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Print-Scan Resistant Two-Level QR Code

Aiming at increasing the capacity of Quick Response (QR) codes that are resistant to print-and-scan(P&S) process, this paper proposes a two-level QR code that replaces the black and white modules in the standard QR code with specially designed modules. First, at the encoder side, during the generation of two-level QR code, error correction code (ECC) and stream encryption are used for the second-level message to ensure security. Then, taking the second-level message into consideration, the black and white modules in the standard QR code are replaced with the specific modules designed. At the decoder side, the first-level message can be decoded and recognized by the standard QR code scanner. The second-level message can be extracted with the help of demodulator and secret key. Finally, considering the impact of the P&S process on two-level QR code images, four low-pass textured patterns are designed for white and black modules. Experimental results demonstrate that the proposed algorithm is superior to the reference method in terms of high storage capacity and resistance to P&S process.