Watermarking three-dimensional polygonal models

The advantages of digital media such as the Internet and CD-ROMs lie in the fact that their contents are easy to duplicate, edit, and distribute. These advantages, however, are double-edged swords, because they also facilitate unauthorized use of such contents. Data embedding, which places information into the contents themselves, is an approach to address this issue. Embedded information can be used, for example, for copyright protection, theft deterrence, and inventory. This paper discusses our work on embedding data into three-dimensional (3D) polygonal models of geometry. Given objects consisting of points, lines, polygons, or curved surfaces, the data embedding algorithms described in this paper produce polygonal models with data embedded. Data are placed into 3D polygonal models by modifying either their vertex coordinates, their vertex topology (connectivity), or both. A brief review of related work and a description of the requirements of data embedding is followed by a discussion of where, and by what fundamental methods, data can be embedded into 3D polygonal models. The paper then presents data-embedding algorithms, with examples, based on these fundamental methods.