激光散斑传感技术具有结构简单、灵敏度高等特点,可以实现对应力、振动、距离、速度、流速等物理量的传感测量,已成为光学传感领域中的研究热点之一。设计了一套基于激光散斑的应力传感系统。该系统使用波长为405 nm激光作为光源,利用音圈电机振动多模光纤,同时采用CCD图像传感采集系统对抛光玻璃表面进行显微成像,通过MATLAB软件对采集到的散斑图像进行分析处理,计算散斑对比度,拟合散斑对比度随时间变化的曲线。结果表明:散斑图像对比度的变化反应了多模光纤应力的变化,通过多模光纤应力变化可以判断是否有入侵者,实现了防盗功能。
The sensing technology based on laser speckle has become one of research hotspots in the field of optical sensing to measure the stress, vibration, distance, speed and flow rate, owing to its significant advantages in simplicity and high precision. A set of stress sensing system based on laser speckle was designed in this paper. The wavelength of 405 nm laser was used as the light source in the system. The voice coil motor was used to vibrate multimode fiber, and CCD image sensor acquisition system was applied to image for polishing glass surface. MATLAB software was used to amdyze the collected speckle images, calculating the contrast, fitting the curve of the speckle contrast. The results show that speckle contrast changes reflect the stress variation in the multimode fiber. Through the multimode fiber stress changes can be judged whether there is an intruder, anti-theft function is realized.