A Research Of Digital Watermark For Product Design

With the rapid development of Information and Globalization, it is inevitable for theEnterprise to exchange document in the process of product design. Intellectual PropertyProtection is one important issue during the document exchange. The digital watermarktechnology is a very effective way to protect Intellectual Property. Nowadays, CADdrawing and3D mesh is widely used in the process of product design. Based on this, themain research work in the thesis is as follows.As for the need of copyright protection of the design document for the corporation, arobust watermark scheme is proposed. The proposed scheme embeds the watermark intothe geometric distribution of polyline, polygon and arc objects in the drawing. The objectsis cluster by using k-means++and the watermark bit is embedded into the geometricdistribution of the cluster. The geometric distribution is the normalized length distributionin a polyline object, the normalized area distribution in a polygon object, and the angledistribution in an arc object. Experimental results have verified that the proposed schemeis robust against common attacks.As for the need of integrity verification of the design document in the corporation, adeep study of fragile watermark is proposed. The proposed watermark algorithm embedsthe watermark information in two rounds. In the first round, some vertexes of the mesh arechosen as watermark vertexes and their x₁coordinates are modified to embed watermarkinformation, which makes them satisfy a special function with their neighbor vertexes. Inthe second round the x₂and x₃coordinates of the watermark neighbor vertexes aremodified, which makes them satisfy another special function with their neighbor vertexes.The proposed watermark algorithm extract the watermark information by check thefunction relation of a vertex and its neighbor vertexes. The chosen watermark vertexesduring the two rounds can cover the whole mesh and the two rounds embedding makes theintegrity verification of algorithm much better.