What is QR code?
{{complex|date=November 2023}} [[File:QR_code_for_mobile_English_Wikipedia.svg|thumb|A QR code for the [[Uniform Resource Locator|URL]] of the [[English Wikipedia]] Mobile main page]] A '''QR code''' ('''quick-response code''') is a type of [[2D|two-dimensional]] [[Barcode|matrix barcode]]. [[Japan|Japanese]] company Denso Wave invented it in 1994 for labelling automobile parts.<ref>{{Cite journal|last=Hung|first=Shih-Hsuan|last2=Yao|first2=Chih-Yuan|last3=Fang|first3=Yu-Jen|last4=Tan|first4=Ping|last5=Lee|first5=RuenRone|last6=Sheffer|first6=Alla|last7=Chu|first7=Hung-Kuo|date=2020-09-01|title=Micrography QR Codes|url=https://ieeexplore.ieee.org/document/8632711|url-status=live|journal=IEEE Transactions on Visualization and Computer Graphics|volume=26|issue=9|pages=2834–2847|doi=10.1109/TVCG.2019.2896895|issn=1077-2626|pmid=30716038|archive-url=https://web.archive.org/web/20210421010504/https://ieeexplore.ieee.org/document/8632711/|archive-date=21 April 2021|access-date=21 April 2021}}</ref><ref>{{Cite journal|last=Chen|first=Rongjun|last2=Yu|first2=Yongxing|last3=Xu|first3=Xiansheng|last4=Wang|first4=Leijun|last5=Zhao|first5=Huimin|last6=Tan|first6=Hong-Zhou|date=2019-12-11|title=Adaptive Binarization of QR Code Images for Fast Automatic Sorting in Warehouse Systems|journal=Sensors|language=en|volume=19|issue=24|pages=5466|bibcode=2019Senso..19.5466C|doi=10.3390/s19245466|pmc=6960674|pmid=31835866|doi-access=free}}</ref> A QR code has a square, which contains other elements. There are black squares. These are arranged in a grid. Some of the parts are not filled, usually they are white. Some parts of the code are markers. These markers help with reading and decoding the information. Usually, the code is read by an imaging device, such as a camera. The information in the image is then decoded. QR codes have [[Reed–Solomon error correction]]. This means that even if parts of the code cannot be decoded, or they are wrong, the code can still be used. The required data are then extracted from patterns that are p