QR code (abbreviated from Quick Response code) is the trademark for a type of matrix barcode (or two-dimensional barcode) first designed in 1994 for the automotive industry in Japan. A barcode is a machine-readable optical label that contains information about the item to which it is attached. In practice, QR codes often contain data for a locator, identifier, or tracker that points to a website or application. A QR code uses four standardized encoding modes (numeric, alphanumeric, byte/binary, and kanji) to store data efficiently; extensions may also be used.
QR Code has error correction capability to restore data if the code is dirty or damaged. Raising this level improves error correction capability but also increases the amount of data QR Code size. To select error correction level, various factors such as the operating environment and QR Code size need to be considered.