scanner is used as the image source of the application software, so that you can input images into the software through the scanner in the future.

3. Install a SCSI scanner

A SCSI scanner is also a typical type of scanner. The installation of the scanner is relatively more complicated than the installation of the previous two types of scanners. When installing a scanner using a SCSI interface, you first need to open the case of the computer connected to the scanner, select a free PCI slot in it, and then insert the SCSI interface card that comes with the scanner into the PCI slot. , Then use screws to fix the SCSI card in the computer's chassis; everyone uses the SCSI data cable that came with the scanner to connect the scanner to the interface on the SCSI card in the corresponding computer chassis; The computer is powered on sequentially. The Windows system in the computer will automatically detect the SCSI interface card installed in the system. Depending on the version of the Windows system, the computer will automatically identify the SCSI interface card and set the driver corresponding to the card. Program; if the system does not recognize the SCSI interface card, a device installation wizard dialog will open, and you can complete the installation of the scanner according to the instructions. If the system prompts a hardware conflict when installing the scanner SCSI interface card, especially when there are several SCSI devices connected to the same SCSI interface, you need to set the ID of each SCSI device. At the same time, the SCSI terminator should be set properly so that the scanner can be used correctly. Finally, everyone will follow the method described above to complete the installation of the scanner application software and other auxiliary software! ^[1]

An image file is a simple representation of hundreds, thousands, or even millions of pixels. A computer uses one or more bits.

The scanning process is quite simple. Put the material to be scanned on the scanner's glass surface, run the scanning software, and click the "Scan" button. The scanner will scan the image into the image editing software, and it can be saved in file format. Store. In order to get the best scanning results, you need to understand the factors that affect the quality of the scan.

Just like printers, the technology of scanners is also developing with each passing day, and it is becoming more and more user-friendly. Knowing the technical development of scanners and future development trends is very beneficial for us to buy machines. We will introduce the technical development of the scanner from the parameters that need attention when purchasing:

Optical resolution

Optical resolution is the most important factor when we choose a scanner. The scanner has two major resolutions, namely the maximum resolution and the optical resolution. It is directly related to the optical resolution that is usually used. The unit of the resolution of the scanner is strict. The definition should be ppi, but people also mistakenly call it dpi. ppi refers to the number of pixels per inch. Generally, horizontal resolution is used to determine the accuracy of the scanner, because the vertical resolution can be controlled by the stepper motor of the scanner, and the horizontal resolution is completely determined by the CCD accuracy of the scanner. At the beginning, the mainstream optical resolution was 300ppi, after 1999 it was about 600ppi, after 2000 it gradually transitioned to 1200ppi, and the mainstream optical resolution has reached 2400ppi. Therefore, as an ordinary user, we purchase a scanner with 2400ppi optical resolution is sufficient.

2. Scanning method

This is mainly for the photosensitive element, which is also called a scanning element, which is the part of the scanner that completes the photoelectric conversion. . In 1969, Bell Labs invented the CCD (Charge Coupled Device), which is small in size and low in cost, and is widely used in scanners.

CMOS was born in 1998, it is a new type of image sensing technology. The advantages of CMOS are simple structure and lower manufacturing cost than CCD.

Also in 1998, CIS was born. CIS scanners are smaller than CCD scanners and less expensive to manufacture, but they are still inferior in quality. The former focuses on the CCD through the lens, converts the optical signal into an electrical signal for imaging, and the latter touches the surface of the scanned document for contact scanning. Comparing the two scanning methods, you can see that the CIS as a contact scanning device has a smaller depth of field, and has a poor scanning effect on real objects and uneven originals. The CCD scanner focuses directly on the CCD through the lens, so its depth of field is greater than that of the CIS. The instrument is much larger and can be used for physical scanning. Generally, when we choose a scanner, we usually choose a CCD. And there are the most CCD scanners on the market.

3. Color digits

The number of color bits is an important technical indicator of the color gradation information that can be captured by the scanner. A high color bit can obtain a higher dynamic range, and the color performance is more beautiful. Color bit affects the color saturation and accuracy of the scanning effect. The color bit has developed rapidly, from 8 to 16 bits, to 24 bits, and from 24 to 36.48. This is directly related to the increasing requirements for the color reproduction of scanned objects. Therefore, the larger the color bit value, the better. However, 48-bit scanners are gradually moving towards the mainstream.

4.Interface type

The interface of the scanner refers to the connection between the scanner and the host computer. The development is from SCSI interface to EPP (abbreviated for Enhanced Parallel Port) interface technology. Nowadays, they have entered the USB era, and most of them are 2.0 interfaces. As an emerging industry standard, the USB interface has a better performance in terms of transmission speed, ease of use, and computer compatibility. Since its introduction in 1999, its share in the home market has continued to rise and has become a recognized standard. Although scanners with EPP interface can still be found on the market, almost all manufacturers have discontinued production.

5. Software configuration and other

Scanner configuration includes software image class, OCR class and vectorization software, etc. OCR is a relatively important software technology in the scanner market. It implements the function of converting printed text to scanned text and provides a brand-new The text input method greatly improves the user's work efficiency, and at the same time brings progress to the application of the scanner.

Also,. Shortcut keys have become a development trend. For home scanners, in addition to resolution, color level, and interface type, there are a series of auxiliary technical indicators to enhance the ease of use and other functions of the scanner. ^[3]