【作者】 马晓晨；

【导师】 王太勇；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2009， 博士

【摘要】 工业计算机层析成像技术(Industrial Computerized Tomography),简称工业CT或ICT,是计算机技术与放射学相结合而产生的一门新的成像技术。它利用射线穿过物体发生衰减这一性质,将传感器获得的数据进行重建从而获得被检测物体的三维灰度图像,清晰、准确、直观地反映物体的内部结构、材料密度和缺损状况。工业CT在无损检测(NDT)和无损评价领域得到了广泛运用,成为公认的最佳无损检测手段。三维数据可视化技术不断发展,在诸多行业得到广泛应用。ICT数据的分析及可视化是工业CT检测中的关键性工作。本文研究工作主要集中在以下几个方面:第一,研究了ICT三维数据可视化技术,包括体绘制技术、面可视化技术、轮廓曲面三维重构与可视化。设计了基于二维纹理的ICT快速体绘制算法,对基于层的空间跳跃二维纹理体绘制算法进行了研究,提出了基于区间树的二维纹理体绘制算法,对二叉区间树进行了简化,并应用于体绘制中,大大提高了体绘制速度。第二,提出基于切片分析的交互建模方法,改进了梯度算子的边缘检测算法,应用阈值方法降低噪声影响。在边缘检测的约束下,实现在切片上半自动绘制轮廓曲线,多个切片的轮廓曲线通过插值生成轮廓曲面,从而提高了精度和准确度。第三,研究了ICT三维数据体可视化中的快速算法及渲染技术,主要包括轮廓曲面追踪快速算法、二维和三维图像LOD技术、大型ICT数据的体绘制并行处理技术等,提出了广度八叉树、深度八叉树和深度二叉森林并应用于三维数据场体绘制中,与传统方法进行了比较分析。实验结果表明,此方法提高了渲染效率,将全局和局部体绘制相结合,既提高了绘制速度,又实现了精细观察。第四,研究了弹性波CT的三维可视化和以及相干体数据分析技术并在震波CT数据上进行了试验和应用。第五,依据上述研究,设计实现了基于微机的ICT数据分析和可视化系统。该系统以VR为可视化平台,改变了该类软件一直依赖于大型机和高端工作站的状况,为今后ICT数据分析和可视化技术的普及推广创造了条件。更多还原

【Abstract】 Industrial Computerized Tomography is a new imaging technology which is combined with computer and radiology. Through the property of attenuation of radiation it rebuild the data got by the sensor to display image in 3D style. This technology can reflect the inner structure, density and defect clearly, exactly and derectly. Industrial Computerized Tomography is applied widely in the field of NDT, which has become the best method of NDT. 3D data visualization technology has been developing rapidly recently, and has been applied in many industries. The analysis and visualization is the key and core of ICT detection.This research focuses on five major aspects:Firstly, the study of ICT data visualization technology, including volume rendering technology, surface visualization technology, three-dimensional reconstruction and visualization were conducted. The thesis proposed a new algorithm of rapid volume rendering of ICT, which is based on 2D texture. The 2D texture volume render algorithm based on layer and space skipping was studied. An algorithm of 2D texture volume render based on interval binary tree was introduced, which simplified the interval binary tree. By putting the algorithm into the application of volume rendering the speed of volume render was higher.Secondly, the thesis put forward an interactive modeling method based on slice analysis. It improved the algorithm of edge detection, which used grads arithmetic operators. To reduce the effect of yawp the threshold method was applied. In the restriction of detected edge the semiautomatic drawing of contour lines was realized. The surface was constructed on the contour lines by the interpolation algorithm. This method improved the veracity and precision.Thirdly, the fast algorithm in ICT data visualization, including surface tracing algorithm, LOD technology, and parallel processing technology were studied. A new oct-tree was defined. Compared with the traditional method, the new LOD algorithm was much faster. The results indicated that the new method can improve the effect of volume rendering. Especially, combining the whole and part volume rendering method, the speed was higher and the observation was more elaborated.Fourthly, the technology of seismic wave CT data visualization and relevance volume algorithm were studied and tested on a seismic wave CT data.Fifthly, based on above study, the thesis designed a data analysis and visualization of ICT based on PCs, which took VR as the platform of visualization. This changed the present state of relying on huge computer and graphics workstation.更多还原