Fu Yu, Shi Hongjian, Miao Hong
Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore.
Appl Opt. 2009 Apr 10;48(11):1990-7. doi: 10.1364/ao.48.001990.
Measuring deformation of vibrating specimens whose dimensions are in the submillimeter range introduces a number of difficulties using laser interferometry. Normal interferometry is not suitable because of a phase ambiguity problem. In addition, the noise effect is much more serious in the measurement of small objects because a high-magnification lens is used. We present a method for full-field measurement of displacement, velocity, and acceleration of a vibrating miniature object based on image-plane digital holographic microscopy. A miniature cantilever beam is excited by a piezoelectric transducer stage with a sinusoidal configuration. A sequence of digital holograms is captured using a high-speed digital holographic microscope. Windowed Fourier analysis is applied in the spatial and spatiotemporal domains to extract the displacement, velocity and acceleration. The result shows that a combination of image-plane digital holographic microscopy and windowed Fourier analyses can be used to study vibration without encountering a phase ambiguity problem, and one can obtain instantaneous kinematic parameters on each point.
对于尺寸在亚毫米范围内的振动样本，使用激光干涉测量法测量其变形会带来许多困难。由于相位模糊问题，常规干涉测量法并不适用。此外，在小物体测量中噪声影响更为严重，因为使用了高倍放大镜。我们提出了一种基于像面数字全息显微镜的方法，用于对振动微型物体的位移、速度和加速度进行全场测量。一个微型悬臂梁由具有正弦配置的压电换能器台激发。使用高速数字全息显微镜采集一系列数字全息图。在空间和时空域应用加窗傅里叶分析来提取位移、速度和加速度。结果表明，像面数字全息显微镜和加窗傅里叶分析相结合可用于研究振动，而不会遇到相位模糊问题，并且可以在每个点上获得瞬时运动学参数。
