Chinese name: two-dimensional code
Extrinsic name: 2-dimensional bar code
Role: record information
Applications: commercial activities, network links
Alias: two-dimensional bar code
Common types: stacked barcode
Common type: stacked barcode
Common types: stacked two-dimensional code, matrix two-dimensional code
Dimensional barcode/two-dimensional barcode (dimensional barcode) is a specific geometric pattern according to certain laws in the plane (two-dimensional direction) distribution of black and white graphic record data symbols of the information; code compilation on the clever use of the internal logic of the computer constituting the basis of the It has some ** of barcode technology: each code system has its specific character set; each character occupies a certain width; has a certain check function, etc. It also has the ability to check the information of different lines. At the same time, it also has the function of automatic identification of different lines of information, and processing of graphic rotation changes and other characteristics. In many kinds of two-dimensional bar code, commonly used code system: Data Matrix, Maxi Code, Aztec, QR Code, Vericode, PDF417, Ultracode, Code 49, Code 16K, etc., QR code was invented by the Japanese Denso-Wave company in 1994. QR comes from the English "Quick Response" abbreviation. QR code comes from the abbreviation of English "Quick Response", that is, the meaning of quick response, from the inventor hopes that the QR code can make its content quickly be decoded. QR code is most commonly used in Japan, Korea; and is currently the most popular two-dimensional space barcode in Japan.
Categorization
Two-dimensional barcodes/QR codes can be categorized into stacked/rowed 2D barcodes and matrix 2D barcodes. It has some ****ness of barcode technology: each code system has its specific character set; each character occupies a certain width; has a certain check function, etc.. At the same time, it also has the function of automatic identification of different rows of information, and the handling of graphic rotation changes and other characteristics. Stacked / rows of 2D barcode form is stacked by a number of rows of truncated 1D barcode; matrix 2D barcode in the form of a matrix composition, in the corresponding element of the matrix position with the "point" represents the binary "1", with the "empty" represents the "1", with the "empty" represents the "1", with the "1", with the "1", with the "1", with the "1", with the "1" and the "1". In the corresponding element position of the matrix, "point" means binary "1", and "empty" means binary "0", "point" and "empty" are arranged to form a code.
Stacked/rowed
Stacked/rowed 2D barcodes are also known as stacked 2D barcodes or layer-rowed 2D barcodes), and their encoding Common 2D barcodes
Principle is to be built on top of the 1D barcodes, and stacked into two or more rows according to the need. It inherits some characteristics of 1D barcode in terms of code design, checking principle, reading method, etc. The reading equipment and barcode printing are compatible with 1D barcode technology. However, due to the increase in the number of rows, it is necessary to determine the rows, and its decoding algorithm and software are not exactly the same as that of 1D barcode. Representative rows of 2D barcodes are: Code 16K, Code 49, PDF417 and so on.
Matrix two-dimensional code
Matrix two-dimensional barcode (also known as checkerboard two-dimensional barcode) it is in a rectangular space through the black and white pixels in the matrix of different distribution of the code. In the corresponding element position of the matrix, the appearance of the point (square point, round point or other shapes) indicates the binary "1", the point does not appear to indicate the binary "0", the point of the arrangement of the combination of the matrix to determine the meaning of the two-dimensional bar code represents. Matrix two-dimensional bar code is built on the basis of computer image processing technology, the principle of combinatorial coding, a new type of graphic symbols automatically read and process the code system. The representative matrix two-dimensional bar code has: Code One, Maxi Code, QR Code, Data Matrix and so on. In the dozens of two-dimensional bar code, commonly used code system: PDF417 two-dimensional bar code, Datamatrix two-dimensional bar code, Maxicode two-dimensional bar code, QR Code, Code 49, Code 16K, Code one, etc. In addition to these common two-dimensional bar code, there are also Vericode bar code, CP bar code, Codablock F barcode, Field code, Ultracode barcode, Aztec barcode.
