Automatic center-path finding in real 3-D data set is the key problem in realization of automatic navigation. Many methods have been proposed

but most of them are either quality depressed or time expensive. In this paper

after summarize the main existent methods

a new 3D center path finding algorithm base on two distance fields is proposed: Between any given start-point and end-point which can be connected

the source distance field base on the start-point and the boundary distance field base on the boundary are established. Through the co-restriction of the two-distance field

a center path that connects the start-point and end-pint can be found. In order to enhance the effect of navigation

a cubic B-spline curve is used to smooth the path. The algorithm is realized on PC platform and two medicine image date sets are used for test. Computer time and path finding results are shown in Section 4. As compared with onion peeling algorithm and Dijkstra's Single Source Shortest Path Algorithm

the result shows that the algorithm not only can get fast speed and high quality result

but also has more flexibility. The application in Virtual endoscopy is also shown in the end of the paper.