基于散斑干涉光谱分布变化量探测瞬态高温的研究

Research on Transient Temperature Detection by Spectrum Function Variation of Speckle Pattern Interferometry

为了提高瞬态高温检测的精度,利用快速傅里叶变换(FFT)对散斑干涉条纹进行光谱分析,提出了通过光谱分布的偏移及幅值变化反演温度的方法。当激光照射应变材料时,瞬态高温使材料发生形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。由于其对应的光谱密度分布函数也会发生相应的改变,即中心波长位置偏移及振幅变化,通过其改变反演材料的瞬态温度。在分析推导了瞬态温度变化、材料应变及干涉条纹变化之间的函数关系后,仿真分析得到了瞬态温度正比于压强系数、反比于温度系数。实验采用660nm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的偏移量,经计算和标定所得数据与传统的干涉测温方法进行对比,探测精度可达0.3%。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近3倍。

To improve the accuracy of the transient temperature detection system, transient temperature inversion processing al- gorittmls was proposed based on spectrum analysis of speckle pattern interferometry. The interference fringes were formed by speckle interferometry in the system, and due to transient temperature changes that cause the material strain, the speckle inter- ference pattern changes. The interference fringes on the measured surface were obtained by the area array CCD collection before and after deformatiorL The corresponding spectrum density function will change with the changes in the transient temperature, and the amplitude changes of center wavelength were inverted by the speckle pattern interferometry. Through detecting and cal- culating 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, the amplitude and phase function of the transient temperature change and interference fringes were derived, providing the neces- sary conditions for detecting spectral density function temperature. The experiment used 660 nm laser diode and SI6600 type area CCD detector. By extracting the offset of the center wavelength from the spectrum distribution function, the calculation and cali- bration data were compared to the data obtained with the traditional method of interference temperature detection, and the result showed that the detection accuracy can achieve 0.3 %. Compared to traditional direct detection of interference fringes changes, the accuracy improved nearly three times by the method.