Perea James, Libbey Brad
Opt Express. 2016 Apr 18;24(8):8253-65. doi: 10.1364/OE.24.008253.
A laboratory system has demonstrated the measurement of three degrees of vibrational freedom simultaneously through heterodyne speckle imaging. The random interference pattern generated by the illumination of a rough surface with coherent light can be exploited to extract information about the surface motion. The optical speckle pattern is heterodyne mixed with a coherent reference. The recorded optical data is then processed to extract three dimensions of surface motion. Axial velocity is measured by demodulating the received time-varying intensity of high amplitude pixels. Tilt, a gradient of surface displacement, is calculated by measuring speckle translation following extraction of the speckle pattern from the mixed signal. This paper discusses the laboratory sensor concept, signal processing, and experimental results compared with numeric simulations.
一种实验室系统已通过外差散斑成像展示了同时测量三个振动自由度的能力。用相干光照射粗糙表面产生的随机干涉图样可用于提取有关表面运动的信息。光学散斑图样与相干参考光进行外差混合。然后对记录的光学数据进行处理，以提取表面运动的三个维度。通过解调接收的高幅度像素随时间变化的强度来测量轴向速度。倾斜度是表面位移的梯度，通过从混合信号中提取散斑图样后测量散斑平移来计算。本文讨论了实验室传感器概念、信号处理以及与数值模拟相比的实验结果。
