MERGING CELLS:AN EFFICIENT BLOCK PROJECTION ALGORITHM 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 from interactive. 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 exploits the 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 into blocks. The paper gives cell merging criteria, discusses block projections process and the light contribution of blocks to final image. Finally, experimental results show that the new approach improves image quality and reduces rendering time.