Scanning of the barcode requires a scanner that uses its own light source to illuminate the barcode, and then uses the photoelectric converter to receive the reflected light, converting the light and dark of the reflected light into a digital signal. No matter what kind of rule is printed, the barcode consists of a quiet zone, a start character, a data character and a terminating character. Some barcodes also have check characters between data characters and termination characters.
quiet zone: As the name implies, the area that does not carry any information plays a role.
start character: the first character, with a special structure, when the scanner reads the character, it begins to officially read the code.
data characters: the main content of the barcode.
check character: Verify that the data read is correct. Different encoding rules may have different verification rules.
Terminating character: The last character has the same special structure, which is used to inform the code to complete the scanning, and also plays the role of only the check calculation.
In order to facilitate two-way scanning, the start and stop characters have an asymmetrical structure. Therefore, the barcode information can be automatically rearranged when the scanner scans. Barcode scanner has three kinds of light pen, CCD and laser
Light pen: The most original scanning method, you need to manually move the light pen and also contact the barcode.
CCD: CCD is used as the photoelectric converter, and LED is used as the scanner of the illuminating light source. Within a certain range, automatic scanning can be achieved. And you can read a variety of materials, bar code on the uneven surface, and the cost is relatively low. However, the scanning distance is shorter than that of the laser type.
Laser: A scanner that uses a laser as a light source. Can be divided into line type, full angle and so on.
Line type: mostly used for handheld scanners, with a wide range and high accuracy.
Full angle: mostly horizontal, high degree of automation, automatic reading of barcodes in all directions.
The advantages of Barcode Technology:
Barcode is by far the most economical and practical automatic identification technology. Bar code technology has the following advantages
A. Fast input speed: Barcode input is 5 times faster than keyboard input and enables “instant data entry”.
B. High reliability: keyboard input data error rate is one-three percent, using optical character recognition technology error rate is one in ten thousand, and bar code technology error rate is less than one millionth.
C. The amount of information collected is large: the traditional one-dimensional barcode can be used to collect information of dozens of characters at a time, and the two-dimensional barcode can carry thousands of characters of information, and has certain automatic error correction capability.
D. Flexible and practical: Barcode identification can be used as a means of identification alone, or it can be combined with related identification equipment to realize automatic identification, and can be connected with other control equipment for automatic management.
In addition, barcode labels are easy to manufacture, there are no special requirements for equipment and materials, identification equipment is easy to operate, no special training is required, and equipment is relatively inexpensive.