The hottest two-dimensional bar code and its appli

Two dimensional bar code and application

I One dimensional bar code (1D barcode)

one dimensional bar code only expresses information in one direction (generally horizontal), while it does not express any information in the vertical direction. Its certain height is usually for the convenience of reader alignment. 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:

small data capacity: about 30 characters

can only contain letters and numbers

the bar code size is relatively large (low space utilization)

the bar code cannot be read after it is damaged

II Two dimensional bar code

a bar code that stores information in two-dimensional space in horizontal and vertical directions is called two-dimensional bar code. As shown in Figure 1

Figure 1: one dimensional bar code and two-dimensional bar code

(I) classification of two-dimensional bar code

like one-dimensional bar code, two-dimensional bar code also has many different coding methods, or coding systems. In terms of the coding principle of these coding systems, they can generally be divided into the following three types (see Figure 2):

1 Based on the coding principle of one-dimensional bar code, the linear stacking two-dimensional code is produced by stacking multiple one-dimensional codes vertically. Typical code systems are code 16K, code 49, PDF417, etc

2. Matrix QR code is encoded in a rectangular space through the different distribution of black and white pixels in the matrix. Typical code systems include Aztec, Maxi code, QR code, data matrix, etc

3. Postal codes are encoded by bars of different lengths, which are mainly used for mail coding, such as Postnet and BPO 4-state

Figure 2: classification of two-dimensional bar codes

in many kinds of two-dimensional bar codes, the commonly used code systems are: data matrix, Maxi code, Aztec, QR code, vericode, PDF417, ultracode, code 49, code 16K, etc., see figure 3:

Figure 3: common two-dimensional bar code systems

among them:

data matrix is mainly used for the identification of small parts in the electronic industry, such as the back of Intel Pentium processor

maxi code is developed by United Parcel Service (UPS) for parcel sorting and tracking

aztec is launched by Welch Allyn company in the United States, which can accommodate 3832 numbers or 3067 alphabetic characters or 1914 bytes of data at most

next, we take PDF417 code as an example to introduce the characteristics and characteristics of two-dimensional bar code

IV Application of two-dimensional bar code

I) Applications in the transportation industry

a typical transportation business process usually goes through several processes: supplier --> freight forwarder, freight forwarder --> freight company, freight company --> customer, etc., and each process involves the processing of shipping documents. Shipping documents contain a lot of information, including shipper information, consignee information, goods list, transportation mode, etc. The premise of document processing is data entry. Manual keyboard entry has the problems of low efficiency and high error rate, which can no longer meet the requirements of modern transportation industry

two dimensional bar code provides a good solution in this regard. The content of the document is compiled into a two-dimensional bar code, which is printed on the delivery document. The two-dimensional bar code reader is used to scan the bar code in all links of the transportation business, and the information is entered into the computer management system, which is fast and accurate

in the United States, although EDI application has innovated the core part of the business process, it unfortunately ignores the key role in the process - the freight company. Many EDI messages are always late for freight forwarders, so that they cannot confirm the accurate shipping document information in time, which affects the generation of cargo transportation and customer documents

the American Freight Association (ATA) therefore proposed a paper EDI system. The sender compiles the EDI information into a PDF417 barcode label and submits it to the freight forwarder. By scanning the barcode, the information is immediately transmitted to the freight forwarder's computer system. All this happens at the right time and place, which greatly improves the efficiency of the whole transportation process

II) Application of ID card

the US Department of defense has printed PDF417 code on military ID card. The cardholder's name, military rank, photo and other personal information are compiled into a PDF417 code and printed on the card. Cards are used to manage access to important places and hospital visits

the advantages of this application lie in the real-time data collection, low implementation cost, the ability to read damaged cards (such as shooting), and the anti-counterfeiting of all parts made of composite materials

PDF417 code is also used in the resident identity card of Hong Kong Special Administrative Region of China. Other applications, such as business license, driving license, passport, temporary residence permit of floating population in Chinese cities, medical insurance card, etc., are also good application directions

