基于MC的医学三维等值面的平滑与归并

Smoothing and Merging of Medical Isosurface Based on MC Algorithm

为了提高医学三维图象的重建效果和速度 ,在对用于构造等值面的 MC( Marching Cubes)算法进行分析的基础上 ,提出了对等值面进行三维空间方向平滑和多边形法向归并的方法 .等值面方向平滑的方法就是将等值面分解为一个三维坐标场和一个法向矢量场 ,然后对其法向矢量场作矢量平滑处理 ;而等值面的多边形法向归并则是根据适当的门限值 ,将原来由大量小三角面片构成的等值面归并成由较少的多边形面片构成的等值面 .实验结果表明 ,该方法能显著改善三维重建的效果 ,并能提高三维绘制的速度 .

Based on the detailed analysis of MC(Marching Cubes)algorithm which is widely used for extracting Iso surface from volume data filed, this paper presents a new method for 3D reconstruction and visualization: directional smooothing and polygonal merging on the extracted iso surface. The directional smoothing method decomposes the Iso surface into a 3D coordinate field and a vector field, and then performs a smoothing process in this vector field. By vector field smoothing, the reconstructed results and the rendred anatomical details are greatly improved. The method of Iso surface merging is analyzed in this paper. According to correct merging principles and threshold value, this method transforms the triangle composed iso surface into polygon composed iso surface, and it can greatly speed up the 3D rendering process without impairing reconstruction fidelity and anatomical details. A modified approach of 3D reconstruction and rendering is presented in this pqper, which can improve the results of 3D reconstruction, and at the same time, speed up the 3D rendering process.