Research On The Digital Watermarking Scheme Of Digital Map

Digital map provides a great convenience for the field of measurements, and highly improves the efficiency and accuracy of information expressing. As side effects of the popularity of digital representation and distribution over network, some individuals or groups copied, transferred, amended and even sold the digital media without the permission of copyright owners, which greatly damaged the copyrights and commercial benefits of owners. Therefore, how to protect well the copyright of digital map in network environment has become a new problem of measurements filed. Moreover it has the value of study. As a new information security technology, digital watermarking technology has provided a solution for the problems of copyright protection, and the validity or integrity of the multimedia file have confirming.First, this paper presents the background and significance of the topic, and confirms the value of the study on digital watermarking scheme of digital map. The second section is about an overview of digital watermarking. The background and significance of the digital watermarking technologies, propose, features, principle, categories of digital watermarking technologies are discussed in detail in chapter II. Then attacks, evaluation criteria, as well as the scope of application are introduced. In the end of chapter II, a method of the topic is proposed. According the method of chapter II, this paper proposed two scheme for images of digital map field in chapter III and IV. The first scheme is about index images in the filed of digital map which have few color and clear boundaries. After analyzing existing algorithm this paper brings edge detection into digital watermarking, and proposes a scheme based on edge detection which modifies the pixels which are not noticeable. It neither brings new color in nor alter palette that can resist palette attack. The second scheme is for images whose pixels are continuous. This kind of images is taken by satellite, has big size and needs high ratio compression. This chapter presents the watermarking scheme based on DWT (Discrete Wavelet Transform) and quantification after introducing principle of DWT and JPEG2000. It resists JPEG2000 30:1 compression ratio that highly meets needs of measurement filed.Finally, the aspects need to be improved and the develop trends of digital watermarks are discussed.