【摘要】 由有限的二维断层图象系列获得三维图象,内插过程是必不可少的.本文对常用的两种内插方法一线性插值和动态弹性插值进行了实验的对比和分析.更多还原

【Abstract】 In many scientific and technical endeavors , a 3D object must be reconstructed from serial cross sections .such as CT images , to enhance the comprehension of objective structure or to facilate its automatic manipulation and analysis.The main tasks in a computer 梐ided reconstruction process usually consist of extracting the region of interest (or their contours) in all the cross 梥ectional images and forming surfaces or volumes between the contours of successive slices, if two consecutive slices are not closely spaced , the interpolation process is needed to obtain the interslices making the smoothness of the reconstructed surfaces.Two interpolation schemes,linear and dynamic elastic interpolation have been proposed. Linear interpola-tion is only suitable for the situation when the distances between consecutive slices are small enough and the number of interslices is limited to one or two . Dynamic elastic interpolation provides a mechanism to generate iteratively a series of intermediate contours for filling gaps between start and goal contours. The basic concept of this method is to identify a "force field" acting on the start contour, trying to distort it to be similar to the goal contour . There are two main shortages of this method. First is very complex and time?consuming to find the feature points on each contour in the step of computing"force field". Second is very difficult to automatically determine several parameters in the formula of "force field". If these parameters are not well chosen, the results will not be satisfactory.In this paper ,we present a new interpolation method to overcome the shortages of the above two methods. The basic concept of this method is to proceed the interpolation procedure directly without extracting the contours of start region (SR ) and goal region (DR). The first step is to find each line in SR corresponding to that in GR iteratively based on the histograms of SR and GR and then a line mapping table is established. The second step is to obtain the line in the interslice between the corresponding lines in SR and GR with looking up the line mapping table. The main advantage of this positon mapping interpolation is its high speed. The experimental result is presented to demonstrate the performance of this method in high speed. This method has been successfully used in our research work- the 3D reconstruction from CT images.更多还原