摘要
针对传统快照式光谱偏振成像系统难以兼具高偏振成像分辨率与高光谱分辨率的问题,提出基于空间维编码的两挡快速变焦快照式光谱偏振一体化成像方案。建立反远距型变焦物镜光焦度分配模型,设计出反远距系数为2.5的超长后截距变焦物镜,以解决光路遮挡难题;提出编码、偏振与色散等器件多参量联合优化方法,以提升系统光谱分辨率及像元匹配精度。设计出400~650 nm波段36 mm/109 mm两挡变焦高光谱偏振成像光学系统。设计结果表明,全焦段全视场全波段下调制传递函数(MTF)在144 lp/mm奈奎斯特频率处均大于0.205,光谱分辨率优于1.06 nm,空间分辨率在0.192 mrad和0.064 mrad之间可调,满足成像要求。通过搭建原理验证系统,标定偏振度精度、光谱偏振成像分辨率和光谱重构精度,开展动态目标成像实验,通过单次曝光获取目标行驶速度为10 m/s的高光谱偏振图像,与传统的强度图像相比,目标对比度提升50.36%以上,这验证了所提方案的可行性。本研究为未来机载高光谱偏振成像系统的设计与应用提供了理论支撑。
Objective Snapshot hyperspectral polarization imaging technology combines spectral imaging and polarization imaging,allowing for the simultaneous acquisition of hyperspectral,polarization,and spatial information.This forms a fourdimensional data cube of the target,expanding the dimensions of target information perception.The system finds wide applications in marine environment monitoring,earth remote sensing,forest resource exploration,military reconnaissance,and search and rescue operations.However,current hyperspectral polarization imaging systems,developed by various research institutions,typically use a fixed-focus system,which struggles to integrate high polarization imaging resolution with high spectral resolution.Improving spectral resolution often limits polarization imaging resolution,resulting in unclear target imaging.In this paper,we propose an integrated imaging solution based on spatial dimension coding.The design maintains constant spectral resolution while improving polarization imaging resolution when switching between short and long focal lengths.The system enables wide-field scanning in the short-focus state and highresolution imaging in the long-focus state,broadening the application scope of hyperspectral polarization imaging technology.Methods First,the initial structural parameters of the front zoom objective are determined by establishing a focal distribution model for the reverse telephoto zoom objective.An ultra-long rear intercept zoom objective with a reverse telephoto coefficient of 2.5 is designed to address the issue of optical path occlusion.Next,the coupling relationship between stop position and uniformity of image surface illuminance is analyzed,and the optimal stop position is determined to improve the accuracy of polarization information acquisition at the edges of the system's field of view.In addition,a digital micromirror device(DMD),relay mirror,imaging mirror,micro polarizer array(MPA),and spectral resolution are proposed to improve both the system's spectral resolution and pixel matching accuracy.Based on this analysis,a snapshot hyperspectral polarization two-speed zoom imaging optical system is designed,and its imaging quality is evaluated.Finally,a verification experiment is conducted to demonstrate the feasibility of the proposed scheme.Results and Discussions After completing the overall optical design,at a Nyquist frequency of 144 lp/mm,the modulation transfer function(MTF) of the system across the full focal range,field of view,and wavelength band,along both the meridional and sagittal planes,exceeds 0.205(Fig.7),indicating excellent imaging quality.When switching between short and long focal lengths,the spectral resolution remains stable(Fig.8).Moreover,in the 400-650 nm band,the spectral resolution is better than 1.06 nm,providing high spectral fidelity.The degree of linear polarization(DOLP)error test reveals that the DOLP error is less than 4.8%,confirming strong polarization retention(Table 5).The resolution plate imaging experiment(Fig.11) demonstrates improved polarization imaging resolution after switching focal lengths,with the short-focus state achieving 4.36 mrad and the long-focus state achieving 1.39 mrad.Spectral reconstruction accuracy was further verified through imaging experiments with color pens(Fig.12).The system's measured reflectance was compared with that of a commercial spectrometer,showing that the reflectance characteristic peaks closely matched,confirming high spectral reconstruction accuracy and the system's strong spectral resolution.Finally,field tests were conducted,where the system successfully imaged a moving car.From the DOLP images,we can clearly distinguish the front and rear of the vehicles(Fig.13),verifying the system's ability to capture spectral polarization information and effectively image dynamic targets under natural lighting conditions.Conclusions In this paper,we propose an integrated spectral polarization imaging scheme based on spatial dimension coding.Utilizing a two-speed zoom mechanism,the system achieves a triple zoom effect while maintaining strong imaging performance.When switching from the short-focus to the long-focus state,the spectral resolution remains unchanged,while the polarization imaging resolution is improved.Within the working spectrum of 400-650 nm,the spectral resolution exceeds 1.06 nm.The feasibility of the proposed scheme is validated through the setup of an experimental verification system and field experiments.The designed snapshot hyperspectral polarization two-speed zoom imaging optical system balances both high polarization imaging resolution and high spectral resolution.It is capable of adapting to fast-moving targets,quickly detecting,locking onto,and tracking them in real time.This enables the acquisition of a data cube encompassing the target's spatial,spectral,and polarization information,supporting target detection and recognition.The system has significant theoretical and practical implications for the future development and modeling of airborne snapshot spectral polarization imaging system.
作者
史浩东
范瑞晗
王稼禹
王祺
江晟
吴雨芳
李英超
付强
Shi Haodong;Fan Ruihan;Wang Jiayu;Wang Qi;Jiang Sheng;Wu Yufang;Li Yingchao;Fu Qiang(Jilin Provincial Key Laboratory of Space Optoelectronics Technology,Changchun University of Science and Technology,Changchun 130022,Jilin,China;School of Optoelectronic Engineering,Changchun University of Science and Technology,Changchun 130022,Jilin,China;School of Physics,Changchun University of Science and Technology,Changchun 130022,Jilin,China)
出处
《光学学报》
北大核心
2025年第1期204-217,共14页
Acta Optica Sinica
基金
国家自然科学基金青年科学基金(62405032)
吉林省教育厅项目(JJKH20230813KJ)。
关键词
成像系统
快照式高光谱偏振
变焦
光学设计
imaging system
snapshot hyperspectral polarization
zoom
optical design
