A Robust Watermarking Algorithm for 2D CAD Engineering Graphics Based on DCT and Chaos System

摘要

As the computer aided design becomes widely used, the copyright violation of two-dimensional CAD engineering graphics urgently needs to be studied. But the current watermarking algorithms have many flaws such as lack of robustness, watermark capacity limitation, and so on. A new algorithm which based on DCT transformation and chaos system is proposed in this paper. The algorithm adopts DCT in watermark preprocessing to reduce the watermark information redundancy, and then classifies the entities of their handles through the chaos system to ensure the security of watermark. The watermark is embedded by modifying entity's line width slightly utilizing HVS characteristics. Experimental results show that the proposed algorithm has good imperceptibility; it's robust against operations such as translation, rotation, scaling, entity addition/deletion and combination of these attacks. The algorithm embeds the meaningful image into 2D CAD engineering graphic; it's useful in practical applications.