Effective transfer function for interactive visualization and multivariate volume data

Transfer function strongly influences the quality of volume rendering. With transfer function, the information of interest in volume data can be effectively differentiated and highlighted. In this paper, we present a simplified LH histogram-based transfer function design method to interactively visualize the multi-boundary of volume data sets. Boundary classified based on conventional LH histogram is shared by both of materials that form it, which would add the thickness of the boundary. To overcome the drawback, f-LH histogram is proposed to classify and visualize each side of boundary. Some simulation and medical applications which require visualization often produce multiple values per sampling point or voxel in the so called multivariate data. Since feature of interest in the data set can not be properly classified by any single variable itself of the voxel, we further design an effective multidimensional transfer function to visualize multivariate field data.