Watermarking Algorithm Applying to Small Amount of Vector Geographical Data

• Main Authors: TONG Deyu, ZHU Changqing, REN Na
• Format: Article
• Language: zho
• Published: Surveying and Mapping Press 2018-11-01
• Series: Acta Geodaetica et Cartographica Sinica
• Subjects: vector data; watermark capacity; compressive sensing; multi-segment quantization; robustness
• Online Access: http://html.rhhz.net/CHXB/html/2018-11-1518.htm

Aiming at the copyright protection especially for small amount of vector data,a watermarking algorithm based on compressive sensing and multi-segment quantization modulation have been proposed in this paper.In the procedure of watermark generation,binary copyright image is divided into blocks and measured by compressive sensing method to reduce the watermark redundancy.Measured results are then modulated into four values to reduce the watermark length and ensure the watermark recovery.In watermark embedding and detection,the principle of multi-segment modulation on the angle is studied by establishing the mapping relationship between watermark bit and modulation segment index.Hence this watermarking principle enables each vertex to carry more watermark bits in a robust way.Experiments have been conducted to verify the effectiveness of the proposed watermarking algorithm.By using the proposed algorithm,a binary copyright image is able to be embedded into the small amount of vector data,which consists of only 100 vertexes,and can be extracted clearly.The experiments also reveal that the watermark capacity of the proposed algorithm achieves above 7 bit for each vertex,which is higher than the comparison algorithms.Regarding the algorithms robustness,the proposed watermarking algorithm shows its superior robustness against attacks including vertex insertion,vertex deletion,vertex sorting,translation,rotation and scaling.In summary,the contradiction between high watermark capacity and small data volume has been solved by the proposed watermarking algorithm.