Two-stage textured-patterns embedded QR codes for printed matter authentication

Abstract

The popular use of high quality printing and scanning equipment makes it easier to counterfeit important printed matter, such as important document, anti-counterfeit label on merchandise, packaging, etc. Previously, methods such as textured image, two-level quick response (2LQR) code, fractional-order spatial steganography, etc., have been used for printed matter authentication. In this paper, a simplified model is proposed to analyze the variation of the correlation of textured-patterns (hereinafter called patterns) after the print-and-scan (P&S) process, which gives accurate mathematical descriptions of the information loss during P&S processes. Based on previous theoretical results, we propose the two-stage textured-patterns embedded QR (2SQR) codes for printed matter authentication, which are based on 2LQR codes and sensitive to P&S process. In the generation process, the stage two (S2) patterns are introduced, which are the corresponding P&S version of the textures in the 2LQR codes, i.e., stage one (S1) patterns. Then part of the S1 patterns in 2LQR codes are replaced with the corresponding S2 patterns, resulting in the 2SQR codes. In the authentication process, the 2SQR indicator is used to eliminates the need for the original image, which eliminates the storage and retrieval process of the original images. Experiments show that, compared with the 2LQR codes, the 2SQR codes significantly improve the performance in distinguishing the authentic codes and their copied version.

An Anti-Counterfeiting Architecture for Traceability System Based on Modified Two-Level Quick Response Codes

“…The correlation coefficient (or correlation) is an indicator to describe the information loss. The following proposition has been proved in [32]:…”