基于正交调制的偏振光谱成像系统研究

摘要

为了同时获取目标的全偏振二维图像信息和其光谱信息,设计了一种基于正交调制的偏振光谱成像系统.该系统由光学接收模块、相位调制器、Wollaston棱镜、Savart偏光镜、检偏器以及成像模块组成.其可以将原始光信号分解成两束相互正交的偏振光,并且分别成像在CCD焦平面的上下两部分上,从而构成两幅偏振图像.两组图像的叠加可以将干涉条纹的数据相互抵消,从而获得目标的纯图像信息,两组图像的相减可以将目标灰度图像相互抵消,从而获得目标的纯干涉条纹.通过理论分析与计算得到了光强分布函数和光谱变化形式.实验在稳定的光源环境中采用高对比度目标与背景板,完成了全偏振图像的实时采集.经相位校正和切趾处理改善了干涉图像的畸变,又通过去低频滤波和阈值滤波抑制了图像中背景噪声的影响,从而实现了对目标图像的提取及偏振光谱的复原.该系统具有稳定性高、光谱分辨率可调、信噪比高、可识别能力强等特点,对在复杂背景中提取目标图像、光谱及偏振态信息具有重要意义.%In order to obtain the complete polarized two-dimensional image information and its spectrum information at the same time ,a new polarized spectrum imaging system based on orthogonal modulation is designed .The system consists of optical an-tenna ,phase modulator ,Wollaston prism ,Savart polarizer ,analyzer and imaging module .The original optical signal is decom-posed into two beams of mutually orthogonal polarized light ,and they are respectively imaged in the upper and lower portions of the focal plane of the CCD ,so that it forms two full polarization images .The superposition of the two sets of images can cancel the data of the interference fringes to obtain pure image information of the target .The subtraction of the two sets of images can cancel the target gray scale images to obtain the pure interference fringes of the target .The light intensity distribution function and spectrum variation form were obtained by theoretical calculation .High contrast targets with background plates were used in the experiment ,real-time acquisition of fully polarized images was completed in a stable light source environment .The distortion of the interference image is improved by phase correction and apodization ,through high-pass filtering and threshold filtering ,the influence of background noise in the image is suppressed ,so that the extraction of the target image and the restoration of the po-larization spectrum are realized .It has the characteristics of high stability ,adjustable spectrum resolution ,high signal-to-noise ratio and strong ability to identify .It is important to extract the target image ,spectrum and polarization information in complex background .