Edit paragraph I. The history of the bar code

The bar code technology was first produced in the twentieth century in the windy twenties, born in the laboratory of the Westinghouse. An inventor named John Kermode eccentric character "whimsical" postal documents to achieve automatic inspection, that time on the application of electronic technology, every idea makes people feel very strange.

His idea was to mark envelopes with barcodes that contained information about the recipient's address, like today's ZIP codes. For this Kermode invented the earliest bar code marking, the design scheme is very simple (Note: This method is called the module comparison method), that is, a "bar" represents the number "1", two "bars "that the number" 2 "and so on. Then, he invented the bar code reading equipment composed of basic components: a scanner (able to emit light and receive reflected light); a method of determining the reflected signal bars and empty, i.e., the edge of the positioning coil; and the use of the method of determining the results, i.e., the decoder.

Kermode's scanner used a then-newly invented photocell to collect reflected light. The "null" reflected back a strong signal, and the "bar" reflected back a weak signal. Unlike today's high speed electronic component applications, the Kermode utilized a magnetic coil to determine the "bars" and "nulls". Like a child connecting a wire to a battery and wrapping it around a nail to hold paper, Kermode uses a coil with an iron core to attract a switch when it receives a "null" signal, and when it receives a "bar" signal, it releases the switch and When the "bar" signal is received, the switch is released and the circuit is turned on. As a result, the earliest bar code readers were very noisy. The switches were controlled by a series of relays, and the "on" and "off" were determined by the number of "bars" printed on the envelope. In this way, the bar code symbols were used to sort the letters directly.

Shortly thereafter, Kermode's collaborator, Douglas Young, made some improvements to the Kermode code.

The Kermode code contained a fairly low amount of information, and it was difficult to program more than ten different codes. The Young code used fewer bars, but utilized variations in the size of the spaces between the bars, just as today's UPC barcode symbology uses four different bar sizes. The new barcode symbology could encode one hundred different areas in the same size space, whereas Kermode could only encode ten different areas.

The invention of the all-encompassing bar code symbol by Norm Woodland and Bernard Silver was not first documented in the patent literature until 1949, and until then there had been no record of bar code technology in the patent literature and no precedent for putting it into practical use.

Norm Woodland and Bemard Silver's Norm Woodland and Bemard Silver's idea was to utilize the vertical "bars" and "voids" of the Kermode and YOung and bend them into a ring shape, much like an archery target. This way the scanner is able to decode the barcode symbol by scanning the center of the graphic, regardless of the orientation of the barcode symbol.

In the process of improving the patented technology, a science fiction writer, Isaac-Azimov, in his book, "The Naked Sun," tells of an instance where a new method of coding information was used to achieve automatic identification. At the time, the bar code symbol in the book looked like a checkerboard, but today's bar code professionals immediately recognize it as a two-dimensional matrix bar code symbol. Although this bar code symbol has no direction, orientation or timing, it clearly represents a high information density digital code.

It wasn't until 1970, when Iterface Mechanisms developed the "2D code," that there were affordable printing and reading devices for 2D matrix barcodes. At that time, 2D matrix barcodes were used to automate the typesetting process in newspapers. Two-dimensional matrix bar code printed on paper tape, by today's one-dimensional CCD scanner scanning and reading. CCD light emitted by the paper tape, each photocell aligned with a different area of the paper tape. Each photocell according to the paper with or without the printed barcode output different patterns, combined to produce a high-density information pattern. In this way a single character can be printed on the same size space as a single bar in the early Kermode code. Timing information was also included, so the whole process made sense. When the first system hits the market, a complete set, including printing and reading equipment, will cost about $5,000.

Shortly thereafter, with the continued development of LEDs (light-emitting diodes), microprocessors, and laser diodes, came the explosion of new identifiers (symbology) and their applications, which came to be known as the "bar-code industry". Today it is rare to find a company or individual who has not had direct contact with fast and accurate bar code technology. Because of the rapid technological advances and developments in this field, and because more and more applications are being developed every day, it won't be long before bar codes become as commonplace as light bulbs and semiconductor radios, and will make life easier and more convenient for each and every one of us.

