逆向工程中以精度為導向之多層級曲面量測及重建研究

The Research of Multi-level Compound Surface Measurment and Reconstructed with Precision-Guide

刁守仁(Shoou-Jen Tiau)

指導教授 ： 李碩仁

元智大學/工程學院/機械工程學系/碩士(1994年)

摘要

由於 CAD/CAM 系統與電腦數值控制式三次元量測儀(CNC type CMM)的整
合，近年來，逆向工程(reverse engineering)已逐漸成為一種重要的工
程技術，在逆向工程中，主要包括有對原始模型(physical parts)之數值
化(digitization)、曲面模型之重建等關鍵技術。本文所探討之逆向工程
，是利用三次元量床以電子觸發式探頭 ( touch-trigger probe ) 對複
合曲面模型 ( compound surface model)作掃瞄量測，然後對量測及數值
化所得之點數據，直接作探頭偏量(offset)補正；再以三次仿樣曲線(
cubic -spline)對量測之點群數據(scatter data)作曲面重建。在本研究
中，是以類四分法 (quadtree-like)之層級及區塊劃分原則，來規劃多層
級之整體量測策略，並依據邊緣圓角之加工精度作為區塊劃分之最小單位
；對於複合曲面，是以零交越法(zero crossing)作邊緣判別(edge
detect)，將複合曲面之邊緣區隔；對於重建曲面之準度，則以插值與量
測值之誤差作為評估指標，對於未達準度指標的區塊則再細分精量，以確
保重建之曲面達到精度規格；最後，將建立以區塊為主之完整曲面模型。
在本文中將以兩個實體模型，一為多斜角模型，另一為半球模型，來驗証
本文所發展之整體量測與數值化策略 (strat- -egy)以及曲面模型重建法
則(algorithem)。

關鍵字

座標量測儀 ； 類四分法 ； 零交越法 ； 邊緣判別 ； 曲面重建

並列摘要

With the integration of CAD/CAM systems and computer controlled
coordinate measuring mechine（CMM） , reverse engneering has
emerged as an important design tool in recent years. The
techniques mainly involve measuring and digitization from
physical parts and surface model reconstruction. In this
thesis, the physical parts was scanned by CNC type coordinate
measuring mechine equipped with a touch- trigger probe. A
correcting procedure for the probe center offset is developed
in this thesis. Then, using the surface model was
reconstructed from measured points data by the cubic-spline
methode. Features of this thesis are: (1)we use the quadtree-
like method to achieve the multi-level measuring strategy.
(2)The zero-crossing method is applied to detect the
characteristic curve of compound suface, then we can found the
boundary (edge)variety sharply. (3) The block is a unit use to
estimate the accuracy of the reconstructed surface achieved by
compare the predict points and check points.If the
reconstructed-error larger than the specific limit,this block
will be redivided and remeasured again, until all blocks reach
the precision requirement. In the end, the entire measurment
strategy, the edge detect result, and the reconstructed cubic-
spline surfaces and its error analysis will be proved by two
examples, one is a multi-slope magnatic set, another is a semi-
sphere set.

並列關鍵字

coordinate measurimg mchine(CMM) ； quadtreelike ； zero crosssing