Study On Three-dimensional Visualization Of Medical CT Images

3D reconstruction from medical images is a multi-disciplinary subject,which relates to the subjects of digital image processing, computer graphics and some related knowledge of medical. Meanwhile, it is widely used in diagnostic, surgery planning and simulating, plastic and artificial limb surgery, radiotherapy planning, and teaching in anatomy. Study on 3D reconstruction from medical images has important significance on science and worthiness in practical application. The problems which 3D reconstruction faces are the enormous data to process and the complexity of the medical images, so it is very crucial to optimize the 3D reconstruction algorithms, to improve the accuracy of the medical image segmentation and to accelerate the processing speed. The thesis involves the algorithms researched in every step of 3D reconstruction based on CT images. In this thesis, the key theory and method about visualization in scientific computing are described. On the basis of CT equipment and the characteristic of CT images, the pre-process algorithms are introduced including geometry transform and filter. Two kinds of segmentation are discussed based on area and edge. At last, describe both of the algorithms about Marching Cubes and Ray Casting. To the fault and merit of the algorithms, two improved algorithms are presented: (1) To the topography link disaccord, low efficiency of calculation and large amount of triangle strips in the traditional surface rendering algorithms (MC), surface trace algorithm is presented. It includes surface trace of single lay, data buffer and generation of triangle strips. (2) To the mass data and too slow rate in Ray Casting algorithms, the thesis introduces the algorithms based on segmentation. Via the threshold value algorithms, the data which used in Ray Casting has been lessened greatly. On the PC of the Windows Operation system, the system of 3D reconstruction has been designed by Visual C++ programming language. It includes 3D data import, display of the original and pre-process CT images, acquirement of the data showed vividly on the screen by the improved algorithms about MC and Ray Casting and mutual observation through magnification or demagnification and circumvolving. This system can be the software station for the future research. Possible extension and new directions of the research is also given in the thesis.