Editorial paragraph two, bar code recognition principle

To be compiled in accordance with certain rules of the bar code into meaningful information, need to go through the scanning and decoding two processes. The color of the object is determined by the type of its reflected light, white objects can reflect a variety of wavelengths of visible light, black objects absorb a variety of wavelengths of visible light, so when the bar code scanner light source issued by the light in the bar code after the reflection of the reflected light irradiated to the bar code scanner inside the photoelectric converter, the photoelectric converter according to the strength of the different reflective light signals, converted into the corresponding electrical signals. According to the principle of difference, the scanner can be divided into light pen, CCD, laser three. Electrical signal output to the barcode scanner amplifier circuit to enhance the signal, and then sent to the shaping circuit will be converted from analog to digital signals. The width of the white bar and the black bar are different, and the corresponding duration of the electrical signal is also different. Then the decoder by measuring the number of pulses of digital electrical signals 0, 1 to identify the number of bars and empty. By measuring the 0, 1 signal duration to identify the width of the bar and empty. At this point the data obtained is still disorganized, to know the information contained in the bar code, it is necessary according to the corresponding coding rules (for example: EAN-8 code), the bar symbols into the corresponding digital, character information. Finally, the data is processed and managed by a computer system, and the detailed information of the item is recognized.

Edit paragraph III, the superiority of the bar code

1. Reliability. Barcode reading accuracy far exceeds the manual record, an average of every 15,000 characters will only be an error.

2. High efficiency. Barcode reading speed is very fast, equivalent to 40 characters per second.

3. Low cost. Compared with other automated identification technology, bar code technology requires only a small sheet of stickers and relatively simple optical scanner, the cost is quite low.

4. Easy to produce. Barcode writing is very simple, the production of only need to print, known as the "printable computer language".

5. Easy to operate. Barcode recognition equipment is simple and easy to use.

6. Flexible and practical. Barcode symbols can be manually entered into the keyboard, but also with the relevant equipment to form a recognition system to achieve automated recognition, but also with other control equipment to achieve the automated management of the entire system.

Edit paragraph four, bar code scanning

Bar code scanning needs scanner, scanner using its own light source irradiation bar code, and then use the photoelectric converter to accept the reflected light, the reflected light into a digital signal. Regardless of what rules are taken to print the bar code, are composed of a static area, the starting character, data characters and termination characters. Some barcodes have a check character between the data character and the termination character.

▲Static area: as the name suggests, the area that does not carry any information, plays a role in prompting.

▲Start character: the first character, with a special structure, when the scanner reads the character, it starts to read the code formally.

▲Data character: the main content of the barcode.

▲Check Character: Check if the read data is correct. Different encoding rules may have different checksum rules.

▲Termination character: the last character, as with a special structure, is used to inform the code scanning is complete, but also plays a role in just the checksum calculation.

In order to facilitate bi-directional scanning, the start and stop characters have an asymmetric structure. Therefore, the scanner can automatically rearrange the barcode information when scanning. Barcode scanner has a light pen, CCD, laser three

▲ light pen: the most primitive scanning method, you need to manually move the light pen, and also with the bar code contact.

▲CCD: CCD as a photoelectric converter, LED as the light source of the scanner. In a certain range, it can realize automatic scanning. And can read a variety of materials, uneven surfaces on the bar code, the cost is also relatively inexpensive. But compared with the laser type, the scanning distance is shorter.

▲Laser: laser as a light source scanner. It can be divided into several types, such as linear, full-angle and so on.

Linear: Mostly used in handheld scanners with a long range and high accuracy.

Full-angle: mostly horizontal, high degree of automation, in a variety of directions can automatically read the bar code.

