关键词: 光线投射, 三维表面模型重建, CT图像, 体素, 阈值

Abstract: In many medical imaging modalities, such as CT, MRI or PET, a 3D anatomy is usually represented by a set of planar images. For its 3D visualization, a voxel model with a ray casting algorithm was introduced. Unlike the triangle method, this algorithm does not require a detection of the boundary of the 3D object beforehand, but derives the surface image directly from the object. The algorithm includes the capability of performing ray castings for different screen pixels concurrently. The concurrent capability facilitates hardware implementation to speed up the surface rendering. The function was given to rotate and to zoom the 3D object in object coordinates and show the result in screen coordinates. Some examples of the depth shading, Gouraud shading, the combination of the depth shading and Gouraud shading, 2D image map to 3D image were shown by using simple threshold segmentation.