A Watermarking Method for Electronic Nautical Charts Based on Spatial Redundancy Relationship

Abstract

The invention discloses an electronic chart watermarking method based on space redundancy relation. The method comprises the following steps: reading a chart file and determining spatial position relation of all top points; storing top point sets on the line or forming an annular shape through encircling in the form of a chain table according to a connection relationship; converting watermark bitmap information into binary watermark character strings; reading node elements in the chain table and carrying out grouping in a manner that two adjacent nodes form a group; for each bit of watermark code, sequentially extracting the group, and embedding watermark information in a manner of embedding redundant objects to the subgroups in the chain table; establishing a secret key for watermark extraction; sequentially reading binary watermark sequence; obtaining a detection watermark bitmap through reading the binary watermark sequence; and comparing the detection watermark bitmap with the original watermark bitmap, carrying out similarity calculation, and outputting the chart file embedded with the watermark information. The method can keep electronic chart space topology relation lossless, effectively resist against illegal copying and maintain user copyright.

Description

technical field [0001] The invention belongs to the field of information processing of cartography and geographic information science, and in particular relates to an electronic chart watermark method based on spatial redundancy relationship. Background technique [0002] As a part of the digital map, the electronic chart is an important map resource that has gradually received widespread attention in recent years, especially as countries pay more and more attention to the development and utilization of marine resources. In addition, it has more important strategic value. For such an important digital resource, the research on copyright protection and information security technology is relatively backward. "A Wavelet Domain Digital Watermarking Technology for Copyright Marking of Nautical Charts" and "Research on Watermarking Technology of Two-Dimensional Electronic Nautical Charts under Dual Features" are currently retrieved literature on copyright protection of electronic ...

AI Technical Summary

Problems solved by technology

There are two reasons why there are few researches on the information security technology of electronic charts in academic circles: first, the value of charts is high, and the production and distribution are strictly controlled. Many researchers suffer from lack of sufficient resources and cannot carry out In-depth research; on the other hand, due to the sensitivity of some applied technologies in this field, many results have not been published in time

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