Research On Hybrid Volume Rendering Based On GPU

In recent years, through the joint efforts of many scholars and experts, 3D data visualization has been greatly developed, 3D data visualization is refers to the use of computer graphics and image processing technology, data processing and display to the computer screen a visualization method for user. The most typical techniques of 3D data visualization are volume rendering and surface rendering techniques. Three dimensional space attribute interpolation algorithm and Ray Casting Algorithm are introduced in this paper.In volume rendering using data are generally through the grid data, but the user just start to get the data are discrete, irregular. Therefore, this paper introduces the two kinds of interpolation algorithm, inverse distance weighted interpolation and B-spline interpolation algorithm, the irregular data interpolation encryption into the rules of distribution of the data, and put forward the hierarchical B-spline interpolation algorithm based on B spline interpolation algorithm.Ray Casting Algorithm is a typical volume rendering technology, although the use of this algorithm has many advantages, in dealing with large-scale data still appeared to be inadequate, will appear rendering time is too long, can not be real-time volume rendering. To solve this problem, a Ray Casting Algorithm based on GPU is adopted. In the use of light projection algorithm to calculate the color of each pixel of the screen can be used to calculate the GPU and the parallel processing functions to carry out tedious and repetitive calculations and operations, to solve the problem can not be real-time rendering. But in the 3D modeling process, more is not a separate body rendering volume data, but will need to draw the OpenGL primitives and data on the same screen display are compared and analyzed, but based on direct volume rendering techniques for the GPU, OpenGL primitives and number according to the body with the screen will display the mutual occlusion of the problems. This can use based on GPU hybrid volume rendering algorithm to solve this problem. The basic idea is to OpenGL primitives and data pattern for hybrid volume rendering process using OpenGL technology of basic primitives for two rendering, first draw the depth and color information of OpenGL primitives drawn to the frame buffer; the second drawing is according to the will of OpenGL primitives and 3D data graphics and rendering, the OpenGL primitives and volume rendering volume data fusion of the right drawing the frame buffer depth and color information, based on a mixture of GPU rendering technology to achieve the volume rendering and surface rendering the organic combination of, for the body drawing application technology in 3D interaction and explaining the modelling to lay the foundation.