We present a novel mesh representation scheme exploiting the characteristics of triangle strips, called progressives strips, which gives rendering-efficient triangulation data at the rendering stage in a graphics system such as progressive transmission where the mesh topology changes continuously. Progressive strips consist of a set of triangle strips simplified to the base mesh and a set of refinement steps required to recover incrementally the original mesh at full resolution. We also propose an improved triangle strip filtering algorithm and the encoding of strip-edge collapses in order to reduce efficiently the redundant triangles and the amount of refinement information, both of which may increase as the mesh degrades. Our approach increases the overall graphics performance by reducing the amount of data sent to the graphics pipeline.

In this paper, we propose a new fragile watermarking scheme that can be used to verify three-dimensional (3-D) polygonal models by detecting unauthorized alterations. In order to generate a binary watermark sequence, we combine a binary random sequence generated by the user key with a binary logo sequence using the bit-wise exclusive OR operation. The binary watermark sequence is embedded into 3-D triangle strips by perturbing their vertex coordinates. The proposed watermarking scheme can identify specific locations that have been changed. Changes of the vertex coordinates in the watermarked 3-D model are reflected in the extracted watermark image, which indicates the attacked area. Experimental results demonstrate that we can detect various modifications of the watermarked 3-D model: translation, rotation, scaling, randomization of points, polygon simplification, geometry compression, and local deformation.