数字散斑干涉技术及应用

介绍了数字散斑干涉技术在位移、应变、振动和医学诊断等领域中的应用和国内外发展状况。提出了一种新的应用领域—数字散斑干涉技术在语音识别中的应用,并对该方法作了介绍,讨论了它的特点。     

基于高速摄像的ESPI全场动态特性测量

采用高速摄像与ESPI技术相结合,将运动中的被测物位移随时间变化的状态以序列图像的形式实时记录,并运用图像处理技术,成功地实现了ESPI动态测量。测量了悬臂梁的自由振动过程,获得了悬臂梁的振动周期、振动频率和阻尼系数等动态特性,实验结果与理论计算值相吻合。     

三维物体表面形状检测技术的深入研究

本文对三维检测技术做了简要的介绍,给出了迈克耳逊干涉仪、电子散斑干涉法（ESPI/DSPI）、三角检测法的检测原理,同时对三维轮廓检测技术做了深入的研究。     

激光干涉在蜂窝夹心层板振动模态测量中的应用

采用激光电子散斑干涉测量技术(electronic speckle pattern interferometry,简称ESPI)对悬臂矩形损伤蜂窝夹心复合板稳态振动下的振型进行了实验研究。通过完整试样的振型测量结果与有限元模拟均匀悬臂金属板结构振型的类比,验证了有关蜂窝夹心复合材料具有横观各向同性假设的观点,获得了悬臂矩形蜂窝夹心复合层板前14阶离面振动模态的振型图。实验结果表明,结构的损伤导致其局部刚度改变,使得共振频率减少,损伤对其高阶振型的形状改变较为明显,有时甚至是模态跃迁。     

载频电子散斑位移场分离技术研究

提出了载波调制分离位移场的方法.在双光束电子散斑干涉(ESPI)中增加参考光,使这路参考光为两光束所共用.通过偏转物体引入载波调制条纹,具有条纹对比度高的优点.物体加载后,载波条纹受物体变形的调制而发生弯曲变形.实验时,两束光各自独立地对变形物体进行测量,采集物体变形前后的条纹,利用傅里叶变换法,可分别解调得到包含离面和面内位移信息的2幅位移图.理论分析表明,只需简单的位相运算,就能够将面内位移场与离面位移场分离.利用典型的周边固定、中心加载的圆盘实验,表明了该方法的可行性;周边固定、中心加载的圆盘变形所包含的面内位移大小与离面位移相比,大约低1个数量级.     

基于激光的散斑干涉术及其测量中的应用

对电子散斑干涉技术用于测试离面和面内位移的原理和光路进行了详细阐述,并分析该方法的适用范围和灵敏度,给出了圆盘试件离面位移和金瓷试件面内位移的测试结果。表明基于激光技术的电子散斑干涉法适用于硬质材料位移和无损检测,结果以干涉条纹图形式给出,易于定性和定量分析研究对象位移。     

应用ESPI和实时全息测量轴对称温度场

本文应用电子散斑干涉法(ESPI)和实时全息干涉法,从互相垂直的两个方向,同时测量了酒精灯火焰温度场和喷射(jet impingement)温度场。文中应用交互式高速数字图像处理系统处理了全息和散斑条纹图,并定量计算了剖面上的温度分布。还就可能出现的实验误差进行了分析。     

电子散斑干涉技术的精度研究

通过电子散斑测量离面位移的实验研究,对电子散斑干涉计量的测量精度进行了评估,分析了误差来源并提出了提高该技术测量精度的措施。     

Experimental and numerical investigations for the free vibration of cantilever trapezoidal plates

Abstract

Based on the advantages of non‐contact and full field measurement, the optical technique called amplitude‐fluctuation electronic speckle pattern interferometry (AFESPI) with an out‐of‐plane setup is employed to investigate the free vibration of cantilever trapezoidal plates with various taper ratios and sweep‐back angles. Twenty different plate configurations are analyzed, including triangular and trapezoidal plates, and the first seven vibration modes of each plate are measured. The AF‐ESPI method is very convenient for measuring vibrating objects because no contact is required in contrast to classical modal analysis using accelerometers. Based on the fact that clear fringe patterns will appear only in resonance, both resonant frequencies and corresponding mode shapes can be obtained experimentally using the present technique. Numerical calculations by finite element method are also performed and the results are compared with the experimental measurements. Excellent agreements are obtained for both results of resonant frequencies and mode shapes. The influences of taper ratios and sweep‐back angles on the vibration behavior of cantilever trapezoidal plates are also demonstrated in terms of the dimensionless frequency parameter.     

An electro-optic holography system with real-time arithmetic processing

This paper reports the use of a real-time arithmetic image processor in an electro-optic holography system. A speckle interferometer is used to combine an image of an object, lit by laser light, with a mutually coherent reference beam. A CCD TV camera detects the interference pattern, and the phase of the reference beam is advanced by 90° between frames. An image is generated from each set of four sequential TV frames by subtracting alternate frames, squaring, and adding the two results. The result is improved picture quality compared with the use of binary pixels and compared with electronic speckle pattern interferometry. Experimental results are shown.