光學相位重建於平板振動之應用

The Application of Optical Phase Unwrapping on a Vibrating Plate

陳家豐(Jia-Feng Chen)

指導教授 ： 陳國在

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.10604

摘要

光學量測技術擁有高精密度和非接觸式的優點，並可應用於快速檢測的系統上，故本文利用此優點和延續本實驗室張淑華博士之研究，進行光學相位重建對於平板振動模態應用之研究，並確認光學相位重建之準確度。

本文使用共光路之橫向剪切干涉術，共光路架構可減低環境干擾之影響，在得到干涉條紋圖後，配合相移干涉術和平行性2π相位重建法還原平板振動模態的正確分佈，以期達到只須經由實驗而不需經由軟體模擬即可求出整場的模態趨勢。為了得到較佳的重建模態，故本文加入數位影像處理之技術，利用強度轉換得到光分佈較平均之干涉條紋圖，和使用傅立葉轉換濾波得到較平滑的模態重建圖，並針對平行性2π相位重建法之遮罩進行改良，比較其收斂型遮罩和發散型遮罩在不同雜訊下重建的狀況，其中又以收斂型遮罩對邊界雜訊的處理效果良好。

近年來台灣光學產業發展快速，本文之研究，期待可使本實驗室之光學量測系統，更加趨於完備，建立起快速且高準確度之光學量測系統。

關鍵字

橫向剪切干涉術 ； 光學相位重建 ； 相移干涉術

並列摘要

The optical measurement has the merits of high-resolution and non-contact, and can also be applied to the system of fast-inspection. Therefore, this study uses the above advantages to continue the research about the earlier study of Dr. Shu-Hua Chang in the acoustic laboratory. We make the study in progress on the application of optical phase unwrapping to the vibrational mode on plates, and further confirm its precision.
To greatly reduce the influence by the interference from environment, the lateral shearing interferometry of common optical path is used for this study. After getting interferometric fringe patterns, phase shifting interferometry and parallel 2π phase unwrapping are used to reconstruct the correct shapes of vibrational mode on plate in order to obtain the full-field mode shapes without the simulation of software. In order to obtain a better reconstruction of mode, the technique of digital image processing is used in this paper. Using the transformation of intensity can obtain the interferometric fringe patterns with much uniform light distribut and using Fourier transform filter to obtain more smooth image of reconstructed mode. Furthemore, it is to improve the mask of parallel 2π phase unwrapping for the convergent mask and the divergent mask, and to make comparison between them for various noises.
Recently, industry in optics grows fastly in Taiwan. It is to be expected that the study of this paper can make the system of optical measurement in the acoustic laboratory to become more complete with quickly picking up characteristics and high-accuracy.

並列關鍵字

Lateral Shearing Interferometry ； Optical Phase Unwrapping ； Phase Shifting Interferometry

參考文獻

14. 張淑華，光學干涉術對於平板之動態分析的應用，國立台灣大學工程科學及海洋工程學系，博士學位論文，2007。

1. M.Y.R.K Murty, “The Use of a Single Plave Parallel Plate as a Laterial Shearing Interferometer with a Visble Gas Laser Sour- ce,” Appl.Opt., Vol.3(4), pp.531-534, 1964.

4. H.H.Lee,J.H.You and S.H.Park “Phase-shifting Lateral Shearing Interferometer with Two Pairs of Wedge Plates,” Optics Lett, Vol.28, pp.22-43, 2003.

5. J.B.Song,Y.W.Lee.I.W.Lee and Y.H.Lee “Simple Phase-shifting Method in a Wedge-plate Lateral Shearing Interferometer,” Appl.Opt., Vol.43(20), pp.398-3992, 2004.

6. H.Kadono,H.Takei and S.Toyooka, “A Nosie-Immune Method of Phase Unwrapping in Speckle Interferometry,” Optics and Laser in Engineering, Vol.26, pp.151-164, 1997.