为解决医学图象三维可视化中三维体数据显示的问题,在综合了体绘制源-衰减模型和兰伯特漫反射余弦定律的基础上,提出了体绘制源和反射-衰减光照模型.新的模型假定三维标量数据场中的每一点都既是点光源,又能够反射外部入射光,并且反射光的分布遵循兰伯特漫反射余弦定律.由以上假定推导出体绘制的基本运算公式.实验结果表明,体绘制源和反射-衰减模型是一种性能优良的体光照模型,其用于医学断层图象三维可视化能够生成逼真的显示图象.

For almost all kinds of medical images, especially image series generated by CT, MRI and B-Scan, the difficulty consisting in the rendering of three-dimensional (3D) volume data set is actually a key hindrance for 3D Visualization. Aiming at the problem, a lot of models and algorithms have been proposed. In medical imaging, shortly after the publication of“Volume Rendering”written by Dr. Drebin, the algorithm of volume rendering based on classification became very popular. However, the common method can be only a makeshift. 3D visualization, in terms of direct insight into the volume data set, should not be the superstructure of classification, but the basis of it. Summarizing the Source-Attenuation model of volume rendering and Lambert Cosine Law of diffuse reflection, in the paper, a new light model of Source &Reflection-Attenuation for 3D Visualization in Medical Imaging is proposed. This model assumes that each point in the three-dimensional scalar data field is a light source and can also reflect the incident ray, moreover the distributing of reflected light conforms to Lambert Cosine Law of diffuse reflection. The experimental results show that the new model can produce vivid 3D images, when used for 3D visualization in medical imaging.