| The main content of 3D reconstruction includes medical image pretreatment, image segmentation of tissue, isosurface rendering and direct volume rendering. This paper consists of four parts. The first part concerns in the application and key technology of 3D reconstruction of medical image. The next part of paper concerns in some kinds of technologies of image processing, then, an improved algorithm about image segmentation is contrived, which is based on 2D gray histogram. In the last part, the visualization toolkit is introduced which is the key technique to realize the visualization, then isosurface rendering and direct volume rendering are realized, analyzed and compared.The methods of filtering on image are including the average filtering, median filtering etc. In this paper, the average filtering, median filtering and improved median filtering are discussed mostly. Then the results of filtering on medical CT image are analyzed.The methods of image segmentation are including method based on image threshold, method based on edge detecting and method based on region expansion. The cutting apart approach for image threshold is discussed mostly in this paper. The spatial information can not be represented in normal gray histogram. So the result of segmentation will be awful because of the yawp. This problem is solved in 2D gray histogram partially, but the error is existent all the same, and the time of calculate become much long-playing. In this paper, a new improved algorithm is contrived which can clear up the error and reduce the tine of calculate more effectively. Then the results of segmentation on medical CT image prove the improved algorithm is the best.Finally, Marching Cubes algorithm and Ray Casting algorithm are introduced and analyzed principally, including their elements, bug, solution, etc. The results of the experiment by using VTK, which are done on the head data of medical CT images, show that vivid 3D images can be attained by these algorithms. |
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