| In recent years, medical image visualization is one of the hot research issues. Its target is to reconstruct a three dimensional image from a series of consecutive two dimensional images. This technology provides doctors more clear and vivid image of organs or tissues. It also can make quantitative analysis, thus the accuracy of medical diagnosis can be improved. Therefore, the research on3D reconstruction algorithm has important significance.Marching Cubes (MC) algorithm is a classic algorithm of surface rendering, using triangular as intermediate geometric primitives for basic expression. This kind of expression is suitable for medical image data. It had a profound impact on the investigation of surface rendering. But the MC algorithm itself has some disadvantages. For example, lots of redundant triangles will be generated in the process of generating contour surface. In the meantime, all of the volumes have to be visited. This would have resulted in a low efficiency of algorithm execution.The research on this problem is primarily through two directions:improvements of reconstruction speed and rendering effect. There are two methods to improve the reconstruction speed. One method uses the decimation class which is based on the secondary error metric. The other method is fast MC algorithm which is the combination of the region growing and standard MC algorithm.The experimental results indicate that the two methods both achieve the purpose of improving the reconstruction speed. The first one effectively reduce the number of triangular facets under the condition that the rendering effect can be guaranteed. The second one achieves the purpose by reducing visit of useless volumes. And the rendering result is almost the same as the standard MC algorithm. The result suggests that fast MC algorithm has a higher reconstruction efficiency compared with standard MC algorithm when they are processing the same data amount. In this study, improving the rendering effect by calculating normal and connectivity technology and mesh smoothing also be investigated. After using these three technologies, respectively tissue reconstruction models has been got. |
