频域滤波及相移技术在ESPI中的应用

Application of Fourier Algorithm and Phase Shifting Method in ESPI

本文针对电子散斑条纹颗粒性强这一特点,采用频域同态滤波技术,对ESPI 条纹进行了滤波处理,实验表明,该方法对改善 ESPI 条纹质量非常有效.另外,本文还推出了一种自行设计的新型相移器,它结构简单,操作简便,并且稳定性好,可适用于各种光力学干涉光路.文章最后使用双光束电子散斑法,应用以上技术,对一个带方孔板的平面应力模型的面内位移进行了定量分析.

ESPI(Electronic speckle pattern interferometry)has been used to study in—and out—off—plane displacement of an object.In order to get ESPI fringe pattern with holographic quality,a Fourier filtrating algorithm is employed to remove speckle noise and the procedue is included.In addition,a simply constructed and highly stable phase shiftor,which can be easily used,is designed.It can be used for various coherent arrangement in experiments to obtain phase shifted fringe pattern.As an example of these techniques,the measurement of in—plane displacement in a thin plate with rectangle hole is shown in this paper.