An efficient classification and rendering method using tagged distance maps

Several high-speed volume rendering methods generate spatial data structures for speedup. Although they are useful for improving rendering speed, much time may be required to regenerate them. We propose an efficient classification and rendering method that supports fast classification. While original space-leaping needs to perform distance transformations for all voxels, our method modifies the values of some parts of the entire map by assigning predefined tag values when a voxels transparency is changed. The rendering algorithm is an extension of the space-leaping method and it determines the next sampling position by interpreting the values of those tagged voxels. This allows us to reclassify the volume quickly and to render datasets without loss of image quality.