數位影像量測於結構實驗之應用

Application of Digital Image Measurements in Structural Experiments

陳北亭(Bei-Ting Chen)

指導教授 ： 黃仲偉

中原大學/工學院/土木工程研究所/碩士(2009年)

https://doi.org/10.6840/cycu200901198

摘要

隨著數位攝影科技的進步與普及，利用數位影像於結構實驗量測的可行性隨之大幅提升。特別是對於大範圍與大變形的實尺寸結構實驗，傳統的應變計與位移計常受到一些限制，而無法完整得到所要的數據，此時可透過影像量測協助提供所需的實驗數據。所謂的數位影像量測係根據物體在變化前、後兩張影像間的相對位置分析物體表面的空間資訊，進而推算出位移場、應變場、裂縫位置等工程上相關的資訊。
本研究之目的即在於自行開發雙相機影像量測與分析系統所需的軟體分析程式與組合硬體設備。此系統的特色在於可提供即時量測，利用雙數位相機即時拍攝實驗影像之後，再進行後續數據的處理與分析。其次，由於具備影像重建的功能，故雙相機之視角不需相同，且適用於不同型號之相機或相機與待測物不等距離拍攝之量測。最後，本系統亦可適用於曲面待測物的量測，不侷限於平面量測。
本文利用零應變實驗與混凝土圓柱試體抗壓實驗進行驗證，實例顯示本文之雙相機系統在位移量測是具有足夠的精確度。最後將此系統實際應用於三維空間之大型結構實驗的即時量測，影像分析可顯示出鋼筋混凝土牆在循環載重作用下的裂縫生成，以及同心斜撐在側力作用下的面外運動。

關鍵字

曲面量測 ； 即時量測 ； 實尺寸結構實驗 ； 雙相機系統 ； 影像重建 ； 數位影像量測

並列摘要

In the past few years, the rapid improvement and popularization of digital camera technology have greatly facilitated the applications of digital image measurement. For the measurements of the large deformation in full-scale structural experiments, which conventional strain gages and displacement sensors have performance limitations, advanced digital image technology especially can help to obtain complete set of information. Through the spatial information analysis on the surface image of an object taken in two different angles, related data such as displacement fields, strain fields, and crack positions et al. can be derived.
The aim of this research is to develop an in-house analyzing software and its corresponding equipment for dual-camera digital image measurement system. The first feature of this system is its capability of providing simultaneous shots for real time measurement. In addition, the image reconstruction method in the developed system can overcome the problem of pattern recognition for dual-camera with different view angles. Different types of cameras and unequal distances between cameras and the object can be treated successfully. Finally, the developed system works well not only for objects with plane surfaces but also graphic surfaces,.
The developed system is verified by the experiments of zero-strain and the compression test of a concrete cylinder. Experimental results demonstrate that the measurement of displacement of this system is accurate enough. Finally, the system is applied in three-dimensional large-scale structural experiments. Experimental images can show the initiation and propagation of the crack of a post-tensioned RC-wall under cyclic loadings and also the out-of-plane motion of an concentric steel braced frame under lateral loadings.

並列關鍵字

two cameras system ； full-scale structural experiment ； image re-construction ； digital image measurement ； real time measurement

參考文獻

23. 林高輝，2000，映射函數三維空間影像量測技術研究，中原大學機械工程學系博士論文。

2. Bowden, R., Mitchell, T. A., and Sarhadi, M., 2000, 」Non-linear statistical models for the 3D reconstruction of human pose and motion from monocular image sequences」, Image And Vision Computing. Vol. 18, No. 9, pp. 729-737.

3. Chang, M. and Tai, W. C., 1995, 「360-deg profile noncontact measurement using a neural network,」 Optical Engineering, Vol. 34, Vol. 12, pp. 3572-3576.

5. Chu, T. C., Ranson, W. F., Sutton, M. A., and Peters, W. H., 1985, 「Application of digital-image-correlation techniques to experimental mechanics」, Experimental Mechanics, Vol. 25, No. 3, pp. 232-244.

6. Cook, R. D., Malkus, D. S., Plesha, M. E., and Witt, R. J., 2002, Concepts and applications of finite element analysis, 4th ed., John Wiley & Sons, New York.