2d code
The marking of goods and services is commonly done with the one-dimensional bar code. Since the data density of bar codes is relatively low, various applications use two-dimensional codes whose data capacity is a hundred times that of bar codes. In 2D codes, a distinction is made between composite codes, stacked codes and matrix codes.
Composite codes are composite codes consisting of a bar code and a 2D matrix code. A composite code consists of two different codes arranged one below the other and is therefore also called a double code. The double code has the disadvantage that the barcode reader must support both code symbols, the barcode and the 2D matrix code. Other multiple codes are stacked codes, known as code blocks, which consist of several bar codes arranged one below the other line by line.
An example of a stacked code is PDF417. Well-known and lesser-known 2D matrix codes include the Data Matrix code, Semacode, QR code, BeeTag, VeriCode, Aztec code, MaxiCode and the VS code. In total, there are probably over 50 different 2D codes.
Data capacity and error compensation of 2D codes
2D codes have a much higher data capacity and are sufficiently insensitive to error-prone reading. They have a square structure and consist of a two-dimensional bit pattern. To enable 2D codes to be read in any position, they have markings for position determination. In addition, they work with differently staggered error corrections that reproduce the coded data even when most of the 2D code is no longer readable. For error detection and correction, they use Error Detection And Correction( EDAC).
The 2D code is used, for example, for electronic stamps, on admission tickets, train tickets or for marking production parts. Such parts can be monitored throughout their entire life cycle, including production and supply chain management. This so-called Direct Part Mark Identification( DPMI) is defined in the DPMI specifications and 2D code guidelines.
Reading 2D codes
2D codes are scanned using 2D code scanners or the digital cameras ofsmartphones, which have built-in 2D code readers. As a result, 2D codes are increasingly being used in product advertising in ads or on posters. This is referred to as mobile tagging. In these applications, the cell phone scan simultaneously triggers an action. For example, the captured 2D code can be used to read the provider's data or other address data directly into the address book, or in the case of an Internet address( URL), it can be used to establish a direct connection to the provider's website. 2D codes, like other identifiers, are part of Automatic Identification and Data Capture( AIDC).
There are various 2D code readers, 2D code generators and 2D code development tools that are provided free of charge for private use.