基于生物组织表面特性的体绘制光照模型

传统的光照模型侧重于模拟光能在微面元上的分布，它将表面反射分为镜面反射和漫反射，并采用表面法向与入射光夹角的余弦来模拟漫反射。由于生物组织表面富含水份，因此具有确定性介质和随机介质的双重特性。从物组织表面的漫反射光，就是由于光线射入介质表面产在介质内部被散射，而后射出表面的光能。因此，淡了逼真地表面生物组织的表面特性，必须同时考虑生物介质的表面反射和介质内部体散射双重特性。文中根据生物组织的特点，

AN OPTICAL MODEL OF VOLUME RENDERING BASED ON FEATURES OF BIOLOGICAL SURFACE

The traditional illumination model divides the reflection of a surface into two parts: specular term and diffuse term. The diffuse term is calculated by the Lambert cosine law. As the biological tissues are full of water, they not only have features of deterministic media but also have features of random media. In order to simulate the biomedical surface realistically. Its surface reflection and scattering of the incident light should be taken into account. An attempt is made to calculate the diffuse reflection by solving the transport equation under the single scattering case. The details of volume data are regarded as the texture and both the anisotropic scattering and specular reflection are accounted for. Satisfactory result is shown at the end of the paper.