Analysis:

Bar code is a set of bars and empty symbols arranged according to certain coding rules, which is used to represent information composed of certain characters, numbers and symbols. Bar code system is an automatic identification system composed of bar code symbol design, production and scanning reading.

Bar code coding method:

There are many kinds of bar codes, and there are about twenty common coding systems, including:

Code39 (standard code 39), Codabar code (Kudbar code), Code25 (standard code 25), ITF25 code (cross code 25), Matrix code 25 (matrix code 25), UPC-A code, UPC-E code, EAN- 13 code (EAN- 13 code). China postal code (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/kloc-0).

At present, EAN code and UPC code are widely used in the world 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 most widely used in management field), ITF25 (which is most widely used in logistics management field), Codebar (mostly used in medical and book fields), Code93, Code 128, etc. 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 various bar code application systems, Code39 can be composed of numbers and letters * * *, so it is widely used in the internal management of various industries. Codebar code is also widely used in blood banks, libraries and photo studios.

In addition to the one-dimensional bar codes listed above, two-dimensional bar codes have also developed rapidly and been applied in many fields.

Introduction to common bar codes:

EAN code:

EAN code is a kind of commodity bar code formulated by ean international organization, which is used all over the world. There are two kinds of EAN code symbols: the standard version (EAN- 13) and the abbreviated version (EAN-8), and the common commodity bar codes in China are equivalent to them. 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 United States Uniform Coding Committee, 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 bar code, which 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.

Bar 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, the barcode on a commodity can only hold 13 digits (EAN- 13 code) * *, and more information can only be supported by the commodity database. If there is no pre-established database, such bar code is meaningless, thus limiting the application scope of bar code to some extent. Because of this, 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, strong 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 and so on. , mainly divided into stacked or layered codes and chessboard or matrix codes.

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 * * * 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, the QR 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 of documents. Therefore, it can be widely used in passports, identity cards, driver's licenses, military officers' cards, health certificates, insurance cards and so on.

PDF4 17 technology has been used in driver's licenses, US military licenses and military medical licenses in more than ten states, such as Arizona, USA, several years ago. Personal information and photos on certificates are encoded in two-dimensional bar codes, which can not only realize automatic reading of identity cards, but also effectively prevent the occurrence of forged certificates. Many countries, such as the Philippines, Egypt, Bahrain and so on. The ID card or driver's license also adopts the two-dimensional bar code technology, and the passport of the China Special Administrative Region also adopts the two-dimensional bar code technology.

In addition, in customs declarations, long-distance freight bills, tax bills and insurance registration forms, there are also examples of using QR code technology to solve data input and prevent forgery and deletion of forms.

Two-dimensional code has also been initially applied in some domestic fields, such as certified public accountant certificate, automobile sales, after-sales service and so on.