III) Application of documents and forms

every broker of seimei insurance company in Japan brings a laptop when meeting customers. Each policy and agreement is made and printed on the computer. When they return to the office, they need to manually input the policy data into the company's mainframe

in order to improve the accuracy and speed of data entry, they compile the contents of the insurance policy into a PDF417 barcode while making the insurance policy and print it on the document, so that they can use a two-dimensional barcode reader to scan the barcode and enter the data into the host

other similar applications include: customs declaration form, tax declaration form, various application forms of government departments, etc

IV) Asset tracking

the leading edge of the U.S. industry 10 clearly shows that China steel pipe company has different types of pipelines in various regions that need maintenance. In order to track each pipe, they compiled the pipe number, position number, manufacturer, length, grade, size, thickness and other information into a PDF417 barcode, which was made into a label and pasted on the pipe. When the pipe is removed or installed, the operator scans the barcode label, and the database information is updated in time

factories can use two-dimensional bar codes to track production equipment; Hospitals and clinics can also use two-dimensional bar code labels to track equipment, computers and surgical instruments

v Hybrid code and its application

with the development of society, the progress of science and technology, the improvement of people's living standards, and the intensification of market competition, people's requirements for information continue to improve. One dimensional bar code in some of its traditional application fields, such as commerce, medicine, logistics transportation, etc., due to the limitation of information capacity (generally, it can only identify the identification number of items or businesses), has become increasingly unable to meet people's requirements. The continuous improvement of two-dimensional bar code technology is causing changes in these application fields

the United States UCC Organization (unified coding Committee) has introduced a new coding system - hybrid code, which is a combination of one-dimensional code and two-dimensional code, Among them:

* the components of one-dimensional code can be:

* UCC/EAN-128

* UPC/EAN

* reduced space symbol to promote the production, development and utilization of assessment log (RSS)

* the components of two-dimensional code can be:

* cc-a (a variant of PDF417 microcode dedicated to mixed code)

* cc-b (standard PDF417 microcode)

* cc-c (standard PDF417 microcode)f417)

* the one-dimensional bar code part contains the identification number, The two-dimensional barcode part contains supplementary information

* it can be read by linear CCD and laser scanner with grating in the future

1. The application of mixed code in logistics and transportation business

ucc/ean-128 is adopted and supplemented by two-dimensional barcode to provide information such as purchase order number, shipping order, route information, electronic backup of shipping notice, packaging, contents and batch number

2. The application of mixed code in drug circulation

use two-dimensional bar code to record supplementary information, which can provide expiration date to facilitate drug turnover, and record batch number for drug tracking

3. The application of mixed codes in the retail industry

marking batch numbers and expiration dates on food, especially fresh and frozen perishable things, can greatly improve the turnover efficiency of goods. The version and revision information of software and hardware can also be marked on electronic products

VI Two dimensional bar code reader

the reading equipment of two-dimensional bar code can be divided into:

* linear CCD and linear image reader can read one-dimensional bar code and linear stacked two-dimensional code (such as PDF417). When reading two-dimensional code, you need to scan the whole bar code along the vertical direction of the bar code, which is called "scanning reading". This kind of product is relatively cheap and has a good cost performance

* the laser reader with grating can read one-dimensional bar code and linear stacked two-dimensional code. When reading the QR code, aim the light at the bar code, and the raster element completes the vertical scanning without manual scanning

* image reading becomes milky white. Image reader takes barcode images by camera and analyzes and decodes them. It can read one-dimensional barcode and all types of two-dimensional barcode. It is a high-end device

Welch Allyn is one of the major barcode reading equipment manufacturers in the world. Its CCD technology, image reader technology and decoding technology are in the leading position in the world. Recently, she proposed a new concept of linear imaging technology. Based on advanced technology, wellin's two-dimensional bar code reading equipment has always led the world trend. Its main products include two series: it3800 and it4400