A 2D barcode is a graphical representation of a sequence of numbers or letters. It was designed to be easy to print, compact in size and readily read by a scanner. The barcode identifies an item, person or other object by a unique number that potentially links to information within a database. This allows the scanning of a barcode to bring up prices, product descriptions or medical patient information, depending on how the scanning system works. Unlike its one-dimensional counterpart, a 2D barcode is capable of storing far more information, primarily because it uses a grid-like array of dots instead of simply a sequence of lines.
The 2D barcode evolved from the one-dimensional design that was developed to help in managing the inventory of grocery stores. Over many decades it went through several changes as technology slowly caught up with the concept. It finally took collaboration between several large companies to make the concept work and spread it throughout retail outlets around the world.
The 2D barcode is an advance over the one-dimensional barcode for several reasons. It is able to represent more than just numerical data and instead can represent letters, numbers and other characters. It also contains a method of error correction to ensure the code was read into a computer correctly.
In sensitive industries, a 2D barcode also can contain different methods of encryption. One of these involves obscuring what might otherwise appear as normal data by dispersing meaningless symbols or patterns into the image. Another method is to encrypt the information and then re-encrypt it before printing, providing an added layer of security against the information being read by an unauthorized person.
Some 2D barcodes are capable of storing more than 7,000 characters in their printed design. This has allowed them to be used to store and transmit far more information than a standard one-dimensional barcode. They can be used to store information on personal identification cards and medical charts or to transmit text files. They have even emerged as advertising vehicles, because they can be scanned by mobile devices loaded with the appropriate software. This is possible because the information can be transmitted solely through the barcode itself without the need to index it into an existing database.
Variations of the 2D barcode have been developed. These include 3D barcodes that are physically etched onto the surface of materials during manufacturing and then read by determining the difference in the depth of the field. Radio-frequency identification (RFID) removes most of the optical aspects of a 2D barcode and instead uses a printed circuit to transmit barcode information to receivers that can read it. Despite these developments, one-dimensional and 2D barcodes remain the most widely used.