一种分析薄膜振动模式的结构光条纹时间平均法

Vibration Mode Analysis of Membrane Using Structured Illumination Time-Average Fringe Method

提出了一种用于振动物体表面快速测量的光学测试系统和方法。该系统采用结构光三维传感技术,利用时间平均法来实现对振动表面的测量和振动模式分析。用低帧频商用CCD相机记录由光栅投影到振动物体表面上形成的一系列变形正弦条纹,对获取的一帧变形条纹经过二维傅里叶变换、频谱滤波、逆傅里叶变换等处理得到调制物体振幅的零级贝塞尔函数分布。给出了该方法的理论分析,推导了相应的计算公式。计算机模拟和实验验证了该方法的可行性。实验证明,该方法具有数据获取速度快,全场非接触测量以及实验装置简单等优点。

A new optical vibration measurement method of object surface using structured illumination time-average fringe is presented. Based on the structured illumination three-dimensional （3D） sensing techniques and time-average method, the system realizes the vibration measurement of object surface and vibration mode analysis. A sequence of the deformed and partly blurred sinusoidal fringe images on the surface of a vibrating object are grabbed by a low sampling rate commercial CCD camera. By 2D Fourier transform, filtering, inverse Fourier transform, the zero order Bessel function modulation of the vibration amplitude is obtained. The theoretical analysis and formula of this paper are given. Computer simulations and experiments prove its validity. Experimental results show that this approach has the features of rapid speed, full field and non-contact measurement, and simple experimental set-up.