In 1D barcodes (or UPC barcodes), information can only be stored in one direction i.e. horizontally.
However, in a QR Code, information can be stored both horizontally and vertically. This allows QR Codes to store much more information.
To put this into perspective, a typical UPC barcode can store 20-25 characters whereas QR Codes have a maximum capacity of 7,089 characters.
QR Codes are made up of modules and there are 40 versions of QR Codes. Version 1 has 21 modules and the number of modules increase as the Version increases. Version 40 has 177 modules.
Another advantage of QR Codes over barcodes is Error Correction.
QR Codes were initially created for inventory management and were designed to handle factory wear, tear, and dirt. This was possible by adding Reed Solomon error correction to the codes, which is similar to the error correction used in Music CDs. This correction, which ranges from 7-30% depending on the level, allows customisation of the QR Code design.
Parts of QR Codes can be edited to include text or images and the error correction will still allow scanners to decode the information.
Detection by QR Code Scanner