The difference between two-dimensional code and one-dimensional code
Multi-line barcode, which does not need to be connected to a database, can store a large amount of data itself, used in: hospitals, driver's licenses, material management, transportation of goods, and when the barcode is subjected to a certain amount of damage, the error correction enables the barcode to correctly decode the two-dimensional code. It is a multi-line, continuous, variable-length symbolic identifier that contains a large amount of data. Each barcode has 3 - 90 lines, each line has a start section, a data section, and an end section. Its character set includes all 128 characters and the maximum data content is 1850 characters. A 1D barcode expresses information only in one direction (usually horizontal), while it does not express any information in the vertical direction, and its certain height is usually to facilitate the alignment of the reader. The application of one-dimensional bar code can improve the speed of information entry and reduce the error rate, but one-dimensional bar code also has some shortcomings: data capacity is small: about 30 characters can only contain letters and numbers, the bar code size is relatively large (low space utilization), the bar code can not be read after damage The bar code that stores information in the two-dimensional space of the horizontal and vertical direction is called two-dimensional bar code. A bar code that stores information in two dimensions, horizontally and vertically, is called a dimensional bar code.)
Two-dimensional bar code PDF417
PDF417 code is invented by Dr. Yinjing Wang, a Chinese American, PDF is the abbreviation of the first letter of the three words of English Portable Data File, which means "portable data file". Because the composition of the bar code of each symbol character is composed of four bars and four empty composition, if the composition of the bar code of the narrowest bar or empty called a module, the four bars and four empty of the total number of modules must be 17, so called 417 code or PDF417 code. 1. Large information capacity PDF417 code in addition to letters, numbers, ASCII characters, but also can express binary numbers. In order to make the code more compact, improve the information density, PDF417 in the encoding of three formats: extended alphanumeric compression format can accommodate 1850 characters; binary / ASCII format can accommodate 1108 bytes; digital compression format can accommodate 2710 numbers. 2. Error Correction Capability One-dimensional barcodes usually have checksums to prevent misreading and will be rejected if the barcode is defaced. The two-dimensional bar code not only prevents errors, but also corrects errors, even if the bar code is partially damaged, but also the correct information can be restored. 3. 3. Printing requirements are not high Ordinary printing equipment can be printed, faxes can also be read. 4. can be read by a variety of reading devices PDF417 code can be used with a laser reader raster, linear and surface scanning image reader. 5. Adjustable size to adapt to different print space 6. Code open has formed an international standard, China has also developed a 417-code national standards.
Error Correction Function
The error correction function of 2D barcode is realized by repeating part of the information (redundancy). For example, in the PDF417 code, a certain line contains, in addition to the information in this line, some information reflecting characters in other positions (error correction code). In this way, even when a part of the bar code is damaged, but also through the existence of other positions in the error correction code to restore its information. The error correction capability of PDF417 is divided into 0~8***9 levels depending on the number of characters in the error correction code. The higher the level, the more characters in the correction code, the stronger the correction capability, and the larger the barcode. When the correction level is 8, the barcode can be read correctly even if it is 50% defaced.
Deformation
PDF417 also has several deformed code forms: PDF417 truncated code In a relatively "clean" environment, where there is little chance of bar code damage, the right line indicator can be omitted and the terminator can be reduced. PDF417 Microcode A further reduction of the PDF code. Macro PDF417 Code When the content of a document is too long to be represented by a single PDF417 code, it can be represented by a macro PDF417 code containing multiple (1~99999) barcode chunks.
Advantages
From the above introduction it can be seen that, compared with the one-dimensional bar code two-dimensional bar code has obvious advantages, summarized in the following aspects: (a) greater data capacity (b) beyond the limits of the alphanumeric (c) the relative size of the bar code is small (d) resistance to destruction
Advantages
1. High-density encoding, large information capacity : Can accommodate up to 1850 uppercase letters or 2710 numbers or 1108 bytes, or more than 500 Chinese characters, than the ordinary bar code information capacity of about dozens of times higher. 2. Wide range of encoding: the barcode can encode the information that can be digitized such as picture, sound, text, signature, fingerprints, etc., and express it with barcode; it can express many kinds of language text; it can express image data. 3. Strong fault tolerance, error correction function: this makes the two-dimensional bar code due to perforation, dirt and other causes of local damage, as always, can be read correctly, the damage area of up to 50% can still be restored to the information. 4. high reliability of decoding: it is lower than the ordinary bar code decoding error rate of two millionths of a million, the BER is not more than one ten millionth. 5. Encryption measures can be introduced: confidentiality, good security. 6. Low cost, easy to produce, durable.
