The Impact And Assessment Of Lithography Process For Holographic Watermark Security Information

The hologram watermark technology applied in the anti-fake of the printing has the advantage of easy recognition, low cost, green and safe.However the printing process of security operations that can’t be ignored will have attack to the hologram security information, and the different parameters of printing technology will lead to different effects to watermark information. The study of the influence discipline produced by the printing process parameters on the hologram security of information has a positive meaning that to improve the reliability of hologram security, stability and avoiding false judging to information. In this paper,starting from the lithographic process that is most widely applied to study the influences of line screen, dot shape and the substrate surface to hologram security information.Firstly, analyzed the principle of line screen, dot shape, and influence of the substrate on the print quality of the original digital reproduction combining the techniques and principles that lithography is based, for example, the dot imaging principle, ink coloring principle,selective adsorption principle. For the printing effect on image features,we proposed an image feature extraction method combining Haar wavelet decomposition and singular value decomposition, and determined the feature extraction method can be applied to identify the image content by the print-scanning experiments, and it can be applied to the initial certification testing to the will be extracted information.It introduced a wavelet domain hologram watermark security program, combining with DWT, Arnold scrambling, Bresenham algorithm and Fourier hologram technology, and described PSNR and NC that are two indicators for evaluating the watermark performance, and analysis the distribution of hologram watermark image in the host image.Finally, by designing the comparative experiments that the parameters of the printing are changing, studying the lithographic process parameters and the influence principle to the holographic watermark information, making the printing experiment of hologram watermark based on the DWT. In addition, by making the printing result quantitativeanalysis, about image quality and extracted watermark image quality,made the summarized assessment of influence principle on watermark information, obtained the optimization designing method on the holographic anti-counterfeiting watermark printing: Line Screen will not influence the quality of holographic extraction as long as they meet the minimum requirements to reproduce digital image tone of the watermark information, there is no need to increase the screen line when the demanding on the printing quality without an excessive level, which can reduce the production process controlling difficulty and decrease the cost.In this paper, the impact of the hologram lithography process watermark security information is studied, the results of basic research can lay the foundation of the further research on watermark printing security, this kind of basic research work also need more researchers to improved.