A Digital Watermarking Algorithm for Spatial Vector Data Using Surjective Functions
Date Issued
2014
Date
2014
Author(s)
Chiang, Yi-Ting
Abstract
Along with the development of information technology (IE), duplication and
transmission digital files has become an easy job. Spatial vector data which belongs to
one important geospatial data format takes high cost of establishing, therefore owner’s
copyright protection become a critical issue. Digital watermarking is one of the
solutions for copyright protection, however most of the relative researches have focused
on multimedia data in recent years. Each format of data owns unique data structure
which has been protected by suitable algorithms. There are two purposes of digital
watermarking used for copyright protection: robust against attack and not affect the
usability of the original data. The way of watermark embedding can be categorized into
spatial domain and transform domain. The related works on watermarking for the
spatial vector data shows that the way of spatial domain is the ease of use but decreases
robustness, and the way of transform domain apply well on geometric transformations
while relatively weak in resistance capacity to partial variation. This research provide a
transformation method by relative azimuth angle of the connection of vertex and median
point, and embed watermark via surjective functions to overcome less redundancy and
reinforce the robust level. The experiments show that the proposed algorithm has high
robustness on watermarking and little influence on the quality of the spatial vector data.
Subjects
數位浮水印
空間向量資料
版權保護
映成函數
Type
thesis
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