1. Two-Level QR Code for Private Message Sharing and Document Authentication
Source: IEEE Transactions on Information Forensics and Security, Vol. 11, No. 3, pp , 2016.
Authors: Tkachenko Iuliia, Puech William, Destruel Christophe, Strauss Olivierm, Gaudin Jean-Marc, Guichard Christian
Speaker: Peng-Cheng Huang
Date: 9/18/2018

2. Outline Proposed Scheme Experimental Results Conclusions
Two Level QR (2LQR) Code Generation
Storage Capacity of 2LQR Code
Recognition Method
Experimental Results
Conclusions

3. Proposed Scheme (1/9) Two Level QR (2LQR) Code Generation (1/6)
A comparison of a) Standard QR code, with b) Proposed 2LQR code for private message sharing scenario and c) Proposed 2LQR code for authentication scenario.

4. Proposed Scheme (2/9) Two Level QR (2LQR) Code Generation (2/6)
Overview of 2LQR code generation steps.

5. Proposed Scheme (3/9) Two Level QR (2LQR) Code Generation (3/6)
Private message Mpriv encoding - q-ary ECC
Cyclic Code ：C[n,k,d]
ternary Golay Code ：G[11,6,5]

6. Proposed Scheme (4/9) Two Level QR (2LQR) Code Generation (4/6)
Private message Mpriv encoding - Textured Pattern Selection
Choose q patterns from a database of Q >> q textured patterns, which are binary and have the same density (ratio of black pixels)

7. Proposed Scheme (5/9) Two Level QR (2LQR) Code Generation (5/6)
Private message Mpriv encoding - Textured Pattern Selection
Let Si , i = 1, ... , q be the P&S degraded versions of textured patterns Pi , i = 1, ... , q
The Pearson correlation:
where:

8. Proposed Scheme (6/9) Two Level QR (2LQR) Code Generation (6/6)
Private message Mpriv encoding - Textured Pattern Selection

9. Proposed Scheme (7/9) Storage Capacity of 2LQR Code (1/1)
Storage capacity of the 2LQR code for QR code of size N × N modules, where n is the codeword length, k is the number of information digits, n −k is the number of parity-check digits.

10. Proposed Scheme (8/9) Recognition Method (1/2)
The overview of 2LQR code reading process.

11. Proposed Scheme (9/9) Recognition Method (2/2)

12. EXPERIMENTAL RESULTS (1/8) - 2LQR Code Generation
the ternary Golay code [11, 6, 5]
ratio of black pixels = 60%

13. EXPERIMENTAL RESULTS (2/8) - 2LQR Code Generation

14. EXPERIMENTAL RESULTS (3/8) - Message Extraction

15. EXPERIMENTAL RESULTS (4/8) - Storage Capacity Analysis

16. EXPERIMENTAL RESULTS (5/8) - Reading Capacities of First and Second Levels

17. EXPERIMENTAL RESULTS (6/8) - Reading Capacities of First and Second Levels
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18. EXPERIMENTAL RESULTS (7/8) - The Proposed 2LQR Code and Its Authentication

19. EXPERIMENTAL RESULTS (8/8) - The Proposed 2LQR Code and Its Authentication

20. Conclusions
These 2LQR code can be used for private message sharing scenario and document authentication at the same time. The proposed 2LQR code increases the storage capacity of the classical QR code (up to 28% )