四步数字相移全息干涉术三维变形测量

Three dimensional deformation measurement with four step digital phase shifting holographic interferometry

针对目前相移控制器件费用高、操作复杂等不足,提出了一种数字相移方法。并将其与全息干涉术相结合,进行了相移全息干涉术的实验研究。应用MATLAB软件,结合图像处理方法,通过对全息干涉条纹精确控制使其定向移动,实现了四步相移,获得4个干涉图。应用四步相移法原理和相位去包裹方法,最终成功求得物体变形引起的三维位相差,实现物体变形的三维测试。实验表明,该方法不仅简化了全息干涉测试的光学装置,避免传统相移器件相移精度低、容易造成相移误差的缺点,且操作简单,测试精度高,其精度容易达到1/10波长。

Aiming at the disadvantages of high cost and complex operation of phase-shifting controller, a digital phase shifting method has been put forward. Combining the method with holographic interferometry, the experiment re- search of phase shifting holographic interferometry has been carried out. Based on MATLAB and image processing, the holographic interference fringes are directionally moved under precise control condition. Then, four step phase shifting method is realized and four intefferograms are obtained. According to the principle of four step phase shifting method and phase unwrapping method, using digital phase shifting method for three times to obtain four interfero- grams, the three dimensional phase difference map of object deformation can be successfully obtained. Three dimen- sional deformation measurement is realized. Experiment results show that the method can not only simplify the optical setup of holographic interference test, but also avoid the disadvantages of the phase shifting error caused by the low precision of phase-shifting controller. Moreover, the method features simple operation and high precision, the preci- sion can easily reach 1/10 wavelength.