High-speed volume rendering using redundant block compression

Presents a novel volume rendering method which offers high rendering speed on standard workstations. It is based on a lossy data compression scheme which drastically reduces the memory bandwidth and computing requirements of perspective raycasting. Starting from classified and shaded data sets, we use block truncation coding or color cell compression to compress a block of 12 voxels into 32 bits. All blocks of the data set are processed redundantly, yielding a data structure which avoids multiple memory accesses per raypoint. As a side effect, the tri-linear interpolation of data coded in such a way is very much simplified. These techniques allow us to perform walkthroughs at interactive frame rates. Furthermore, the algorithm provides depth-cueing and the semi-transparent display of different materials. The algorithm achieves a sustained frame generation rate of about 2 Hz for large data sets (/spl sim/200/sup 3/) at an acceptable image quality on an SGI Indy workstation. A number of examples are shown.