Research On Control Method Of Embedding Strength For The Digital Watermarking Based On Transformation Kernel

While global informationization advances by leaps and bounds, IT is developing at full speed with the multimedia information communication reaching unprecedented depth and breadth. The involving intellectual property of copyright problems is increasingly serious. The traditional of copyright protection and data safety technology is difficult to control the problem of intellectual property infringement which occurs frequently. A new interdisciplinary subject of digital watermarking technology was born in this context. Secret information is embedded the digital images, video and audio digital products, which does not affect the original data. The secret information includes the copyright symbol, the user serial number, the relevant product information, and so on. That is to protect the copyright of digital products, to prove the reliability of the product, to track piracy and to provide additional information of the product. The additional information can partially or entirely be recovered from the digital products.Firstly, this paper introduces the research background, significance, history and current situation as well as the research tools. Then, the basic principle of digital watermarking, the basic characteristics, classification, embedding and extracting and performance evaluation are narrated in detail. The classic algorithm and the general attack types of digital watermarking technology are expounded, and a brief introduction of the application fields and some current problems are presented. Thirdly, it is to introduce image unitary transformation in detail, to provide definition and mathematical representation of unitary transformation, to simply illuminate the useful properties of unitary matrix and transformation and to study some common transformation formulas and the transform kernel. Finally, this paper presents a controlling method of embedding strength for digital watermarking which is based on transformation kernel.At present, there are some methods to estimate the embedding strength of digital watermarking in certain image transforms, but have not been promoted to the level of the application of control embedding strength, and they are not suitable for switching among various transformations. In the additive embedding model, with the feature of transformation kernel a controlling method of embedding strength for digital watermarking, which is suitable for all kinds of unitary transformation to switch alternatively and based on the transformation kernel, is proposed. Research shows that this method can get more precise results in control of watermark transparency, and can get a satisfactory effect combining the objective and subjective evaluation index. Controlling method is simple and easy to understand, and the effect is accurate.