Edit the characteristics of the two-dimensional code
1. High-density coding, information capacity: can accommodate up to 1850 capital letters or 2710 numbers or 1108 bytes, or more than 500 Chinese characters, than the ordinary bar code information capacity is about dozens of times higher. QR code format "Farewell to Kangqiao"
2. Wide range of encoding: the barcode can encode the information that can be digitized, such as pictures, sounds, text, signatures, fingerprints, etc., and express them in barcode; it can express a variety of languages and characters; and it can express image data. 3. Strong fault tolerance, error correction function: this makes the two-dimensional bar code due to perforation, dirt and other causes of local damage, as always, can be read correctly, the damage area of up to 50% can still be restored to the information. 4. High reliability of decoding: it is much lower than the ordinary bar code decoding error rate of two millionths, the error rate is not more than one ten millionth. 5. Encryption measures can be introduced: confidentiality, good security. 6. Low cost, easy to produce, durable. 7. Barcode symbol shape, size and scale variable. 8.2D barcode can be read by laser or CCD reader.
Color
Often we see and most of the software generated by the two-dimensional code is black, but in fact the color of the two-dimensional code generation technology is not complicated, and much loved by young people, there are a number of websites began to provide colorful two-dimensional code online free generation services. Based on the error correction function of QR code, even if the QR code is partially covered or lost, the scanning device can still identify the complete information recorded, there are many "personalized QR code" generation tools, some personalized patterns and QR code synthesis, to get personalized and can be recognized by the scanning device QR code, this kind of The "personalized QR code" has also become popular.
Current application
The 2D barcode has the characteristics of large storage capacity, high confidentiality, high tracking, high loss resistance, large backup, and cheap cost, etc. These characteristics are especially suitable for forms, security and confidentiality, tracking, certificates, inventory count, and data backup.
Application of Forms
Transmission and exchange of official forms, business forms, import and export declarations, manifests, etc., reduces the need for manual re-entry of form information, avoids human error, and reduces labor costs
Security Application
Encryption and transmission of confidential information such as business intelligence, economic intelligence, political intelligence, military intelligence, and private intelligence.
Tracking Applications
Automatic tracking of official documents, automatic tracking of production line parts, automatic tracking of customer service, automatic tracking of mail order delivery, automatic tracking of maintenance records, automatic tracking of hazardous materials, automatic tracking of logistic supplies, automatic tracking of medical checkups, and automatic tracking of ecological research (animals, birds, etc.). It can also be used as a platform for ecological research (animal, bird, etc.).
License application
Passport, ID card, registration card, driver's license, membership card, identification card, chain store membership card, and other licenses are registered and automatically entered to achieve "read-on-demand" and "instant access" information management.
Inventory Application
Automatic inventory of goods and fixed assets in logistics centers, warehousing centers, and logistics centers to achieve the effect of "immediate inventory and decision-making".
Backup Application
If the information of document form is unwilling or unable to be stored in electronic media such as disk or CD-ROM for backup, 2D barcode can be used to store backup, which is easy to carry, not afraid of folding, and can be stored for a long time, and can be photocopied and faxed to make more backups.
Newspaper applications
The two-dimensional code as a connection between newspapers, cell phones and the network of emerging digital media, newspapers use two-dimensional code technology to create a "three-dimensional newspaper" since the user to read the newspaper through the use of various types of two-dimensional code software on the smartphone scanning the two-dimensional code on the newspaper, the newspaper immediately into a "three-dimensional", the newspaper immediately into a "three-dimensional", and the user can use the two-dimensional bar code to read the newspaper. The newspaper immediately becomes "three-dimensional", and at the same time, you can also easily read and view the extended content of the newspaper. Domestic newspapers currently applying QR code include Huaxi Metropolis Newspaper, Changjiang Daily, Chengdu Business Daily, etc. Network resources can be applied to download online resources, such as e-books, games, applications, etc.
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