Edit paragraph V. Advantages of bar code technology

Bar code is by far the most economical and practical kind of automatic identification technology. Barcode technology has the following advantages

A. Input speed: compared with the keyboard input, bar code input speed is 5 times the keyboard input, and can realize the "instant data entry".

B. High reliability: keyboard input data error rate of one in three hundred, the use of optical character recognition technology error rate of one in ten thousand, and the use of bar code technology error rate of less than one in a million.

C. Collection of large amounts of information: the use of traditional one-dimensional bar code can collect dozens of characters at a time of information, two-dimensional bar code can carry thousands of characters of information, and has a certain degree of automatic error correction.

D. Flexible and practical: bar code marking can be used as a means of identification alone, but also with the identification of equipment and related to the formation of a system to achieve automated identification, but also with other control equipment linked to achieve automated management.

In addition, bar code labels are easy to produce, there is no special requirements for equipment and materials, recognition equipment is easy to operate, does not require special training, and equipment is also relatively inexpensive.

Edit paragraph six, bar code coding rules

Uniqueness: the same specification of the same product corresponds to the same product code, the same product of different specifications should correspond to different product codes. According to the different nature of the product, such as: weight, packaging, specifications, smell, color, shape, etc., given different commodity code.

Permanence: Once the product code is assigned, it will not be changed again and is for life. When this product is no longer produced, its corresponding product code can only be set aside, can not be reused and re-allocated to other goods.

Non-meaningful: In order to ensure that the code has enough capacity to adapt to the needs of frequent product updates, it is best to use a meaningless sequential code.

Edit paragraph seven, bar code code system difference

UPC: (Uniform Product Code)

Can only indicate the number of A, B, C, D, E four versions Version A - 12-bit number Version E - 7-bit number The last bit of the check digit size is 1.5" wide by 1 " high, and the background should be with a clear Mainly used in the U.S. and Canada, for industrial, pharmaceutical, warehouse and other sectors. The UPC is mainly used in the United States and Canada for industrial, pharmaceutical, warehouse and other sectors. When the UPC is decoded as twelve bits, it is defined as follows: 1st bit = numeric identifier (already established by the UCC (Uniform Code Council). Bits 2-6 = Manufacturer's identification number (including the first bit) Bits 7-11 = Unique manufacturer's product code Bit 12 = Checksum (used for error detection)

Code 3 of 9 :

Capable of representing letters, numbers, and a few other symbols***43 characters: A - Z,0 - 9,-. $/+%,pace The length of the barcode is variable, usually using the "*" sign as the start and stop check digits without code density between 3 - 9.4 characters per inch, the white space is 10 times narrower, used in industry, books, and automated management of tickets.

Code 128:

Indicates high-density data, variable-length strings with checksums inside the symbols, available in three different versions: A, B, and C. Available in 128 characters in a set of three strings, A, B, or C. Used in industry, warehouses, and wholesale retail.

Interleaved 2-of-5 (I2 of 5):

Can only represent digits 0 -9 Variable length, continuous barcode, all bars and blanks represent code, first digit starts with a bar, second digit consists of blanks Blank area is 10 times wider than the narrower bar, used in wholesale goods, warehouses, airports, production/packaging identification, industry, barcodes have a high readability rate and can be applied to industrial, warehouses, retail wholesaling. The barcode has a high read rate, can be applied to fixed scanners for reliable scanning, and has the highest density of all 1D barcodes.

Codabar:

Can represent numbers 0 - 9, characters $, +, -, and four characters a, b, c d that can only be used as a start/stop character, variable length, no check digit, used in materials management, libraries, blood stations, and current airport parcel delivery, white space is 10 wide compared to the narrow bar, non-contiguous bar code, each character is represented as 4 bars and 3 blanks. expressed as 4 bars and 3 blanks.

