Vector map watermark method based on space geometric features

Abstract

The invention provides a vector map watermark method based on space geometric features. The vector map watermark method based on the space geometric features comprises the following steps of reading a vector map file; filtering out redundant rendering information; reading a data structure of a vector map object according to three basic map layers such as points, lines and regions; scanning watermark bitmaps and converting the watermark bitmaps into a binary sequence; determining an embedding length of a unit object; determining the scale of a watermark carrier gather; optimizing a map layer object gather; sequentially reading a set watermark coding sequence and writing the set watermark coding sequence at the tail of positioning information; extracting watermark codes in a space relation object by using a secret key; and generating watermark bit maps according to the binary watermark sequence and the sizes of the watermark bitmaps. The similarity between watermarks and the original watermarks is calculated and detected, and the map file cannot be damaged, zero loss of precision of an algorithm can be implemented on the basis that integrity of contents in a map is guaranteed, a vector data compression resistant effect can be achieved, and error rate is low.

Description

technical field [0001] The invention relates to a vector map watermarking method based on spatial geometric characteristics. Background technique [0002] Digital watermarking technology is a recognized method for copyright protection of digital products. In 1996, the first International Symposium on Information Hiding was held at the Newton Institute in Cambridge, England, marking the birth of information hiding, and the research on digital watermarking technology, one of the main branches of information hiding, has also developed rapidly. [0003] At present, there are few digital watermarking algorithms for vector maps, which mainly include two categories: the space domain and the frequency domain. The space domain algorithm is mainly to embed the watermark by slightly modifying the coordinate value. The algorithm is simple to implement, but the robustness is poor, and the damage to the map content is relatively large; the frequency domain algorithm uses mathematical met...

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Problems solved by technology

In a nutshell, the main reason is that there is a lack of an optimal selection strategy to guide the selection of embedded obje

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