一种新型动态三维外差散斑干涉测量技术的研究

Electronic speckle pattern interferometry (ESPI) is a well established technique for measuring out-of-plane and in-plane displacement components, strains, slopes, curvatures, and vibrations of a diffusely scattering object. Thus, it is widely used in measurement for academic and industrial research, and inspection in areas such as experimental mechanics, vibrations analysis, and nondestructive evaluation. However, the traditional measurement of displacement needs two statues: before and after deformation. Hence temporal and continual deformation can not be measured. In addition, the measurement range of deformation is relatively small. Therefore a temporal speckle pattern interferometry (TSPI) was presented，which can obtain the whole-object deformation by using Fourier transform methods of the speckle pattern recorded in a sequence while the object is being deformed. To further expand the measuring range and to improve the anti-interference ability, heterodyne temporal speckle pattern interferometry (HTSPI) was presented, in which the carrier frequency was introduced. But there are still several problems existing, for example, there are rotating parts in HTPSI, which has seriously affected the measuring accuracy; The measuring range still needs to be expanded as well; There are no HTSPI which can measure 3D displacement of object,etc. To solve these problems, the new method to introduce the carrier frequency is presented in this application. Meanwhile, the multiwavelegth measuring technique is introduced in this HTSPI, which expands the measuring range effectively. Furthermore, a new HTSPI device which can measure 3D displacement of object dynamically will be built, It can be applied in the measuring of displacement,strain,nondestructive testing,vibration,etc.

)：由于散斑测量技术中最常用的时间相移法存在不能测量动态位移、测量范围小、不是真正意义上的实时测量、需要一套昂贵的PZT 设备等缺点，2000 年以来国际上提出了外差时域散斑测量技术。这种技术具有结构简单、测量范围大、可以测量动态变形、抗干扰能力强等优点，因而有着越来越广泛的应用。但目前这种技术尚存有缺点，具体表现在：外差装置产生部分有旋转部件，对测量精度的影响较大；测量范围仍需扩大；尚无可以同时测量三维形变的该种装置的报道。针对这些问题，本申请采用了新的外差产生方法，克服了原有方法中差频不稳定的缺点；同时，本申请将多波长测量技术引入了时域散斑测量技术中，有效的扩大了测量范围。另外提出了能同时测量物体三维动态变形的外差时域散斑装置的方案。该技术将在物体的位移、应变、无损探伤、振动测量等方面发挥较大作用。

电子散斑干涉（ESPI）技术具有非破坏、高精度、高准确度可进行三维动态测量的特点, 广泛应用于航空、航天、汽车、微电子、国防工业等领域。目前主要的散斑测量仪器还是采用时间相移原理，这种测量方法的主要问题是不能完成实时测量，同时需要一套精密的压电陶瓷驱动装置。针对以上问题，同时考虑到电子散斑测量技术的应用场合多在室外，因此需要测量设备具有较好的抗干扰性能，因此本项目将抗干扰性强的外差技术和时间序列散斑测量技术结合起来，实现了对物体的离面变形外差实时测量；针对目前传统的三维散斑测量需要三套独立测量子系统带来的图像配准问题，采用三个不同波长激光光源结合一个3-CCD彩色相机的方法，简化了结构，实现了物体位移的三维实时测量；另外，本申请还将时间序列散斑测量技术和偏振数字剪切散斑技术结合，解决了物体变形梯度难以实时测量的问题，并完成了原理验证实验。