PDF417 (two-dimensional code):

Multi-line bar code, do not need to connect to a database, itself can store a large amount of data, used in: hospitals, driver's license, materials management, transportation of goods, when the bar code is subjected to a certain degree of damage, the error correction can be made so that the bar code can be correctly decoded PDF417, is Symbol Technologies, Inc. in 1990 to develop products. It is a multi-line, continuous, variable-length symbology that contains a large amount of data. Each barcode has 3 - 90 lines, with a start, data, and end section for each line. Its character set includes all 128 characters and the maximum data content is 1850 characters.

One-dimensional barcodes express information only in one direction (usually horizontal), and do not express any information in the vertical direction, and their certain height is usually to facilitate the alignment of the reader.

The application of 1D barcode can improve the speed of information entry and reduce the error rate, but there are some shortcomings of 1D barcode:

* The data capacity is small: about 30 characters

* It can only contain letters and numbers

* The size of the barcode is relatively large (low space utilization)

* The barcode cannot be read when it is damaged

* The barcode can not be read after being damaged. Cannot be read when damaged

Bar codes that store information in two dimensions, horizontally and vertically, are called 2-dimensional bar codes.

Like one-dimensional bar codes, two-dimensional bar codes have many different encoding methods, or code systems. In terms of the coding principles of these code systems, they can usually be categorized into the following three types

1. Linear Stacked 2-Dimensional Bar Codes

These are generated by stacking multiple 1-D codes vertically on top of each other based on the coding principles of 1-D bar codes. Typical code systems such as: Code 16K, Code 49, PDF417 and so on.

2. Matrix 2D codes

are encoded in a rectangular space by different distribution of black and white pixels in a matrix. Typical code systems such as: Aztec, Maxi Code, QR Code, Data Matrix, and so on.

3. Postal Code

Encoded by bars of different lengths, mainly used for mail encoding, e.g. Postnet, BPO 4-State.

Among the many kinds of 2D barcodes, the commonly used code systems are: Data Matrix, Maxi Code, Aztec, QR Code, Vericode , PDF417, Ultracode, Code 49, Code 16K, etc. Among them:

* Data Matrix is mainly used in the electronics industry for the identification of small parts, such as Intel's Pentium processor printed on the back of this code.

* Maxi Code is developed by the United Parcel Service (UPS) for parcel sorting and tracking.

* Aztec was introduced by Welch Allyn (USA) and can hold up to 3832 numbers or 3067 alphabetic characters or 1914 bytes of data.

Below, we take PDF417 code as an example to introduce the characteristics and features of 2D barcode.

A) PDF417 Introduction

PDF417 code was invented by Dr. Yinjing Wang, a Chinese American, PDF is to take the English Portable Data File three words of the first letter of the acronym, meaning "Portable Data File". Because of 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 above four bars and four empty the total number of modules must be 17, so called 417 code or PDF417 code.

II) PDF417 features

1. Information capacity

PDF417 code can be expressed in addition to letters, numbers, ASCII characters, but also can express binary numbers. In order to make the code more compact and improve the information density, PDF417 has three formats when encoding:

* Extended Alphanumeric Compression Format Can hold up to 1850 characters;

* Binary / ASCII Format Can hold up to 1108 bytes;

* Numeric Compression Format Can hold up to 2710 numbers.

2. Error Correction Capabilities

One-dimensional barcodes typically 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, the correct information can be restored.

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 raster laser reader, linear and surface scanning image-based reader to read.

5. Adjustable size to adapt to different print space

6. Code open has formed an international standard, China has also developed a 417 code of the national standard.

Three) PDF417 error correction

The error correction function of the two-dimensional bar code is realized by repeating some of the information represented (redundancy). For example, in the PDF417 code, a line in addition to the information contained in this line, there are a number of other positions to reflect the characters (error correction code) of the information. 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.

PDF417's error correction capability according to the number of characters of the error correction code is divided into 0 to 8***9 level, see Figure 4, the higher the level, the more characters of the correction code, the stronger the corrective ability, the larger the bar code. When the correction level is 8, even if the barcode is 50% defaced it can be read correctly.

