Research On 3D Visualization Algorithm Of Medical Image

3D reconstruction from medical images is a multi-disciplinary subject, which is an important application of computer graphics and image processing in biomedicine engineering. It relates to the subjects of digital image processing, computer graphics and some related knowledge of medical. It can process 3D Volume Data which comes from 2D digital tomographic images, and transform the medical imaging data to 3D graphics and images, which can be displayed on computer screen, by means of computer technology and human vision. This technology can provide more useful visualization information for clinicians, which not only important to theory research, but also valuable and helpful for clinic diagnosing and so on. It is one of the most important hotspots in the current medical imaging research.There are two different approaches of 3D reconstruction from medical images, including surface rendering and volume rendering. Firstly, the thesis briefly introduces several typical methods of surface rendering algorithm and volume rendering algorithm, and analyse their advantages and disadvantages. Compared with surface rendering in 3D reconstruction, volume rendering can concentrate on visualizing internal features of choice and surfaces at the same time. Volume rendering is the emphasis of this thesis.Secondly, this thesis systematically analyses the classical algorithm in the volume rendering algorithm——ray casting algorithm, deeply researches whose basic principle and key techniques such as classification, distributing color and opacity value to each voxel, Phong illumination model, depth modulation, resampling and trilinear interpolation, space transform, projection transform, composition etc. The ray casting algorithm is the most accurate volume rendering algorithm with high computational complexity. Refer to the disadvantage of ray casting algorithm, two accelerating algorithms are presented in this thesis, in order to reduce the the number of ray casted. One of the algorithms calculate the Bounding Volume and projection, the other combine adaptive method with pixel data relativity. Furthermore, quaternion is applied in rotation in place of matrix methods, which can accelerate the processing speed.At last, an interactive medical 3D-reconstruction system is designed by VC++6.0. The system can implement basic function of 3D reconstruction, validate the correctness and high efficiency of the algorithms, and obtain the anticipate results.