双曝光数字全息三维变形测试

Three-dimensional deformation measurement based on double exposure digital holographic technology

全息三维变形测试在军事、工业测试中有重要意义,而传统的全息术由于记录、显影、定影、再现、复位等条件使其应用受到限制。文中应用CCD实现了数字全息,不仅避免了传统全息显影、定影等过程,也避免了全息材料非线性记录等缺点,并基于双曝光全息干涉术和四步相移法原理,实现了数字相移,取代了传统的应用压电位移器等机械相移法,实现了物体的三维变形测试。由物体变形的二维等高线图和三维立体图,可判读物体变形的大小、变形的方向和变形的形状。大量的实验表明,该方法不仅简化了全息干涉测试的光学装置,而且具有操作简单,测试精度高,其精度容易达到1/10波长。

Holographic three-dimensional deformation test has important significance in the military, industrial test, however its applications are limited because of the requirements of traditional holographic recording, development, fixing, reconstruction and home position. In this paper, applying the charge-coupled device（CCD） digital holography was realized. It avoided not only the developing, fixing processes of traditional hologram recording material, but also the shortcoming of nonlinear recording of holographic material. Based on double exposure holographic interferometry and four-step phase shift method principle the digital phase shift was achieved, replaced the traditional mechanical phase shift method with piezoelectric translator, and the 3D deformation of an object was tested. From the 2D contour map and 3D plot of object deformation, the size, shape, and deformation direction of the deformed object could be interpreted. A lot of experiment results show that these method can not only simplify the optical layout of holographic interference testing, but also easy operate and increase measure precision. The precision can be up to 1/10 wavelength.