摘 要
隨著CAD/CAM/CAPP一體化技術的發展，要求幾何模型能夠表示包含體現產品設計意圖和功能的高層次的工程信息，因而出現了同時面向設計過程和制造過程，包含產品工程信息的幾何造型方法，即特征造型(Feature Modeling)。隨著特征造型技術在機械領域中的應用越來越廣泛,對于反求工程也提出了對于特征提取的要求.本論文提出在反求工程中點云數據拉伸曲面特征提取的一種方法.首先,估算點云的主曲率和主方向,計算最小主方向的平均方向;利用去除含有與最小主方向平均值相差最大的點的方法進行噪聲處理,在此的基礎上得到曲面的拉伸方向;上述是得到拉伸方向的原理,我們可以利用計算機技術實現.把三標機測量機對實物測量所得的數據通過IGES的格式輸入到編譯的REFIT程序,實現計算機與軟件的通信.在REFIT軟件中在拾取點云之后,通過以上的算法,提取拉伸的方向.REFIT軟件是以Microsoft Visual C++ 6.0為編譯平臺,實現的語言是C++.
關鍵詞:反求工程,特征造型,曲面特征,拉伸方向
Abstract
Since cad/cam/capp develop close-coupled, the mold is required for the fuction which can express the products design purpose.then there comes a new method to design model,it turns in the direction of design process and making process.this is named Feature Modeling. This paper gives out one method to get the feature of the extruding surface of the point cloud. First at all, estimate the average value of the main curvature and the main direction; then, calculate the average value of the min direction of every point of the point cloud . Do the filtration which kicks out those points have long distance to the average value of the min direction. On the basis of last step program can get initial direction of the extruding surface. All the words above are discussing the theory , and now that can use the computer to move the theory to the reality. The data which is measured from Three Coordinate Measuring Machine transforms to the format of IGES . then guide into the program named refit . It finishes the communication between the software refit and computer. The program finishes three steps ,the first is getting data, the second is reaching arithmetic , the third is getting the result. By the way ,refit uses Microsoft Visual C++ 6.0 as the platform and the computer language is c++.
keywords: Reverse Engineering , Feature Modeling ,the feature of the extruding surface ,the direction to extrude ,
