2Dkoodeja

2Dkoodeja refers to a class of two-dimensional barcodes, which encode information in patterns arranged in two dimensions rather than along a single linear sequence. Like other barcodes, they are read by image sensors and decoded by software, usually using a camera on a smartphone or a dedicated scanner. The two-dimensional arrangement allows them to store substantially more data in a given physical size and to include error correction, making them readable even when partially damaged or obscured.

Most 2D codes are designed to be robust to printing imperfections and wear. They use error correction codes such as Reed-Solomon to recover data. Scanning can be done at varying distances and angles, but legibility improves with proper contrast and lighting.

Common formats include QR codes, Data Matrix, Aztec, PDF417, and MaxiCode. QR codes are the most widely used and can encode URLs, text, contact information, or small binary payloads. Data Matrix is valued for high density on small items. Aztec codes support compact layouts without a separate finder pattern. PDF417 is a stacked format that can store larger blocks of text or data, and MaxiCode has specialized use in shipping and logistics.

Applications include product labeling, ticketing, mobile payments, inventory management, and advertising. They are scanned by consumer devices and embedded in websites and apps. Limitations include dependency on printing quality, the need for compatible scanning software, and potential privacy or security concerns when linking to sensitive information.

The development of 2D codes began in the late 1990s with the creation of QR codes by Denso Wave, and has since been adopted worldwide across manufacturing, retail, transportation, and services.