Bar code encoding method:
There are many kinds of bar codes, and there are about twenty common coding systems, including:
Code39 (standard code 39), Codabar code (Kudebar code), Code25 (standard code 25), ITF25 code (cross code 25), Matrix25 code (matrix code 25), UPC-A code, UPC-E code, EAN- 13 code (ean-/. China postal code (a variant of matrix 25 code), Code-B code, MSI code, Code 1 1 code, Code93 code, ISBN code, ISSN code, Code 128 code (Code 128 code, including ean/.
At present, there are EAN and UPC codes widely used in the world, which are used to uniquely identify a commodity in the world. This is the most common bar code in supermarkets), Code39 (which can represent numbers and letters, and is widely used in management field), ITF25 (which is widely used in logistics management), Codebar (which is mostly used in medical and book fields), Code93, Code 128 and so on. Among them, EAN code is a commodity bar code widely used in the world today, which has become the basis of electronic data interchange (EDI). UPC code is mainly used in the United States and Canada; In all kinds of bar code application systems, Code39 is widely used in the internal management of various industries because it can be composed of numbers and letters * * *. Codebar code is also widely used in the business of blood bank, library and photo studio.
In addition to the one-dimensional bar codes listed above, two-dimensional bar codes have also developed rapidly and found applications in many fields.
Introduction to common bar codes:
EAN code:
EAN code is a kind of commodity bar code formulated by ean international, which is used all over the world. There are two kinds of EAN code symbols: standard version (EAN- 13) and shortened version (EAN-8), and the common commodity bar code in China is equivalent to it. The bar code printed on the packaging of the goods we buy every day is generally EAN code.
UPC code:
UPC code is a commodity bar code formulated by the Uniform Code Committee of the United States, which is mainly used in the United States and Canada, and we can see it on the goods imported from the United States.
Size 39:
Code 39 is a kind of bar code that can represent numbers, letters and other information. It is mainly used for the automatic management of industry, books and tickets, and is widely used at present.
Codebar code:
Kudba code can also represent numeric and alphabetic information, which is mainly used for automatic identification in medical and health care, library and information, materials and other fields.
Two-dimensional barcode:
One-dimensional bar codes carry limited information. For example, bar codes on commodities can only hold 13 Arabic numerals (EAN- 13 codes), and more information can only be supported by commodity databases. Without the pre-established databases, such bar codes are meaningless, thus limiting the application scope of bar codes to some extent. For this reason, the two-dimensional bar code was invented in the 1990s. In addition to the advantages of one-dimensional bar code, two-dimensional bar code also has the advantages of large amount of information, high reliability, confidentiality and strong anti-counterfeiting.
At present, two-dimensional bar codes mainly include PDF4 17 code, Code49 code, Code 16K code, Data Matrix code, MaxiCode code code, etc., which are mainly divided into two categories: stacked or layered code and chessboard or matrix code.
As a new information storage and transmission technology, two-dimensional bar code has been widely concerned by the international community since its birth. After several years of efforts, it has been applied in many fields, such as national defense, public security, transportation, medical care, industry, commerce, finance, customs and government management.
With its huge information carrying capacity, two-dimensional bar code can include the information stored in the background database when using one-dimensional bar code in the past, and the corresponding information can be obtained directly by reading the bar code. Moreover, two-dimensional bar code also has error correction technology and anti-counterfeiting function, which increases the security of data.
Two-dimensional bar code can be used to compile photos and fingerprints, which can effectively solve the problems of machine-readable and anti-counterfeiting documents. Therefore, it can be widely used in passports, identity cards, driving licenses, military certificates, health certificates, insurance cards and so on.
The technology of PDF4 17 has been adopted in driver's license, American military card and military medical card in more than ten states, including Arizona, USA, several years ago. The personal information and photos on the certificate are encoded in the two-dimensional bar code, which not only can realize the automatic reading of the ID card, but also can effectively prevent the occurrence of counterfeit documents. Many countries, such as the Philippines, Egypt, Bahrain, etc., have also adopted two-dimensional bar code technology in their ID cards or driver's licenses, and the two-dimensional bar code technology has also been adopted in the passports of the Hong Kong Special Administrative Region of China.
In addition, there are also examples of using two-dimensional barcode technology to solve data input and prevent forgery and deletion of forms in customs declaration forms, long-distance freight bills, tax statements and insurance registration forms.
Two-dimensional bar code has also been initially applied in some areas of China, such as CPA certificate, automobile sales and after-sales service.