Barcodes have become a familiar part of reality for us. We take them for granted, meeting on packages of various goods, booklets, documents, street signs and signs on cultural sites. Did you know that there is a big difference between linear and two-dimensional barcodes? What is a QR code? We suggest you sort it all out together.
What is a barcode?
First, let's decide on a key concept.
A bar code is a certain sequence of black and white stripes that represents the given information in a form convenient for reading by technical devices. Usually the same information for the client, visitor, consumer is duplicated in printed text near this image.
The scope of linear and two-dimensional barcodes today is unusually wide - it is trade and library science, warehouse accounting and security systems, mail and document processing, various technological processes in production.
The history of a useful invention began in 1938. It is associated with the names of three young inventors - B. Silver, ND Woodland, D. Johanson. Interestingly, Woodland painted the first barcode model in the sand. As he later admitted, his invention was inspired by Morse code (in fact, Woodland simply extended the dots and dashes) and optical tracks (a way to read encrypted information). A US patent was received by scientists in 1952.
Linear and two-dimensional
Line codes were used first. Here the information can be read by the scanner in only one direction - horizontally. The most common symbolism is EAN, which you can see in the picture below.
The main advantage of linear bar codes is their simplicity. Hence, an inexpensive technique is required for reading. But a drawback comes directly: a similar code can store very little information (20-30 characters). Most often this is a specific numerical sequence.
And what is a two-dimensional barcode? This is a special character that stores much more data (up to several pages of text). Accordingly, scanners read it immediately in two directions - vertically and horizontally. The main advantage: allows you to accurately and quickly read a large amount of information.
A two-dimensional barcode is applied to products and objects in two ways: typographic (printed on the label, packaging, plate, etc.) and using special self-adhesive stickers (printed on special printers).
Scanners
What is a barcode scanner? Special devices that are able to correctly read information from a linear or two-dimensional variety. The scanner lights up the strokes with its clarifier, after which it reads the picture that is visible to it. It is important for the instrument to determine the presence and sequence of black bars in the image.
If the device is not equipped with a built-in decoder (a unit for decrypting encoded information), then it transmits to the receiver a certain series of signals corresponding to the characteristics of black and white elements. An external decoder, a receiving element is designed to read them.
If the barcode scanner already has a decoder, then this element decrypts the information, and then transfers it to the cash register, computer in accordance with the interface signals.
Note that today, scanners of two-dimensional codes can be not only special devices, but also ordinary smartphones. It is enough to download the appropriate software to the device. By the way, at present, many gadgets are able to read QR codes without installing special applications - just point the camera at a symbol.
Varieties of two-dimensional codes
It is a common misconception that printing a two-dimensional barcode is printing a QR code. But this is not so. QR is one of the varieties of barcodes, but their variety is not limited to them.
Parsing linear and two-dimensional barcodes, we consider the existing varieties of the latter:
- PDF417.
- DataMatrix
- QR code.
- Aztec Code.
We invite you to get acquainted with each of the varieties in more detail.
PDF417
The developer of this code is Symbol Technologies. The invention of PDF417 came to the world in 1991. What does its name mean? PDF stands for Portable Data File. But the number is more interesting. Each such barcode will consist of 17 modules. The latter, in turn, have four strokes and spaces. The result is 417.
It can be argued that such a block, in fact, will still be one-dimensional. The aim of the creators was to simplify the compilation of code and subsequent decryption. However, this applies only to special scanners. Programs on mobile devices so far do not do very well with reading PDF417 - they "see" it through time.
Where can such an invention be found in modern reality? In Russia, most often they are labeled with alcoholic beverages. PDF417 can also be seen on Aeroexpress tickets (electric trains in Moscow, running between stations and airports).
DataMatrix
A two-dimensional matrix barcode was invented by International Data Matrix. In 2005, it was acquired by Siemens Corporation. A great influence on this development had the above invention. Today, matrix code is described by ISO standards. Its use is free, does not imply royalties.
DataMatrix will be a two-dimensional matrix consisting of black and white modules and dots. They are represented by an even number of vertically and horizontally. Blocks can be from one to several pieces. In each of them, there must be two intersecting lines in the form of the letter L. This is a “search pattern” that helps to understand the character orientation for the reader.
The other two sides of the block will consist of alternating black and white dots - they indicate to the scanner the size of the code. The error correction standard here is based on the Reed-Solomon algorithm (if the code is damaged, it allows you to restore up to 30% of the information).
The main advantage of the invention is its small size. See for yourself: in a space of 2 mm 2 you can actually encrypt information with a volume of 50 characters. DataMatrix can be applied to the surface in many ways: engraving, laser, inkjet printing and so on. The standard shapes are rectangle and square.
Giants such as BMW, Siemens, Mercedes, Intel, Philips, NASA use DataMatrix. In Russia, you can find this two-dimensional barcode on a medical prescription, sick leave.
QR code
Before us is the most common form of matrix two-dimensional code. The name comes from the English Quick Response - "quick response." The invention belongs to the Japanese company Denso-Wave. The code was introduced to the public in 1994. By the way, in Japan, he received the greatest distribution. More than half of mobile subscribers use it. Perhaps the reason is that the QR code "understands" the characters of the cana.
The use of this barcode is free and free worldwide - both for individuals and legal entities. However, an official standard for the symbol does not exist. Its sizes can range from 11 to 177x177 modules.
Mandatory components A QR code is three large squares surrounded by empty space. They help the scanner to determine the position of the symbol, to correct the distortion of perspective. You can see another small square - it is necessary to determine the orientation of the service areas. In addition, the code requires free space around itself - from 2 to 4 modules (depending on version).
Using QR Code
A two-dimensional barcode on a QR tax return is far from the only application of this useful invention. Let's see how things are in the world:
- Advertising and marketing. By clicking on the link on the billboard, the user can go to view the promotional video, the customer’s virtual store. In this case, the goods can actually be ordered right there on your smartphone.
- Tourism, museums, exhibitions. On popular attractions, signs with this code often appear. It helps to go to a brief historical background, a page on Wikipedia, to find out other useful information.
- Ticketing. It is enough for the user to save the QR code provided when purchasing a ticket on the Internet to his mobile device. Next, the picture on the screen of the gadget is applied to a special reader at the station or at the airport.
- Business cards. All information about the owner is concisely encrypted in the code. What is convenient, when scanning it, data about a person is automatically saved in the gadget.
In Russia, one more innovation can be observed - two-dimensional barcodes on receipts for utility bills. They can be decrypted by a regular smartphone with the installed QR code reader.
Aztec code
In many ways similar to the previous one. The creators, Welch Allyn, do not hide this. Their main task was to combine in their invention the best of existing developments. In 1995, it was presented to the public. At first the code was patented, but then it was opened for free use.
The symbol is only square, contains from 15 to 151 modules. They can be combined into blocks. Key elements: target, orientation elements, data layers, snap grid.
In the Russian Federation, Aztec Code prints S7 Airlines on its tickets. For these purposes, he was also selected by the main international air transport association.
Two-dimensional codes, as well as linear ones, turned out to be indispensable in modern reality. Their main advantage is in coding large volumes of information.