Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/47857
標題: 瞬時多波長數位光彈技術之時間域與空間域相位展開比較研究
Simultaneous Temporal and Spatial Phase Unwrapping of Multiple Wavelength Digital Photoelasticity
作者: 黃敏睿
關鍵字: 機械工程類;技術發展
摘要: 
本計畫擬針對現有較常用的幾種數位光彈相移法則分析其可靠度與強鍵性,並將以Poincare Sphere為工具來分析是否有重新建立更為可靠而穩定的相移法則的可能性。計畫中也擬結合時間域及空間域二種相位展開技術,進行光彈主應力角與主應力差等相位資訊的展開,所發展技術並擬應用於靜態與動態的光彈實驗判讀上。光彈全場量測技術可同時取得受測體上每一點的主應力角與主應力差資訊,而數位光彈更結合多場相移影像,再經由反正切函數計算出主應力角與主應力差相位圖,若結合使用高記憶容量及高運算速度的電腦資料處理能量及高解析彩色數位相機,數位光彈的應用技術變得極為多樣,處理的能力上也大大地提昇。然而,相位圖的相位展開上面臨了主應力角與主應力差間交互作用所造成相位模糊的問題,目前文獻已提出處理模糊區域的方法有負載步階法、多波長法、影像處理判斷方式等時間域及空間域相位展開方式,本計畫中擬針對這些方法進行比較研究與探討,以提出較有效的相位展開方式,計畫擬以模擬的方式進行偏光儀特性的分析,傾向分析並建立以三波長資訊逕進行時間域相位展開技術,與空間域相位展開方式進行優劣比較。最後進行光彈實驗來驗證所提方法的正確性與有效性,並以可瞬時同時取得多場光彈條紋影像的光學架構來進行動態光彈相移影像的擷取,相關光學系統校正調整及多場影像間的相關性處理,計畫中一併探討。

Photoelastic stress analysis is a full-field optical technique for experimental stress analysis whose automation has received considerable research attention over the last two decades. Use of phase shifting has revolutionized the acquisition of photoelastic data. In addition, the availability of powerful computers with large memory capacity and colour, high resolution, cameras has made the digital photoelasticity technique with wide variety. However, there exists a tough problem - isoclinic and isochromatic interaction, which leads to the so-called ambiguous zone in the phase map and makes the unwrapping difficult. Various methodologies have been proposed to solve the ambiguity problems of photoelastic phase maps including load stepping, image processing skills, and different wavelengths etc. Different phase stepping techniques had been proposed for the photoelastic measurement. Among them, the six-step phase shifting technique based on a circular polariscope arrangement is widely accepted and used for its simplicity and accuracy. Plane polariscope, however, is the simplest setup for isoclinic and isochromatic parameters extraction. Elliptical polariscope is used for the minimization of the dispersion of the wave plate under illumination of different wavelengths. The intercomparison between them, including easiness of individual setup, factors that affect quality of map, and noise reduction of calculated phase map, will be analyzed in details in the work. The sequential collection of the phase stepping photoelasticity grams has limited the application to only static analysis. Thus, the work herein will capture in real-time all the information needed to produce full-field maps of isochomatic fringe order and isoclinic angle and deal with the optical alignment of four phase shifted beams and the calibration of simultaneous grabbed images for the correct determination of photoelasticity parameters. Multiple wavelengths isochromatic data are used for the check of whether or not its corresponding isoclinic data is correct. Thus, it is very useful on the isoclinic and isochromatic data retrieval.
URI: http://hdl.handle.net/11455/47857
其他識別: NSC100-2221-E005-019
Appears in Collections:機械工程學系所

Show full item record
 
TAIR Related Article

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.