The BundleExplorer: A Focus and Context Rendering Framework for Complex Fiber Distributions

Advanced diffusion imaging enables the reconstruction of complex fiber configurations such as crossings or fannings. However, resulting visualizations often suffer from visual clutter which makes exploration challenging. This paper presents the BundleExplorer as a GPU-based focus and context rendering framework for diffusion data. A combination of a fiber encompassing hull and line rendering is proposed to provide insight into inner-bundle fiber configurations as well as to enable bundle crossing exploration. Visual clutter is reduced and information about the global bundle geometry is provided by using fiber encompassing hulls. At the same time important characteristics, such as individual trajectory courses, which are conventionally neglected when using hull visualizations, are revealed by cutaway techniques and enhanced line renderings. In addition, spatial features, the distance to the fiber hull, as well as functional features, i.e., the degree of anisotropy, are visualized using fiber color encoding. Different cutaway techniques using marker and view-dependent clippings are implemented in order to reveal focus information. Visual enhancements are used to indicate bundle intersections.