用散斑干涉光谱分布检测瞬态温度

为了提高对瞬态温度检测的灵敏度,提出了基于散斑干涉条纹光谱分析的瞬态温度反演算法.系统利用散斑干涉形成干涉条纹,由于瞬态温度的变化会使材料应变,从而使散斑干涉条纹改变.被测表面形变前后获得的干涉条纹由面阵 CCD 采集,其对应的光谱密度分布函数也会发生相应的改变,即由散斑干涉条纹反演得到的中心波长振幅发生改变.通过对两次中心波长幅值的比值的检测和计算,即可获得被测的瞬态温度.在分析计算了瞬态温度变化与材料应变、材料应变与干涉条纹变化的函数关系的基础上,推导了瞬态温度变化与干涉条纹振幅及相位函数关系.实验采用660 nm 半导体激光器,SI6600型面阵 CCD 探测器,从获得的光谱分布函数中提取中心波长处幅值比值,通过计算和标定,最终温度检测精度可达到±2℃.相比传统的直接检测干涉条纹的变化量,由被测面形变量推导温度的方法精度提高了近一个数量级,其精度更高、检测均匀性更好、稳定性更好.

Test of Transient Temperature for Spectrum Distribution of the Speckle Pattern Interferometry

To improve the accuracy of the transient temperature detection system, Transient temperature inversion processing algorithms is proposed based on spectrum analysis of speckle pattern interferometry. The interference fringes are formed by speckle interferometry in the system. For transient temperature changes cause the material strain, the speckle interference pattern changes. The interference fringes on the measured surface are obtained by the area array CCD collection before and after deformation. The corresponding spectrum density function will changes by the changes of transient temperature, and the amplitude changes of center wavelength is inverted by the speckle pattern interferometry. Through detecting and calculating the ratio of the amplitude of the center wavelength, the transient temperature can be obtained by spectrum analysis. In the analysis and calculation for the function of transient temperature and material strain, material strain and interference fringes, derived the amplitude and phase function of the transient temperature change and interference fringes, so as to provide the necessary conditions for detecting the use of spectral density function temperature. 660 nm laser diode, and SI6600 type area CCD detector is used to obtain the speckle pattern interference fringes, system extracts the amplitude ratio of the central wavelength from spectral distribution function, and by calculation and calibration the detection accuracyoftemperature can be achieved of 2. Compared to traditional ±℃methods of direct detection forinterference fringes changes, the newmethodsimprove the accuracy by nearly an order of magnitude. It is more accuratedetection, betteruniformity and betterstability.