Research On Digital Watermarking For Vector Geo-spatial Data Based On Dft

Vector geo-spatial data is the main format of spatial data and has important application in many fields, such as geo-science, navigation, surveying and mapping, military support etc. The security of vector geo-spatial data relates to technology cooperation, intellectual property, national security and so on. It is urgent to take credible technology to protect the security of vector geo-spatial data. As a new technology for protecting digital products, the digital watermarking technology has tremendous potential in copyright protecting. So it is necessary to study the digital watermarking technology for vector geo-spatial data.Based on the theory of discrete Fourier transform (DFT) and the characteristic of vector geo-spatial data for digital watermarking, the paper deeply researches the generating, embedding and extracting of digital watermarking based on DFT for vector geo-spatial data. The main works and creations are as the following:1. The background and current research of digital watermarking for vector geo-spatial data are analyzed, and the concept, classification and characteristic of digital watermarking are discussed. By analyzing the advantages of DFT in digital watermarking for vector geo-spatial data, the content and method of the research are brought forward.2. A digital watermarking algorithm for vector geo-spatial data based on DFT amplitude is designed. After analyzing digital watermarking generating, vector geo-spatial data transforming, digital watermarking embedding and extracting, the availability, imperceptibility, and robustness of the algorithm are confirmed by experiment.3. A digital watermarking algorithm for vector geo-spatial data based on DFT phase is designed. Considering the limitation of the algorithm, the autocorrelation detection is used to make sure the practicality.4. The digital watermarking algorithms based on DFT phase and DFT amplitude for floating vector geo-spatial data are studied by contrast. The experiment shows that the result of floating vector geo-spatial data is better than integer data by the algorithm based on DFT phase and the result by the algorithm based on DFT amplitude has few differences comparatively.5. A digital watermarking algorithm for vector geo-spatial data based on DFT is designed. The algorithm combines the advantages of both DFT phase algorithm and DFT amplitude algorithm, so can resist more kinds of attacks.Finally, the system design and main functions of the digital watermarking experiment system for vector geo-spatial data based on DFT are brought forward.