Innovative volume rendering using 3D texture mapping

Most texture mapping involves a backward projection which maps from screen space back into the texture data. Bilinear/trilinear interpolation is usually used to sample data in the 2D/3D textures. To accelerate texture mapping, traditional graphics hardware requires a complete copy of the texture image at each parallel computation node to allow all nodes to operate in parallel. This paper introduces a new backward projection approach for rendering volume data, treating the volume as a 3D texture. It employs an innovative parallelization scheme in which a computation node operates on a subvolume, thereby avoiding the need to store the whole volume at each node. This approach has been implemented on the Kubota Kenai Denali workstation, a high performance system for imaging and 3D graphics. It currently supports functions for maximum intensity projection, multiplanar reformatting, volume resampling, ray sum, and isosurface rendering. Progressive refinement schemes can be utilized to reduce sampling rate and to realize interactive rendering speeds.