光学学报, 2015, 35(6): 0612002, 网络出版: 2015-06-01

瞬态形变的高速时域散斑干涉测量

Measurement of Transient Deformation Using High-Speed Temporal Speckle Pattern Interferometry
作者单位

1天津大学精密仪器与光电子工程学院光电信息技术教育部重点实验室, 天津 300072

2天津津航技术物理研究所, 天津 300308

摘要
在迈克耳孙式干涉光路的基础上结合高速摄像和采集系统,利用时域散斑干涉测量技术,实现了瞬态三维形变场的实时测量。物体发生形变时会产生一个时变的散斑干涉场,通过连续采集的散斑干涉图序列便可得到各个像素点的一维时域干涉信号,即光强随时间的变化关系。在利用经验模态分解对干涉信号进行降噪处理之后,借助于希尔伯特变换的相移作用完成信号相位的解调,并在时域中进行相位展开,最终通过逐点分析获得全场的相位分布。为了验证该方法的有效性,对由压电陶瓷驱动的瞬态离面形变进行了测量。结果表明,该方法可在1000 frame/s 的采集速度下实现动态形变的实时测量。与传统相移法相比,该方法结构简单,易于实现,在时间和空间上都具有较高的分辨率。
Abstract
Based on the Michelson-type interferometer combined with a high-speed imaging system, the whole-field transient deformation is measured in real time by using temporal speckle pattern interferometry. With the continuous movement or deformation of the object under study, a sequence of speckle patterns is recorded to acquire the temporal signal of interference intensity at each pixel of the image sensor. The wrapped phase information is extracted by Hilbert transform method, which is regarded as a phase shifter of 90° , and the phase unwrapping is subsequently performed in time domain. Finally, the two-dimensional deformation field is acquired by evaluating the phase information pixel by pixel. To verify the proposed approach, the out-of-plane deformation of the object impacted by a piezoelectric ceramic transducer is measured. The experimental results demonstrate that the transient deformation can be measured by this method under the capturing rate of 1000 frame/s. Comparing with the conventional phase shifting electronic speckle pattern interferometry, the proposed method does not only yield simple implementation, but also has a relatively high spatio-temporal resolution.
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