【作者】 许万源；

【导师】 段黎明；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 为了将工业CT(Computed Tomography)技术与快速成型技术直接集成,避免样品的三维CAD建模和STL文件的生成,提高反求效率,实现样品的快速仿形加工。本文对工业CT切片数据直接生成RP(Rapid Prototyping,快速原型)层片数据的方法进行了研究,并开发相关软件实现了RP层片数据格式中CLI(Common Layer Interface)文件的生成。首先,提取工业CT切片图像轮廓数据。采用Canny算子检测边缘;综合运用八邻域轮廓跟踪方法、基于间隙分类的断边连接方法和基于跟踪规则的去噪方法完成了图像的轮廓跟踪、断边连接与去噪,获取工件的内外结构轮廓数据。其次,将轮廓数据转化为CLI格式文件。先对相邻层间各轮廓进行匹配,进而提取轮廓特征点简化轮廓数据,对匹配轮廓上的各特征点进行匹配,依据匹配点对,线性插值出相邻层间轮廓,以满足RP加工精度对层片间距的要求。然后,采用三次B样条曲线对各轮廓的特征点进行曲线拟合,按照加工精度要求以弦逼近弧方法对拟合得到的轮廓曲线进行数据点采样,判断内外轮廓生成CLI文件。最后,在本文研究方法的基础上,初步设计开发了工业CT切片数据直接生成RP层片数据的软件。本文对汽车轮廓和茶壶的工业CT切片图像进行处理获取其CLI文件,在AFS-320YS成型机系统软件ARPS2004上查看它们的CLI文件,并对茶壶CLI文件进行快速原型加工,结果验证了本方法的正确性。更多还原

【Abstract】 In order to integrate industrial computed tomography (CT) and rapid prototype (RP) directly, a method of generating rapid prototype (RP) slice data directly from industrial CT images is proposed in this paper. The method can avoid to generate three dimension CAD modeling and STL files of sample workpieces, improve the efficiency of rapid reverse process and realize profile modeling machining. A soft system is developed, which can output common layer interface (CLI) files (one of format of RP slice data) from industrial CT images.Firstly, the contour data of CT image is extracted. Canny algorithm is adopted to check the edge. In order to get the contour data of workpieces, contour tracking based on eight neighbor field method, discontinuous edge joining based on gap classification and de-noising method based on tracing rules were applied.Secondly, the contour point data was transformed into CLI file. By maching the contour of adjacent layer and extracting feature points of contours, the contour data is simplified. Followed by mathing each feature point of the contour, interpolation of contours between adjacent layers is done to shorten interlayer distance of RP slice, which will meet the accuracy requirement of RP. Then cubic b-spline was applied to fit feature point of each contour. Each fitting contour was divided into numbers of short lines under reqired accuracy. Coordinate of the line endpoint can be used to generate CLI file afer judging internal and external contour.Finally, a soft based on the method mentioned above is designed and developed to generate CLI file directly from industrial CT scanned images.An automobile wheel and a teapot are used as examples in this paper. The CLI files output by the developed soft are checked in ARPS2004, which is the system soft of AFS-320YS RP machine. A RP product of the teapot is obtained by AFS-320YS using its CLI file. The validity of the mothed is verified by results.更多还原