On Document Watermarking Algorithms Of Line-shift Coding And Zero-Watermarking

With the popularization of Internet, a lot of important information stored as documents are transmitted on the network, people can edit and modify text data conveniently if no protective measures for texts are taken. It is obvious that the research on the copyright protection of texts is no time to delay.This paper mainly studies watermarking embedding and extracting algorithms for digital document images according to their characteristics. First the basic concept, the current research and the application situations of digital document watermarking are described, then the existing algorithms and their features are analyzed. The emphases are focused on the space and the transform domain watermarking algorithms for digital documents.In the space domain, the line-shift coding of document watermarking algorithms based on binary text images is improved. The watermark is extracted by directly using boundary detection and the feasibility is tested.In the transform domain, zero-watermarking method is used in the document. Zero-watermark is constructed and detected through DCT-based and DWT-based approach. The attack simulation results are given. The feasibility and the effectiveness are tested...