基于AOTF分光和LCVR相位调制型光谱偏振成像技术研究

发布时间：2018-06-19 14:09

本文选题：AOTF + LCVR　；参考：《中北大学》2017年硕士论文

【摘要】：光谱偏振成像技术(Spectropolarimetric imaging,SPI),是一种集空间目标二维影像、光谱、偏振于一体的新型光信息获取和应用技术,该技术可获取光谱成像所无法获取的目标光独有的偏振特性,多维信息的综合利用可以进一步来提高目标识别探测能力。所以目前该技术广泛应用于军事探测、医疗检测和大气污染监测等领域。论文基于声光可调滤波器(Acousto-optic tunable filter,AOTF)分光和液晶可变相位延迟器(Liquid crystal variable retarder,LCVR)相位调制相结合的新型光谱偏振成像技术原理,为了实现系统光谱和偏振的精确和快速测量,对影响系统测量精度的原因进行了理论分析和实验修正,并提出了斯托克斯(Stokes)参量的快捷测量方法。因此,本论文主要从以下几个方面来展开阐述研究。首先对AOTF和LCVR的工作原理及其基本性能进行了研究。详细的从压电换能器声场衍射角度分析了光谱展宽的原因;并根据AOTF分光机理,理论分析了不同入射光极角导致AOTF?1级衍射光中心波长变化的原因,为下一步AOTF的光谱校正和实现光谱精密测量提供了坚实的理论基础。其次,提出了一种双LCVR相位调制和AOTF分光的全新高光谱全偏振成像系统,在分析了光的偏振态和典型器件的米勒矩阵的基础上,针对系统特点建立了适用于该系统的光谱偏振测量模型,并首次提出了一种被测目标光的Stokes参量的快捷获取方法。再次,为了实现提出系统高精度的光谱测量,对光垂直和非垂直入射AOTF导致衍射光中心波长变化进行了精确定标研究,并通过最小二乘非线性拟合得到了光谱修正方程;为了实现高精度的偏振测量,提出了LCVR对不同波长光波初始相位延迟量的最小二乘精确定标研究,并得到了初始相位延迟量定标方程,并实验验证了该方程的精确性。最后,根据上述所提出的系统,搭建了实验样机。利用样机对上述所提出的被测目标光Stokes参量的快捷测量方法进行了实验性验证,而且还利用样机进行了外场的光谱实验和光谱偏振实验,实验验证了该系统进行光谱偏振成像方面的可行性和可靠性。
[Abstract]:Spectropolarimetric imaging is a new optical information acquisition and application technology, which integrates two-dimensional image, spectrum and polarization of spatial target. This technique can obtain the unique polarization characteristics of target light that cannot be obtained by spectral imaging. The comprehensive utilization of multi-dimensional information can further improve the ability of target recognition and detection. Therefore, the technology is widely used in military detection, medical detection and air pollution monitoring and other fields. Based on the principle of novel spectral polarization imaging based on acousto-optic tunable filter and liquid crystal variable retarderor LCLC phase modulation, in order to realize the accurate and fast measurement of the spectrum and polarization of the system, this paper presents a novel spectral polarization imaging technique based on the combination of acousto-optic tunable filter and liquid crystal variable retarderer LCLC phase modulation. Theoretical analysis and experimental correction of the reasons affecting the measurement accuracy of the system are carried out, and a quick measurement method for Stokes parameters is proposed. Therefore, this paper mainly from the following aspects to start the study. Firstly, the principle and basic performance of AOTF and LCVR are studied. The cause of spectrum broadening is analyzed in detail from the angle of acoustic field diffraction of piezoelectric transducer, and according to the principle of AOTF, the reason that the center wavelength of AOTF1 diffracted light varies with different incident pole angles is analyzed theoretically. It provides a solid theoretical basis for the spectral correction of AOTF and the realization of precise spectral measurement. Secondly, a novel hyperspectral full polarization imaging system with dual LCVR phase modulation and AOTF-splitting is proposed. Based on the analysis of the polarization state of light and the Hans Muller matrix of typical devices, a novel hyperpolarizing imaging system is proposed. According to the characteristics of the system, a spectral polarization measurement model is established, and a fast method for obtaining Stokes parameters of the target light is proposed for the first time. Thirdly, in order to achieve high precision spectral measurement, the wavelength variation of diffraction light caused by vertical and non-vertical incident AOTF is accurately calibrated, and the spectral correction equation is obtained by least square nonlinear fitting. In order to achieve high precision polarization measurement, the least square accurate calibration of the initial phase delay of different wavelength light waves by LCVR is proposed, and the calibration equation of initial phase delay is obtained, and the accuracy of the equation is verified by experiments. Finally, an experimental prototype is built according to the proposed system. The fast measurement method of the light Stokes parameters of the target is experimentally verified by the prototype, and the spectral and polarization experiments are also carried out in the field. Experiments show that the system is feasible and reliable in spectral polarization imaging.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O436.3

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