Research On Digital Watermarking Model And Algorithm For Raster Geographic Data

Raster Geographic data, a main part of geo-spatial data, plays an important role in thenational economy, national defense construction and human life. With the accelerating process ofraster geographic data digitalization and network, its security problem has become increasinglyserious, data security incidents emerge in an endless stream, such as data leakage, illegal usage,copyright infringement and so on. However, rely solely on traditional data security technologyand the current laws and regulations, suchlike phenomenon cannot be effectively curbed.As a rising frontier technology in the information security field, the digital watermarkingtechnology is becoming more and more crucial in the security area of raster geographic dataprotection. Based on this demand-driven, combining with the data feature, precisioncharacteristics and application requirements of raster geographic data, applying some pertinentmathematical tools, in-depth research on raster geographic data digital watermark technologywas conducted in this paper. The specific research results are as follows:(1) In combination with the characteristics of raster geographic data, the feature of digitalwatermarking technology for raster geographic data was analyzed, which focused on the majordifference between the natural image watermarking technology and the raster geographic datawatermarking technology. The attacking methods of raster geographical data watermarking weresummed up, their different effects on the raster geographic data watermarking algorithm and thecorresponding countermeasures were explored.(2) Two kinds of binary raster geographic data watermarking algorithm were proposed.Based on the characteristics of binary raster data watermarking embedding, by introducing theidea of Run-Length Encoding (RLE) and modifying the run length of the encoded data, a binaryraster geographic data watermarking algorithm based on the run length was proposed. Byanalyzing the variation characteristics of the blocking raster data in the geometric transformationprocess, an anti-geometric transformation binary raster geographic data watermarking algorithmwas presented. The two algorithms effectively solved the problems of the low watermarkingcapacity and the poor robustness of current binary raster geographic data watermarkingalgorithms.(3) A watermarking model for transform domain raster geographic data was established.From the design perspective of transform domain watermarking algorithm, combining with thecharacteristics of raster geographic data, a new watermarking embedding and detection modelfor raster geographic data was built, which adapted to the transform domain, being of goodreference and guidance significance for the design of transform domain raster geographic datawatermarking algorithm. Under guidance of the proposed model, a raster geographic data watermarking algorithm based on wavelet transform was designed and implemented.(4) Based on the watermarking feature of raster geographic data in the splicing and cuttingprocess, a corresponding watermarking algorithm was proposed. Under the direction of themodel advanced, aiming to further improve the algorithm robustness and reduce the maximumwatermarking error, a robust watermarking algorithm for geometric transformation for rastergeographic data in transform domain was presented; then taking it as a prototype algorithm andintroducing the idea of quad-tree block recursive judgment, an anti-splicing raster geographicdata watermarking detection method was designed; finally, an anti-cutting raster geographic datawatermarking algorithm was proposed based on the precision characteristics of raster geographicdata.(5) Oriented to multi-level distribution, a raster geographical data watermarking modelwas constructed. Based on the in-depth summary and analysis of the status of geospatial datamulti-level distribution and its security risks, an ideal multi-level distribution oriented rastergeographical data watermarking model was constructed, which preferably solved the problemssuch as the flow direction identifier of raster geographic data, file access control, data copyrightprotection and use track in the multi-level distribution process.(6) A byte stream-based raster geographic data watermarking algorithm was established.Based on the fully dissection of the respective advantages and disadvantages of data encryptiontechnology and digital watermarking technology, combining with the storage and flowcharacteristics of raster geographic data and introducing the data encryption idea into the designof watermarking algorithm, a byte stream-based raster geographic data watermarking algorithmwas built. The algorithm provides a good solution for the flow direction identifier of rastergeographic data in the multi-stage circulation process, the access control and other issues.(7) Three kinds of multi-level watermarking algorithm for raster geographic data wereproposed. Adopting the quantization interval division strategy, the watermarking informationsegmentation strategy and the raster geographic data blocking strategy respectively, accordingly,a quantization division-based, a watermarking information segmentation-based and a datablocking-based multi-level watermarking algorithm for raster geographic data was proposed.Those three watermarking algorithms effectively solved the data multi-stage copyright protection,flow direction tracking and other problems in the multi-level distribution oriented rastergeographic data watermarking model.(8) On the basis of the studied watermarking models and algorithms, using theobject-oriented thought in the designing and developing process and adopting the interface-oriented programming, a watermarking prototype system for raster geographic data wasperformed.