D) PDF417 several deformation

PDF417 there are several deformation of the code form:

* PDF417 truncated code

In the relatively "clean" environment, the bar code is very unlikely to be damaged, it can be omitted from the right side of the line indicator and the terminator can be reduced. reduce the terminator.

* PDF417 microcode

Further reduced 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 that contains multiple (1~99999) barcode chunks.

The advantages of two-dimensional barcode

From the above introduction, it can be seen that, compared with one-dimensional barcode two-dimensional barcode has obvious advantages, summarized in the following aspects:

I) greater data capacity

II) beyond the limits of the alphanumeric

III) the relative size of the barcode is small

IV) has a resistance to damage

Edit paragraph VIII, the production of bar codes

Application software

Label mx

CorelDRAW

Photoshop

Illustrator

Label mx belongs to the professional bar code generation and printing software. Set barcode generation, drawing design, label production, batch printing in one, can print fixed and variable data, CorelDRAW, Photoshop, Illustrator belongs to the professional drawing design software, in addition, Label mx can export the barcode as a vector image (.emf and .wmf) and CorelDRAW, Photoshop, Illustrator.

Second, the application software

EAN-13 general merchandise bar code generally consists of a prefix part, the manufacturer's code, the commodity code and check digits. Commodity bar code prefix code is used to identify the country or region of the code, the right to assign the code in the International Article Numbering Association, such as 00-09 on behalf of the United States, Canada, 45-49 on behalf of Japan, 690-692 on behalf of mainland China, 471 on behalf of China's Taiwan, 489 on behalf of the Hong Kong SAR. Manufacturer code is empowered in each country or region of the article code organization, China by the National Article Coding Center to give the manufacturer code. Commodity code is used to identify the code of the commodity, the right to assign the code is exercised by the product manufacturer itself, the manufacturer in accordance with the conditions of the provisions of their own decision on what kind of goods in their own use of which Arabic numerals for the commodity bar code. Commodity bar code with a check digit at the end to check the correctness of the commodity bar code in the left from the first l-12 digital code.

Full text:

A commodity bar code is a symbol that consists of a set of regularly arranged bars, blanks, and their corresponding characters to represent certain commodity information. The bar for the dark, empty for the color, for bar code reading equipment scanning and reading. Its corresponding characters by a set of Arabic numerals, for people to read directly or through the keyboard to the computer to enter data to use. This set of empty bars and the corresponding characters represent the same information.

Bar code technology is with the development and application of computer and information technology was born, it is a set of coding, printing, identification, data collection and processing in a new technology.

The use of bar code scanning is a major trend in future market circulation. In order to enable the free and wide circulation of commodities in the world, enterprises, whether they are designing and producing, applying for registration or using commodity bar code, must follow the relevant provisions of commodity bar code management.

Currently the world's commonly used code system has ENA barcode, UPC barcode, two-five barcode, cross two-five barcode, Kudumba barcode, three-nine barcode and 128 barcode, etc., and commodities on the most commonly used is the EAN commodity barcode.

EAN commodity bar code, also known as the Universal Commodity Bar Code, developed by the International Article Numbering Association, common in all parts of the world, is currently the most widely used in the international community of a commodity bar code. It is the most widely used commodity bar code in the world, and is currently used in China. EAN commodity bar code is divided into two types: EAN-13 (standard version) and EAN-8 (shortened version).

EAN-13 universal commodity bar code is generally composed of prefix part, manufacturer code, commodity code and check code. Commodity bar code prefix code is used to identify the country or region of the code, the right to assign the code in the International Article Numbering Association, such as 00-09 on behalf of the United States, Canada, 45-49 on behalf of Japan, 690-692 on behalf of mainland China, 471 on behalf of Taiwan, 489 on behalf of Hong Kong SAR. Manufacturer code is empowered in each country or region of the article code organization, China by the National Article Coding Center to give the manufacturer code. Commodity code is used to identify the code of the commodity, the right to assign the code is exercised by the product manufacturer itself, the manufacturer in accordance with the conditions of the provisions of their own decision on what kind of goods in their own use of which Arabic numerals for the commodity bar code. Commodity bar code with a check digit at the end to check the correctness of the commodity bar code in the left from the first l-12 digital code.

