Hierarchical Octree and Sub-Volume Texture Block Projection for GPU Accelerated Ray Casting Volume Rendering

Because of large volume data and slow speed in volume rendering, it proposes a new method for ray casting volume rendering using graphics processing unit (GPU). This algorithm firstly uses sub-volume texture block projection and then subdivides 3D volume texture while coding with hierarchical octree, projection information is used for rendering non-empty blocks from front to back. Sub-volume texture blocks including flag information of empty blocks and full blocks of volume data and skipping rendering and computation of empty blocks are used to accelerate ray casting algorithm along the ray direction with projection information of sub-volume. It decreases further subdivision of empty blocks and increases efficiency of octree coding. The experiments results show that this method can speed up at least 2.59 times during rendering on GPU and achieve good rendering effects.