Distance Transfer Function Based Rendering

Transfer functions are fundamentals for direct volume rendering to visualize object through mapping optical properties to the voxel data values. One aspect of direct volume rendering which has received no attention in transfer function design is the use of voxel position in transfer functions. Often, there are features of interest in volume data that are visualized or not depending on their voxel positions. This paper aims to demonstrate the importance and power of voxel position dependent transfer function. The main contributions are followings: To introduce voxel position information into transfer function domain; To demonstrate the implementation of how to combine voxel position information into the rendering pipeline; And to show its important application fields in volume rendering. In order to make the rendering genuinely interactive, the fast rendering capabilities of modern graphics hardware is exploited. The presented approach is useful for focal region based volume rendering to depict data information.