An efficient 3D visualization system has not only fast volume rendering algorithms but also effective navigation methods. Rendering speed is one of key technologies in most 3D visualization applications. We exploit software, Pentium 4 and graphics hardware technologies, such as threshold segmentation, Intel SIMD and 3D texturing, to obtain interactive volume rendering on a standard PC without specialized expensive hardware. Path planning is essential in many 3D visualization applications, such as virtual endocopy, in order to accelerate exploring. There are three major types of methods to extract the navigation path from a 3D data set, including manual, 3D distance transform and thinning based techniques. 3D thinning is a desirable method to extract skeletons of objects, but it has some severe problems to be solved. It is time consuming with discontinuity and small branches. An effective encoding and coordinates transform based scheme is presented to generate a look up table of 3D thinning templates to speed up path extracting, and a two-pass tracking technique is followed to trim the small branches of skeletons. Tri-pass cubic Bezier technique is proposed to decrease large curvatures caused by discrete representation of path. A smooth and C 1 continuity navigation path is thus produced by our algorithms. Following this path, the camera moves and rotates smoothly without any dithering. Our system is very useful and can be widely applied due to full utilization of the existing inexpensive capabilities of PCs.
An interactive 3D medical visualization system based on a light field display