半波片角度失配对通道调制型偏振成像效果的影响及补偿  

Effect of half wave plate angle mismatch on channel modulating imaging result and its compensation

作　　者：李浩[1] 朱京平[1] 张宁[1] 张云尧[1] 强帆 宗康[1] 

机构地区：[1]电子物理与器件教育部重点实验室,陕西省信息光子技术重点实验室,西安710049

出　　处：《物理学报》2016年第13期114-120,共7页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:61205187);中央高校基本科研业务费专项资金(批准号:xkjc2013008)资助的课题~~

摘　　要：通道调制型偏振成像系统能够实时地对目标进行全偏振成像,是当前偏振成像领域的研究热点之一.基于萨瓦板的通道调制型偏振仪中半波片的光轴方向对成像结果的准确性有较大的影响.本文分析了半波片失配角的大小对探测器采集到的光强分布的影响,得到了二者之间的表达式,根据该表达式提出通过测量半波片失配角对系统进行定标并利用测得的半波片失配角对偏振成像的解调结果进行修正和补偿的方法.计算机仿真结果显示失配角为0.5?时,S1,S2和S3的解调结果准确度在经过修正补偿后分别提高了0.06%,3.49%和3.49%.表明该方法能够较好地对解调出的偏振斯托克斯参数图像进行补偿,得到更精确的成像结果,对提高通道调制型偏振成像的质量具有重要的意义.Polarization imaging technology is a powerful tool in remote sensing, bioscience, or other scientific areas science, and it can extract the polarization information of target effectively. As a novel polarization imaging technology, the channel modulating polarization imaging has been widely investigated in recent years, owing to its prominent advantages of compact, snapshot and full-Stokes acquirable. In the polarization imaging system based on Savart plate, a half wave plate with its optical axis at an angle of 22.5？is used to rotate the vibration direction of each incident light to ±45？. Thus, the amplitude of the light could be equally divided by the second Savart plate polariscope. Finally, the different components of light will interfere with each other on the focal plane and the target polarization information will be modulated in the interference pattern. Since the intensity distribution of interference pattern is sensitive to the orientation of the half wave plate, a small mismatch angle of half wave plate will lead to a wrong polarization image. In order to solve this problem, we investigate the relationship between the mismatch angle and the image intensity grabbed by focal plane array（FPA） and propose an error eliminating method to improve the accuracy of polarization imaging. We analyze how the mismatch angle α affects the light intensity and deduce the expression of the image obtained by the FPA. According to the expression, the raw image we grabbed directly by the FPA is a superposition of the modulated Stokes images with different carrier frequencies. Compared with the ideal expression, the expression we obtained shows that the channels of Stokes parameter S1 and S2,3each contain a constant factor which is related to the mismatch angle α. On the basis of this expression, we propose a method to measure the mismatch angle by imaging a target twice, one is behind a polarizer that is oriented at 0？and the other at 45？. Then we can calibrate the system by calculating the mismatch angle th

关 键 词：偏振成像 半波片 失配角 补偿 

分 类 号：O436.3[机械工程—光学工程]