Research For Three Dimensional Visualization Technology Based On ICT Data Field

The three-dimensional (3D) visualization technology of industrial computerized tomography (ICT) is a comprehensive technology developed in the base of computer graphics, computer vision and computer image processing. This technology is an important branch of computer visualization technology and plays an important role in non-destructive test (NDT). The 3D visualization technology applies the computer graphics image processing technique to transform the resulting data from the process of scientific computing to graphics and images that will be displayed in computer screen. At the same time, the appearance of 3D visualization technology solved the puzzle that the workpiece inside defect is unable to display with three-dimensions, and can observe the section from any direction. Therefore, this technology is not only important in theory research, but also valuable and helpful for practical application.The key technology of 3D regular data field visualization is discussed in this paper. Firstly, this paper offers a detailed introduction about the relevant content of surface rendering and volume rendering, including the concept, characteristic and the process of rendering. Secondly, this paper describes several typical algorithm of the rendering, and concludes their improvement. And analyze and evaluate their performance, get the effective method of improving the efficiency of the algorithm. Then, based on the content mentioned previously, we get the common idea of rendering speeding according to analyzing the processing of rendering. Finally, this paper adopts a high speed surface rendering algorithm based on marching cubes and a high speed volume rendering algorithm based on ray casting. The disadvantage of Marching Cubes (MC) algorithm is modified and improved in several aspects. A 3D industry imaging surface reconstruction scheme was utilized, which integrates segmentation and Marching Cubes algorithm. The comparability region segmentation method was applied to the image sequence according to the feature of the industry image, then the segmentation result was used as the input of MC to generate equivalence surfaces. At the same time, the asymptotic decider algorithm is employed to solve the ambiguity problem and improved the quality of image.Aim to the problems of powerful computing capacity and slow rendering velocity, a improved algorithm of ICT slice images original data field 2D maximum entropy threshold segmentation prior preprocessing in the course of ray casting volume rendering is utilized. The 2D maximum entropy threshold method is used to define the extent of threshold, and research the optimal combination of the parameters. Then the area threshold removing method is applied to filter the noise. Binary processing of image is done. This algorithm reduced reconstruction volume data and greatly improves the efficiency of ray casting. The speed is improved.