Fast visualization of object contours by non-photorealistic volume rendering

In this paper ive present a fast visualization technique for volumetric dat a, which is based on a recent non-photorealistic rendering technique. Our n ew approach enables alternative insights into 3D data sets (compared to tra ditional approaches such as direct volume rendering or iso-surface renderin g). Object contours, which usually are characterized by locally high gradie nt values, are visualized regardless of their density values. Cumbersome tu ning of transfer functions, as usually needed for setting tip DVR views is avoided. Instead, a small number of parameters is available to adjust the n on-photorealistic display. Based oil the magnitude of local gradient inform ation as well as on the angle between viewing direction and gradient vector , data values are mapped to visual properties (color, opacity), which then are combined to form the rendered image (MIP is proposed as the default com positing stragtegy here). Due to the fast implementation of this alternativ e rendering approach, it is possible to interactively investigate the 3D da ta, and quickly learn about internal structures. Several further extensions of our new approach, such as level lines are also presented in this paper