QR Code
QR Code (Quick Response Code) is a two-dimensional matrix symbology having finder patterns on three of its corners.
There are three versions of QR Code symbols:
- Model 1: original version
- Model 2: enhanced version
- Micro QR
QR Code symbols can represent the following types of data:
- Numeric (digits 0 - 9)
- Alphanumeric
- 8-bit
- Kanji
QR Code symbol illustrates a QR Code symbol:
For a detailed description of QR Code symbols refer to the following industrial specifications:
- AIM International Symbology Specification 97-001
- ISO/IEC 18004:2000 Information technology - Automatic identification and data capture techniques - Bar code symbology - QR Code
- ISO/IEC 18004:2005 Information technology - Automatic identification and data capture techniques - QR Code 2005 barcode symbology specification
The first two specifications apply to Model 1 and Model 2 QR Code symbols. The third specification applies to Model 2 and Micro QR Code symbols. The following summary is taken from the ISO/IEC 18004:2005 specification.
“It is necessary to distinguish four technically different, but closely related members of the QR Code family, which represent an evolutionary sequence.
- QR Code Model 1 was the original specification for QR Code and is described in AIM International Symbology Specification 97-001.
- QR Code Model 2 was an enhanced form of the symbology with additional features (primarily the addition of alignment patterns to assist navigation in larger symbols), and was the basis of the first edition of this International Standard.
- QR Code 2005 (the basis of this edition of this International Standard) is closely similar to QR Code Model 2 and, in its QR Code format, differs only in the addition of the facility for symbols to appear in a mirror image orientation, for reflectance reversal (light symbols on dark backgrounds) and the option for specifying alternative character sets to the default.
- The Micro QR Code format (also specified in this International Standard), is a variant of QR Code 2005 with a reduced number of overhead modules and a restricted range of sizes, which enables small to moderate amounts of data to be represented in a small symbol, particularly suited to direct marking on parts and components and to applications where the space available for the symbol is severely restricted.
QR Code 2005 is a matrix symbology. The symbols consist of an array of nominally square modules arranged in an overall square pattern, including a unique finder pattern located at three corners of the symbol (in Micro QR Code symbols, at a single corner) and intended to assist in easy location of its position, size and inclination. A wide range of sizes of symbol is provided for together with four levels of error correction. Module dimensions are user-specified to enable symbol production by a wide variety of techniques.
QR Code Model 2 symbols are fully compatible with QR Code 2005 reading systems.
Model 1 QR Code symbols are recommended only to be used in closed system applications and it is not a requirement that equipment complying with this standard should support Model 1. Since QR Code 2005 is the recommended model for new, open systems application of QR Code, this International Standard describes QR Code 2005 fully, and lists the features in which Model 1 QR Code differs from QR Code 2005 in Annex N.”