数字散斑剪切干涉及偏转平台法相移系统研究

在传统的剪切电子散斑干涉中 ,直接观测到的是干涉条纹图样。因此 ,如何将位移导数场的定量信息从剪切电子散斑干涉条纹图案中提取出来 ,一直是人们关心的问题。本文运用传播光矢量对数字散斑剪切干涉的条纹形成作了理论解释 ,使其物理意义更加清晰。理论分析表明 ,物体的微小偏转可引入线性附加位相。因此 ,通过连续偏转物体可实现剪切电子散斑干涉的相移。本研究通过计算机控制载物平台的精细旋转实现相移 ,结合传统的数字散斑剪切干涉技术以及四步相移算法 ,实现了数字剪切散斑干涉相移系统。利用该系统进行了中心加载、周边固定的圆盘的典型实验 ,实验结果表明该系统可以方便有效地提取出位移导数场的定量信息。

Study on Digital Speckle-Shearing Interferometry and Rotating Stage Phase-shifting System

Because the speckle fringe patterns are observed readily on a TV monitor in traditional digital speckle-shearing interferometry before it is further developed. How to obtain the information of derivative fields of displacements quantitatively from the fringe patterns has been researched at all time. A new fringe interpretation about digital speckle-shearing interferometry by using propagation vector is presented in this paper. Theoretical analysis shows that a linear additional phase can be introduced by rotating a test object a small angle, by which the phase-shifting technique can be achieved. Thus in this research the load stage controlled by a computer revolves an accurate small angle to introduce phase-shift. Combining traditional digital speckle-shearing interferometry and four-step phase-shift arithmetic, a digital speckle-shearing interferometry system is realized. Using this system a typical experiment with a centrally loaded clamped circular plate is successfully completed. The experimental results show that it is effective to obtain displacement derivative fields quantitatively from fringe patterns of the test object.