| This paper described a method of digital watermark embedding based on the spatial structure of the PDF417 2-D bar code. According to the implementation, this paper described the details, and given an example, and finally, analyze the results.2-D bar code is an open system, so it is weak in security and confidentiality. But the digital watermarking technology is born for security and confidentiality. Therefore, the combination of these two technologies can make 2-D bar code through its own limitations. The pixel of the image of 2-D bar code is either black or white, so the ordinary watermarking will bring gray-scale to the image, and make it more visible. So, the algorithm of the spatial structure is better. This method can embed information into the junction of two layer of the bar code by changing some specific pixels, thus we can enhance the security of 2-D bar code and will not affect the identification of the bar code. The results show that while the encoding information of the bar code is large enough, a large-capacity watermark can be embedded by this method, and has little effect on the bar code image, far less than the tolerance range, and will not affect the identification.This method can be applied to digital copyright protection, or in the case of less demanding of fault tolerance, to increase the storage capacity of the 2-D bar code. As a reference of the algorithm, the code was given in the appendix, and the key data structure and the key operations were described in the section of algorithm analysis.This paper also mentioned another digital watermarking algorithm of the 2-D bar code, and did a simple comparison of those two. Finally, this paper analyze the occasion where this method can be used, and discussed the place where can be improved and the possible following research, and give a inference that 2-D bar code and the technology around it will have bright prospects in China. Key words:2-D bar code, PDF417, digital watermarking, spatial structure... |
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