The Watermark Technology Research Based On Digital Image And Sub-surface

The daily life and work of people are becoming more and more digitalized and networked with the rapid development of computer and internet technology. Spread of a large number of private data and popularity of electrical commerce make the traditional method of copyright protection and technology of data security face great challenge and some difficulty which isn't conquered easily. Digital watermark technology is proposed in such situation. Digital watermark is a new and practical technology of information hiding and copyright protection. It has caused great concern and has been developing rapidly in recent years.Digital watermark technology confirms the ownership of the data through embedding secret information to original data. The embedded watermark may be a paragraph of text, labels, serial number and so on. Watermark is normally invisible or unconscious, which combines closely with the original data and hide itself in the data, becomes an inseparable part of source data, and survives after experiencing some operation which can't damage practical or commercial value of source data. Therefore, the research on digital watermark technology has its significance for copyright protection of digital media.This paper takes the static digital images and three-dimensional grid model as the study object, on the basis of concluding development background of digital watermark and the framework of the basic theoretical, proposes two approaches of embedded watermark: one is watermarking algorithm based on the human visual system HVS and discrete wavelet transform DWT, the other is mesh watermarking technology algorithm based on subdivision surface.The major work in this paper is listed as follows:First, on the basis of looking up a large number of domestic and foreign literatures which are about the digital images and three-dimensional grid watermark, introduces the basic concepts about the digital watermarking, as well as the main field of application, summers up the current domestic and international study status and development dynamic about digital watermark technology.Second, discusses the basic knowledge about the wavelet transform, elaborates simple functional model of the human visual system HVS referenced in the digital watermark, as well as loop subdivision mode of subdivision surface.Then, on the basis of theory above, this paper proposes a digital watermark algorithm based on the human visual system HVS and discrete wavelet transform DWT. First, the algorithm proposed carries on three-tier wavelet transform to original image, then considers properties of brightness and texture masking about human visual system ,compromises contradiction between the hidden nature and the robustness of the watermark, searches suitable location for watermark's embedding, eventually extracts watermark by inverse transform. Experiment shows that the algorithm has good stability, practical significance for the copyright protection of digital products.Finally, doing something useful to explore and try the digital watermark in the 3D mesh, proposes a mesh watermarking technology based on subdivision surface. Grid will be the initial iteration several times to enable Grid Vertices enough, then takes some vertexes coordinates in order to embed watermark, takes the grid embedded with watermark as a new initial grid. Experiments show that the algorithm can effectively resist multiple attacks to 3-D grid.