【作者】 张敏娟；

【导师】 王召巴； 王志斌；

【作者基本信息】 中北大学 ， 光电子技术与仪器， 2013， 博士

【摘要】 弹光调制傅里叶变换光谱技术是一种高速、宽光谱、高灵敏度的傅里叶变换光谱技术,其在宇宙探测、环境监测、生物医学、工业生产等瞬态光谱探测领域具有潜在的应用价值。弹光调制器作为弹光调制傅里叶变换光谱仪的核心技术和部件,其调制频率高、光程差呈非线性,使得弹光调制数据处理技术存在难题。因此,如何实现弹光调制干涉信号的高速采样和存储、准确计算弹光调制傅里叶变换干涉仪的瞬态最大光程差,以及如何快速准确地进行光谱复原、标定,成为弹光调制傅里叶变换光谱仪需要解决的重要科学问题。论文基于傅里叶变换光谱复原数据处理技术和弹光调制傅里叶变换干涉仪的工作机理,对弹光调制傅里叶变换光谱复原高速数据处理技术进行研究,开发了弹光调制傅里叶变换高速数据处理平台。首先,研究了傅里叶变换光谱复原数据处理技术。基于傅里叶变换光谱理论,分析了时问调制型傅里叶变换干涉仪的工作机理、光谱分辨率和采样方式；为了抑制频谱泄露、减小相位歪曲,对傅里叶变换干涉图的切趾、相位校正技术进行了研究,基于Forman法和Mertz法的相关特性,提出了对称化相位校正方法。该方法采用高分辨率的干涉图对相移频谱进行估计,在频域内完成复原光谱的相位校正。实验表明,该方法使得复原光谱保持了比较高的准确度,同时降低了算法复杂度。其次,以弹光调制傅里叶变换干涉仪的工作机理为立足点,建立了弹光调制器的动态模型,针对弹光调制干涉信号的高速、相位非线性特性,采用高速等时间方式实现了干涉信号采样；以激光为参考光源,通过激光干涉信号过零计数的方法实现了瞬态最大光程差的检测,完成了光谱复原和波长标定。再次,针对弹光调制干涉信号相位非线性特性,通过分析非均匀离散傅里叶变换算法、D-R算法和基于傅里叶变换矩阵的非均匀快速傅里叶变换算法,提出了加速的非均匀快速傅里叶变换算法。该算法通过核函数卷积运算对傅里叶系数进行估计,实现了均匀数据的插值。实验验证,该算法在合理选择高斯核函数和参数时,能快速准确地复原激光光谱和黑体光谱。最后,基于FPGA+DSP架构,设计了弹光调制高速数据处理平台。以高速ADS4245模数转换器和DDR3动态存储器实现了干涉信号的高速采集和存储,基于DSP实现了快数据处理算法,完成了光谱复原。为了验证该平台的性能,搭建了完整的光谱测试系统,以已知频谱的窄带激光和不同温度的红外黑体为辐射源对其光谱进行快速复原,验证了该系统的性能,达到了指标要求。更多还原

【Abstract】 The technology of the photo-elastic modulation Fourier transform spectrometer (PEM-FTS) with high speed, wide spectrum and high sensitivity has potential application in the transient spectral detecting fields such as aerospace detection, environmental monitoring, biological medicine, industrial production and so on. As the core technology and unit the elasto-optical modulator has high modulation frequency and its modulated optical path difference is nonlinear,which result in the problem in the data processing technology of photo-elastic modulation.Wherefore, how to realize high-speed sampling and storage of elasto-optical modulation interference signal, to caculate accurately transient maximum optical path difference of elasto-optical modulation Fourier transform interferometer and how to make spectral reconstruction, calibration fast and accurate are the important science problems need to be solved.Based on the technology of spectral reconstruction data processing in the Fourier transform spectrometer and the principle of the photo-elastic modulation Fourier transform interferometer, the paper makes research to high speed data processing technology of PEM-FTS, develops the high-speed data processing platform of PEM-FTS.First, the study on the data processing technology in the Fourier transform spectral recovery is researched. Based on the Fourier transform spectral theory, the operating principle, the resolution and the sampling method in the time modulation Fourier transform spectrometer are analyzed; In order to suppression the spectral leakage, decrease the phase distort, the technology of truncation and phase correction are studied, and based on Forman and Mertz methods the interferogram symmetrization phase correction method is put forward. In the method the phase shift spectrum is estimated by the high resolution interferogram, and the phase-corrected technology of the rebuilt spectrum is realized in the frequency domain. It shows from experiment that the method decreased the complexity of the algorithm and has the comparativity high accuracy in rebuilt spectrum. Second, based on the principle of photo-elastic modulator Fourier transform interferometer, the dynamic model is built. In view of high speed and the nonlinearity of interference signal in the photo-elastic interferometer, the interference signal is high-speed sampled by the equal time intervals, and the transient maximum optial path difference is calculated by zero-crossing counting of laser’s interference signal when the laser is used as reference source, to accomplish the spectral reconstruction and the wavelength calibration of rebuilt spectrum.Third, according to the phase nonlinearity of the photo-elastic modulator interference signal, the nonuniform discrete Fourier transform algorithm, the D-R algorithm and the nonuniform fast Fourier transform algorithm based on Fourier transform matrix are analyzed, the accelerated nonuniform fast Fourier transform algorithm is put forward. In the method the Fourier coefficient is estimated by convolution arithmetic of kernel function to realize the uniform data interpolation. It is verified that the algorithm can rebuild the laser spectrum and blackbody spectrum fast and accurately when choose Gaussian kernel function and set parameters reasonablely.Last, based on FPGA+DSP framework, it sets up an elasto-optical modulation high-speed data process platform. Using high speed ADS4245ADC and DDR3dynamic RAM to realize the high speed sampling and storage of interference signal, it realizes the data processing in the spectral reconstruction based on DSP. In order to verify the performance of the platform, the complete spectrum test system is set up, using the known narrow-band laser and infrared blackbody with different temperature as radiation source to rebuild their spectrum, and the expected result is obtained.更多还原