Digital Watermarking Method for Vector Map Data Against Conformal Projection Transformation

Abstract

The invention relates to a method for digital watermarking of anti-constant projection transformation vector map data, which can effectively solve the problem of completely detecting the copyright mark of the watermark when the original projection information is unknown, and improving the execution efficiency and accuracy of watermark detection. The identified binary image is used as a watermark, encrypted, and then converted into a one-dimensional watermark coding sequence; input the vector map data to be embedded in the watermark, and extract linear elements in sequence according to the file storage order; perform spread spectrum processing on the watermark; Perform polyline forward transformation on the feature, and express the anchor point with length variable and angle variable; embed watermark to the angle variable of the anchor point of the linear element; perform inverse polyline transformation on the linear element, restore the anchor point of the linear element to the plane coordinate representation Carry out watermark detection on vector map data containing watermark information, the method of the present invention is simple, easy to operate, improves watermark detection efficiency, and ensures safe application of vector maps.

Description

technical field [0001] The invention relates to the fields of geographic information science and information hiding, in particular to a digital watermarking method for vector map data resistant to conformal projection transformation. Background technique [0002] Vector map data is an important national infrastructure, and the development of the network has expanded the application range of vector map data, but the ensuing security problems have seriously limited the application of vector map data. The acquisition process of vector map data is very complicated, requiring a lot of manpower, material resources, and financial resources. The convenience of data copying poses a great threat to the copyright of vector map data. Therefore, data copyright protection becomes the key to expanding the application range of vector map data. links. Digital watermarking technology is a cutting-edge technology for data copyright protection. It utilizes data redundancy and embeds copyright ...

AI Technical Summary

Problems solved by technology

None of the existing watermarking methods can directly detect the watermark logo from the projected data. The usual processing method is to inversely transform the watermarked data to the projection when the watermark is embedded, and then use the watermark detection method to detect the watermark.

[0005] Although the above method can detect the watermark to a certain extent, due to the different projection models and parameter selection, multiple projections will cause loss of data accuracy and affect the watermark detection to a certain extent; reverse transform the data to the original projection , will greatly reduce the execution efficiency of watermark detection; in addition, in most cases, the watermark detector cannot obtain the original projection information, so it cannot detect the watermark from the data after projection transformation, the execution efficiency is low, and the accuracy rate is low

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