- QR Code
A QR Code is a matrix code (or two-dimensional
bar code) created by Japanese corporation Denso-Wave in 1994. The "QR" is derived from "Quick Response", as the creator intended the code to allow its contents to be decoded at high speed. QR Codes are common in Japan, where they are currently the most popular type of two dimensional codes.
Although initially used for tracking parts in vehicle manufacturing, QR Codes are now used in a much broader context, including both commercial tracking applications and convenience-oriented applications aimed at mobile phone users (known as
mobile tagging). QR Codes storing addresses and URLs may appear in magazines, on signs, buses, business cards or just about any object that users might need information about. Users with a camera phone equipped with the correct reader software can scan the image of the QR Code causing the phone's browser to launch and redirect to the programmed URL. This act of linking from physical world objects is known as a hardlinkor physical world hyperlinks. Users can also generate and print their own QR Code for others to scan and use by visiting one of several free QR Code generating sites.
The Japanese standard for QR Codes, JIS X 0510, was released in January 1999, and a corresponding ISO International Standard, ISO/IEC 18004, was approved in June 2000. The standard was updated in 2006 ( [http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=43655 ISO/IEC 18004:2006] ).
"QR Code is open in the sense that the specification of QR Code is disclosed and that the
patentright owned by Denso Wave is not exercised." [ [http://www.denso-wave.com/qrcode/qrstandard-e.html] | Copyright] The Japanese website goes on to state that the term "QR Code" itself is a "registered trademark of Denso Wave Incorporated in Japan and other countries". [ [http://www.denso-wave.com/qrcode/index-e.html] | Trademark]
QR codes use the
Reed–Solomon error correction. The example below illustrates how the QR code handles distortion. Pixels were either added or removed from the original code to examine the borderline distortion level. Both of the altered images remain recognisable using "Level L" error correction.
Micro QR Code
Micro QR Code is a smaller version of the QR Code standard for applications with less ability to handle large scans.
There are different forms of Micro QR Code as well. The highest of these can hold 35 characters.
The design of QR makes it possible to incorporate eye-catching images of logos, characters, or photos into QR code, while calculating without losing any information of the code.
The colorized image represents the first 12 stanzas of
Lewis Carroll's, " The Walrus and the Carpenter". Encoded in binary mode with "Level M" error correction it contains approximately 2300 characters but, due to the density of the information, decoding it would require a high resolution image that is unavailable to many QR Code readers (particularly mobile phones).
* [http://www.denso-wave.com/qrcode/index-e.html Denso-Wave website]
* [http://harper.wirelessink.com/2006/03/29/mainstream-america-is-ready-for-bar-codes-converging-realspace-and-mobilespace/ Mainstream America is Ready for Bar Codes - Converging “Realspace” and “Mobilespace”]
* [http://qrcode.sourceforge.jp/ Java QR Code Open Source Decoder]
* [http://www.pedemonte.eu/pyqr/ Python QR encoder/decoder] , Python QR encode/decode module
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