散亂點資料重建B-spline曲面之研究

Reconstruction of B-spline surace from scattered points

鄭欽元(Chin-Yuan Cheng)

指導教授 ： 尤春風

國立臺灣大學/工學院/機械工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.02880

摘要

電腦輔助設計與製造目前在工業已被廣泛使用，在逆向工程方面，必須將由三次元掃描儀所量測資料建成網格模型，再由網格模型建立為參數曲面。而本研究目的在探討由散亂點資料建立為B-spline曲面之完整過程。處理的問題包含，點資料的網格化、散亂點掃瞄線重建、資料的處理分析與B-spline曲面的重建。

重建網格曲面過程中，將所量測點資料利用分群與網格拓撲關係加速重建過程。而散亂型態的點資料可經由平面分割與網格拓撲關係取點重建其掃瞄線。並在嵌合曲線前，將掃描線之點資料進行取樣、均勻化、平滑化…等前處理程，經由正負號之曲率分析取得代表曲面外形之特徵點。最後以合併所有特徵點之節點值所得之特徵節點，對各掃描線重新取點，用以嵌合B-spline曲線與曲面。

關鍵字

逆向工程 ； 曲面重建 ； 三角網格 ； B-spline ； 散亂點

並列摘要

Computer-aided design(CAD) and computer-aided manufacture(CAM) are extensively used in industry. In reverse engineering, at first we should modeling the point data measured by 3D coordinate measuring machine as the triangular mesh, then reconstruct a surface model from the triangular model. This thesis has a goal to discuss the reconstruction processes from scattered point to surface model, which forms triangulation of data points, reconstructs scan lines from scattered points, pre-processes of data points and surface reconstruction.

In reconstruction process, first of all we accelerate the triangulation of measure data by mesh topology and cluster the data points for several parts. About scattered points we could create scan lines by cutting plane and mesh topology. Then use data reduction, uniform and smooth method for rearranging the data points of all scan lines, and pick the feature points by directed-curvature analysis. Finally merge the knot values of all feature points to create feature knot vector, and use it to select new data points. With the data points, we could get B-spline curves by curve fitting and reconstruction B-spline surface by surface lofting.

並列關鍵字

Reverse engineering ； surface reconstruction ； triangulation ； B-spline ； scattered points

參考文獻

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