针对细节高度复杂模型的特点,提出一种视点相关的渐进传输方法.并根据人的视觉特征,算法将模型表示为多分辨率的四边形参数面片和表面法向细节纹理.该算法利用法向映射提高传输和绘制的效率,然后随着视点的变化动态细化和传输当前视点下轮廓部分的参数面片信息,从而最大限度地减少了模型传输时面片的数量.参数面片的结构规则,面片之间关联性低,因此能够按任意顺序高效地传输,从而实现真正的视点相关传输,并可以采用有效的编码方法对其结构和几何信息进行压缩.实验结果表明了该算法的有效性,特别适合于表面细节复杂的表面模型的交互传输和绘制.
This paper presents a novel approach for the progressive transmission of highly detailed surfaces interactively. Based on the characteristics in human vision, 3D surfaces are converted into the hierarchical quadtree in parameter space and a normal texture atlas. By taking advantage of normal mapping, only the silhouette to current viewpoint is refined and transmitted, and consequently the amount of patches needed to transfer each frame is greatly reduced. The structure of the representation is simple, so efficient compression scheme can be applied to encoding the hierarchical topological structure. At the same time, the parametric patches can be transmitted in arbitrary order due to their regular connectivity, so the truly view-dependent transmission could be achieved in high efficiency. Experiment results show that the approach proposed is feasible and highly efficient in meeting the requirement, especially to those models with highly detailed surfaces.