基于有效裁剪被遮挡单元的非规则数据场体绘制算法  

Volume Rendering for Irregular Grids with Culling Effectively Occluded Cells

作　　者：孙文武[1] 吴恩华[1] 

机构地区：[1]中国科学院软件研究所计算机科学实验室,北京100080

出　　处：《计算机学报》2001年第3期292-295,共4页Chinese Journal of Computers

基　　金：国家自然科学基金! (6990 3 0 0 9)

摘　　要：提出了一种被遮挡单元的裁剪算法 ,以加速非规则数据场的体绘制过程 .在基于一组平行切割平面的体绘制方法上 [7] ,新算法通过对图像不透明度缓冲区中的值进行求平均操作 ,并将所计算的结果存储在一个与不透明度缓冲区同样大小的平均不透明度缓冲区中 ,使得只需根据每一数据单元重心投影点在平均不透明度缓冲区中的值 ,就可得到此数据单元的可见性 ,从而有效裁剪掉被遮挡单元 ,降低需处理的数据量 ,加速体绘制过程 .In object-order volume rendering, it is possible that some image area become opaque when some cells are projected. Those cells whose projections are within opaque image area have no contribution to result image. In this paper, an algorithm for culling cells occluded is proposed to accelerate volume rendering for irregular data set. Irregular data set is rendered by incremental slicing. During rendering we use an average opacity buffer by averaging the opacity buffer with a box filter with the size, which equals to the maximum among the distances respectively corresponding to the maximal distance from the gravity of each cell to its vertices, the value of pixel in this average opacity buffer represents the average opacity of all pixels within a neighborhood of the dimensions with the size of box filter. Then, the visibility of each cell can be determined by indexing the value of the gravity projection of the cell in the average opacity buffer. If the value of the gravity projection of a cell in the average opacity buffer equals to 1.0, the cell is fully occluded, accordingly culled, or if partially occluded, accordingly projected. Thus, the amount of data needed to be processed can be reduced and volume rendering is accelerated.

关 键 词：非规则数据场 体绘制 裁剪 算法 图像处理 计算机 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]