Study Of Watermarking Technology Based On Two-Dimensional Barcode

With the rapid development of industrialized and information in modern society, barcode technology has been applied more and more widely, and its security requirements have become more sophisticated. PDF417 barcode is the most widely used barcode technology, and digital watermarking is an effective way to improve the information security. In order to improve the security of barcode technology, this thesis combined PDF 417 barcode with digital watermarking, and then proposed two new watermarking algorithms after analysis of existing algorithms. The main research work of this thesis is summarized as follows:1. First, this thesis systematically summarizes the composition, classification and characteristics of barcode, and introduce detailed the special structural features, technical requirements of PDF417 barcode which was used in the new algorithm. Second, this paper introduces the background, basic properties, composition and attack type of digital watermarking. At last, this thesis explains the spread spectrum technology detailly.2. A barcode watermark algorithm based on special structural feature was proposed. The watermark was embedded into the barcode through moderate expand the bar and space. As the change of bar and space is less than the allowing error, the reading of the original information in barcode will not be destroyed by watermarking. At the same time, the watermarking information was spread and mapped firstly before hidden in the barcode. Experimental results show that this algorithm has better invisibility, larger capacity and better robustness for the common attack compare to the exist algorithms.3. A barcode watermark algorithm based on resist local large stained attack was proposed. Based on the previous algorithm, this algorithm sliced the barcode firstly and then cycle embeds the watermark in order to avoid lower watermark extract rate due to local watermark serious damage. Experimental results show that this algorithm has better robustness in against local large stained and another attacks. In addition, this algorithm has better invisibility, larger capacity. Finally, this paper analyzes the difference between these two algorithms, and then summary their application.