通过区域块投影方法直接绘制三维数据场

直接的体绘制技术提供了在一幅图形内显示三维数据场各种信息的巨大潜力。然而，生成这样的图形是极其昂贵的，而且高质量图形的绘制远远达不到交互实现的水平。体元投方法之所以能引起人们的极大举是因为在处理过程中充分地利用了体元的空间连贯性。本文提出了一个更有效的体绘制方法：区域块投影方法（Ｂｌｏｃｋ Ｐｒｏｊｅｃｔｉｏｎ Ｍｅｔｈｏｄ）。这一算法不仅利用了体元的空间连贯性而且还充分地利用了数据场函数值分布的

MERGING CELLS:AN EFFICIENT BLOCK PROJECTIONALGORITHM FOR DIRECT VOLUME RENDERING

Direct volume rendering techniques present a huge potential for displaying a great amount of information in 3D data sets within one image. However, generating such an image is extremely expensive and rendering for high quality pictures is far frominteractive. Compared with ray casting, cell projection method for volume rendering attracts people's more interests due to its exploitation of spatial coherence of cells. This paper proposed a new volume rendering approach: Merging Cells. It not only exploitsthe spatial coherence of cells but employs fully the spatial coherence of function distribution to partition a volume into a number of subvolumes, so that the function varies slowly over each subvolume. Then adjacent cells within each subvolume are merged intoblocks. The paper gives cell merging criteria, discusses block projections process andthe light contribution of blocks to final image. Finally, experimental results show thatthe new approach improves image quality and reduces rendering time.