Study On3D Visualization Technology Of Industrial Image Based On VTK

3D visualization technology of industrial CT image is a very important part of computervisualization techniques and is widely used in the field of nondestructive testing. Thetechnology uses image processing technology and computer graphics, can achieve3D displayof the industrial CT image sequence on the computer after relevant calculation, and also canrealize some operate like each angle cutting of the workpiece and the observation of theworkpiece profile.Firstly, this paper offers a detailed research about preprocessing technology for industrialimages, which mainly consists of the filter and the image segmentation operation forindustrial image series. By the early pretreatment, the next3D visualization is well prepared.In the end, the median filter algorithm is selected to filter image, because it can protect theimage details very well and can eliminate noise largely. In the selection of segmentationalgorithms, edge detection algorithm based on multiple morphological structure elements isused, because the detected edge has good noise résistance, clearer outline, no breakpoint, andfinished preprocessing work well.Then this paper introduces the method of surface rendering and volume rendering for3Dvisualization of industrial image, compares the advantages and disadvantages of two methods.The realization and principle of traditional Ray Casting are explained. Aim at the hugememory consumption and slow rendering velocity of traditional Ray Casting algorithm, thispaper give up the method of skipping the empty voxels in Ray Casting volume renderingprocess, which used in other papers. This paper chooses to split the original data field ofindustrial CT image in the image preprocessing process. Then the original data field will bedivided into the target data sets and the background data sets, and only the target data sets will be carried out volume rendering. This algorithm reduces reconstruction data and greatlyaccelerates the speed of ray casting and interaction.Based on VTK (visualization toolkit) implementation mechanism and the Visual Studio2008platform, Marching Cubes, Ray Casting improved algorithm and Three-dimensionalTexture Mapping algorithm are respectively adopted to visualize the3D image for theindustrial CT image sequence of BMP format. The key procedures and3D visualizationresults are given in the paper. The interactive operations, such as rotation, room and virtualcutting can be realized by user interacts with PC.