为了精确地测量物体表面的动态形变并得到形变高度和梯度信息,提出了一种基于双孔衍射结构的空间载频剪切散斑干涉法.该方法采用双孔产生固定的载频条纹,利用双旋转光楔实现剪切量的连续调节,采用正弦拟合算法进行相位计算.首先,分析了双孔调制的相位载频与双孔距和像距之间的关系,讨论了双旋转光楔得到线性剪切量调整的实验参数.然后,设计了测量光路参数;采用孔距为3.8 mm的双孔径配合焦距为80 mm的成像镜头在物距为300 mm时得到了载频为π/2的散斑场.最后,对动态形变的薄金属板进行了测量.实验结果表明:配合实时图像处理系统,该方法可以在帧率为15 frame/s的采集速度下实现动态形变的测量与显示,可测形变峰值为0.11～1.15 μm.本系统结构简单,易于集成,适用于动态形变的实时检测.%To measure the dynamic deformation and slope of an object surface,this paper proposed a shearing speckle interferometry with a spatial carrier frequency generated by double-apertures.In this method,a double-aperture mask was used to generate a spatial carrier,a rotating wedge pair was utilized to adjust the shear continuously and the sinusoidal-fitting algorithm was taken to calculate the phase distribution.This paper firstly derivated the relationship between the carrier phase and the separation of double apertures and also imaging distance.Then,the experimental condition to generate adjustable lateral shear was discussed based on the ratable wedge pair.Finally,the parameter of this measuring method was analyzed.To produce a π/2 carrier frequency,it suggested that the separation of double aperture was selected as 3.8 mm when the focus length of the imaging lens and object distance were 300 mm and 80 mm,respectively.A stress release plate after centre loading was measured,and the experimental results demonstrate that this measuring system can obtain the information of deformation in real time under the capturing rate of 15 frame/s and the measurable range of displacement peak value is from 0.11 to 1.15μm.This approach yields simple and compact optical implementation and allows a real time detection for dynamic deformation.
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