The Research Of Digital Watermarking Technology Based On Discrete Wavelet Transformation And Image Sharing

The development and popularization of the multimedia and Internet technology provide great conveniences to getting and spreading digital products. Although, the digital products are easily copied and the reproductions are very similar as the original ones, the digital products'security problems is becoming heavier and heavier. It became a pop international research questions that how to protect the digital products'copyright effectually. As an effectual means to protect the digital products'copyright, the digital watermarking technology is being researched and used popularly. This technology embeds the watermarking which indicates the author or the copyright owner's information of the digital products into the original medium through some algorithms. It doesn't affect the use of the original medium, but only needs a special detector to extract and read the watermarking information which is used for judging the medium's copyright owner if there is copyright dispute. In this thesis, a watermarking algorithm used for protecting copyright was designed. The main work includes several parts as following:(1) This thesis simply introduced the status of digital watermarking technology, systematicly expounded its main knowledge such as the concept, the model, the features, the classification, the application and so on.(2) A digital watermarking algorithm based on discrete wavelet transformation and image sharing was designed in detail and realized in this thesis. We determined to embed the watermarking into middle-frequency coefficients after analyzing the watermarking features of the spatial domain and the frequent domain and the features of the wavelet image. The chaos sequence is used to strengthen the watermarking's ability to resist attacks. We improved an image sharing algorithm based on matrix decomposition, and used it to share the watermarking which aimed at strengthening the watermarking's ability to resist the attacks toward password.(3) The simulate experiments and imitate attacks were did and their results were analyzed in this thesis. The results showed that the algorithm proposed in this thesis is effectual.