Enhancing the Data Capacity of QR Codes by Compressing the Data before Generation
CQR codes: Colored quick-response codes
Use multiplexing to increase information in QR code
Color QR Codes: Increased Capacity Via Per-Channel Data Encoding and Interference Cancellation
Secure QR code system
To increase data capacity of QR code using multiplexing with color coding: An example of embedding speech signal in QR code