The Research Of GPU-Based3D Texture Mapping Volume Rendering

Volume rendering is one of the important technology of computer3D visualization.Volume rendering draws out high quality3D images containing a variety of information bythe way of direct treatment and overall synthesis, which is more suitable for people to dooverall and comprehensive observation and analysis for volumetric data. At present, in theplatform of PC volume rendering technology based on CPU is basically competent to dolarge-scale real-time rendering for volumetric data, but for huge-scale volumetric data or onoccasions where frequent interactions are needed, the further promotion of the volumerendering efficiency will be greatly limited by the CPU serial data processing mode.In recent years, with the rapid development of computer graphics hardware, especiallythe breakthrough of GPU (Graphic Processing Unit) technical performance and functionextension which provide a technical way achieved basing on GPU programming for volume.With studying the programmable functional pipeline of GPU (Graphics ProcessingUnit), the classical GPGPU (General Purpose Graphics Processing Units) technique basedon OpenGL texture mapping has been discussed in this paper, and has been applied tovolume rendering of3D texture mapping, to achieve the volume rendering that based on theGPU3D texture mapping. On account of to the shading of the volume rendering, this paperpresents the GPU-based translucent shading algorithm and the GPU-based Phongillumination shading algorithm, respectively, which improved the speed and efficiency ofthe shading for volume rendering. This paper includes following main contents:1. Considering the GPU general-purpose computing technology, the classical GPGPUtechnique based on OpenGL texture mapping has been emphasized, and some commonserial algorithms were employed in a parallel implementation by using this classicaltechnique, of which the parallel advantages have been verified through experimental results.2. The whole process of volume rendering based on3D texture mapping has beenresearched and put into effect. Targeting to the shading of the volume rendering, this paperfocused on discussing the window transformation accelerating algorithm that optimized byCPU and the Phong illumination model accelerating algorithm, and obtained practicalrendering graphics and relevant experimental data of there two accelerating algorithms.3. A volume rendering methods using the GPU3D texture mapping has been analyzedto design as well as to achieve the whole volume rendering process on the basis of3Dtexture mapping. Aiming at the shading parallelism in the volume rendering, the GPU-based translucent shading algorithm and the GPU-based Phong illumination shading algorithmwere proposed, respectively. Using the classical GPGPU technique, volume data andgradients were mapped into texture cache of the graphics card, where multithreadingparallel processing was used in fragment shader to realize window transformation algorithmand Phong illumination algorithm, which significantly improved the speed and efficiency ofthe shading for volume rendering.