The code of the commodity bar code follows the principle of uniqueness to ensure that the commodity bar code is not duplicated worldwide, that is, there can only be one code for a commodity item, or a code can only identify a commodity item. Different specifications, different packaging, different varieties, different prices, different colors of goods can only use different commodity code.

The standard size of the commodity bar code is 37.29mm x 26.26mm, magnification is 0.8-2.0. When the printing area allows, should choose 1.0 times the bar code to meet the requirements of reading. The smaller the magnification of the bar code, the higher the printing accuracy requirements, when the printing accuracy can not meet the requirements, easy to cause bar code reading difficulties.

Since the barcode reading is achieved through the barcode of the bar and empty color contrast, in general, as long as the contrast (PCS value) to meet the requirements of the color can be used. Usually light colors are used for the empty color, such as white, orange, yellow, etc., and dark colors are used for the bar color, such as black, dark green, dark brown, etc. The best color combination is black bar, white bar, dark brown bar. The best color combination is black and white. According to the practical experience of barcode detection, red, gold, light yellow should not be used as the color of the bar, transparent, gold can not be used as the color of the empty.

The EAN-8 commodity bar code refers to the commodity bar code that the digital code used for identification is 8 digits, which consists of the commodity item code expressed in 7 digits and the check digit expressed in 1 digit.

The birth of the commodity bar code greatly facilitates the flow of goods, modern society has been inseparable from the commodity bar code. According to statistics, at present, China has 500,000 kinds of products using the internationally recognized commodity bar code. After China's accession to the WTO, enterprises in the international arena will win more space for activities. To be in line with international practice, to adapt to the needs of international trade and commerce, enterprises can not wait for the commodity bar code.

Some countries and regions (EAM) members of the bar code prefix code

United States, Canada 00-09 Israel 729 Denmark 57

(store code) 20-29 Venezuela 759 Norway 70

Japan 45-49 Uruguay 773 Switzerland 76

Belgium/Luxembourg 54 Bolivia 773 Spain 84

Finland 64 Chile 780 Austria 90-91

Sweden 73 Ecuador 786 New Zealand 94

Italy 80-83 Cuba 850 Slovenia 383

Netherlands 87 Czech Republic 859 Germany 400-440

Australia 93 Korea 880 Taiwan 471

Bulgaria 380 Singapore 888 Latvia 475

Croatia 385 Malaysia 893 Sri Lanka 479

Russia 460-469 Vietnam 977 Hong Kong 489

Estonia 474 Mexico 750 Cyprus 529

Lithuania 477 Colombia 770 Malta 535

Philippines480Peru775Portugal560

Greece520Argentina779Poland590

Macedonia531Paraguay784Hungary599

Ireland539Brazil789Mauritius609

Iceland569Slovakia858Albania613

Romania 594Yugoslavia 860Mainland China 690-692

Chinese-foreign joint ventures 693

South Africa 600-601Thailand 885France 30-37

Morocco 611India 890UK50

Turkey 619,869Indonesia 899

Edit Paragraph IX The smaller the magnification of the bar code, the higher the printing accuracy requirements, when the printing accuracy can not meet the requirements, easy to cause bar code reading difficulties.

Since the barcode reading is achieved through the barcode of the bar and empty color contrast, in general, as long as the contrast (PCS value) to meet the requirements of the color can be used. Usually light colors are used for the empty color, such as white, orange, yellow, etc., and dark colors are used for the bar color, such as black, dark green, dark brown, etc. The best color combination is black bar, white bar, dark brown bar. The best color combination is black and white. According to the practical experience of barcode detection, red, gold, light yellow should not be used as the color of the bar, transparent, gold can not be used as the color of the empty.