大视场高分辨率成像光学系统设计研究

发布时间：2018-08-22 15:04

【摘要】：随着光电成像技术的发展,为了获取更大空间范围以及更多空间细节的目标图像信息,光电成像系统逐步向大视场和高分辨率的方向发展。对于单一的光学系统,总信息量由成像芯片的像元数决定。总信息量一旦确定,视场与分辨率就成为一对相互矛盾的参数,即不能同时提高光学系统的视场和分辨率。一般而言,大视场的光学系统往往分辨率比较低;高分辨率的光学系统往往视场比较小。因此,解决视场与分辨率之间的矛盾,同时实现大视场与高分辨成像是目前光学领域的研究热点。大视场高分辨的光学系统在航天遥感、航空侦察、安防监控、天文观测及文物保护等军事和民用领域具有广泛的应用前景。论文以大视场高分辨率成像为研究主题,以离轴三反光学系统、离轴四反光学系统、同心多尺度光学系统及曲Petzval像面光学系统为研究对象,主要进行了以下四方面的研究:1)离轴三反光学系统设计研究。以反射定律和正弦条件为基础,推导了一组用于求解同轴三反初始结构的Wassermann-Wolf(W-W)微分方程。利用该方程解算出次镜和三镜的面型数据点,通过多项式拟合W-W曲面,获得了像质良好的同轴三反初始结构。以此初始结构为设计起点,应用偶次非球面,设计了一款焦距为1.2m、视场为18o?4o、F/4的离轴三反光学系统。系统各个视场的调制传递函数在50 lp/mm处均大于0.5,成像质量良好。此外,系统的主镜为二次曲面、次镜和三镜为非球面,3个反射镜均无偏心和倾斜,有效地降低了制造成本和装调难度。2)离轴四反光学系统设计研究。研究了离轴光学系统的矢量像差理论和各像差的节点特性。对同轴四反光学系统进行了像差分析,建立了由带权重的初级像差系数和结构布局约束条件所组成的目标函数。通过遗传算法对目标函数进行优化求解,解算出同轴四反光学系统的结构参数,获得了像质良好和特定结构布局的同轴四反初始结构。选择遮拦比最小的初始结构为设计起点,应用Zernike自由曲面,最终设计了一款焦距为1.2m、视场为30o?4o、F/4的离轴四反光学系统。系统结构布局紧凑,各个视场的调制传递函数在40 lp/mm处均大于0.52。3)同心多尺度光学系统设计研究。同心多尺度光学系统可以解决视场与分辨率之间的矛盾,是目前同时实现大视场和高分辨成像的最佳手段。研究了同心多尺度设计理论,推导了同心球透镜的焦距公式、消色差条件及消球差条件,分析了同心球透镜的像面移动问题。对中继微相机进行了像差分析,研究了微相机的视场重叠及排布方式。基于同心多尺度设计理论,设计了一款焦距为35mm、视场为120o?60o、F/2.8的十亿像素同心多尺度光学系统。各视场的调制传递函数在270 lp/mm处均大于0.3。该光学系统由104个微相机组成,微相机按照基于正二十面体的最密方式排布,填充率可达76.6%。最后对同心多尺度光学系统进行了公差分析。4)曲Petzval像面光学系统设计研究。为了更精确的评估曲面像面光学系统的畸变,提出了弧长畸变的概念。通过编写宏程序约束像面与Petzval面重合,设计了一款焦距为100mm、视场为40o、F/2.8的曲Petzval像面光学系统。系统各视场的调制传递函数在100 lp/mm处均大于0.69,相对照度92.4%,弧长畸变0.5%。与传统光学系统相比,曲Petzval像面光学系统具有结构紧凑、元件数量少、像差校正能力强、光焦度分配均匀及镜头对称度高等光学优势。曲Petzval像面光学系统为大视场高分辨率成像提供了新的发展方向。
[Abstract]:With the development of optoelectronic imaging technology, in order to obtain the target image information with larger spatial range and more spatial details, optoelectronic imaging system is gradually developing towards the direction of large field of view and high resolution. As a pair of contradictory parameters, it is impossible to improve both the field of view and the resolution of the optical system. Generally speaking, the resolution of the optical system with large field of view is often lower; the field of view of the optical system with high resolution is often smaller. Research hotspots in the field of science. Large-field high-resolution optical systems have wide application prospects in military and civil fields such as space remote sensing, aeronautical reconnaissance, security monitoring, astronomical observation and cultural relics protection. The optical system and the curved Petzval image plane optical system are studied in the following four aspects: 1) The design of off-axis three-mirror optical system is studied. Based on the reflection law and sinusoidal condition, a set of Wassermann-Wolf (W-W) differential equations for solving the initial structure of coaxial three-mirror are derived. An off-axis triaxial optical system with a focal length of 1.2m, a field of view of 18o?4o and an F/4 is designed by using an even aspheric surface. In addition, the main mirror of the system is quadric, the secondary mirror and the three mirrors are non-spherical, and the three mirrors are non-eccentric and inclined, which effectively reduces the manufacturing cost and the difficulty of assembly and adjustment. 2) The design of the off-axis four-mirror system is studied. The vector aberration theory and the node characteristics of each aberration are studied. An objective function consisting of weighted primary aberration coefficients and structural layout constraints is established. The objective function is solved by genetic algorithm and the structural parameters of the coaxial four-mirror optical system are solved. The coaxial four-mirror initial junction with good image quality and special configuration is obtained. An off-axis four-mirror optical system with a focal length of 1.2m, a field of view of 30o?4o and an F/4 is designed by using Zernike free-form surface. The structure of the system is compact and the modulation transfer function of each field of view is greater than 0.52.3 at 40 lp/mm. The design of a concentric multi-scale optical system is studied. Multiscale optical system can solve the contradiction between field of view and resolution, and is the best way to realize large field of view and high resolution imaging at the same time. The theory of concentric multiscale design is studied, the focal length formula of concentric spherical lens, achromatic condition and spherical aberration condition are deduced, and the image plane movement of concentric spherical lens is analyzed. Based on the concentric multi-scale design theory, a 1-billion-pixel concentric multi-scale optical system with a focal length of 35mm, a field of view of 120o? 60o and an F/2.8 pixel is designed. The modulation transfer function of each field of view is greater than 0.3 at 270lp/mm. The optical system consists of 104 microphases. Finally, the tolerance analysis of the concentric multi-scale optical system is carried out. 4) The optical system design of curved Petzval image plane is studied. In order to evaluate the distortion of the optical system more accurately, the concept of arc length distortion is proposed. A curved Petzval image plane optical system with focal length of 100 mm, field of view of 40 O and F/2.8 is designed. The modulation transfer function of each field of view is greater than 0.69 at 100 lp/mm, relative illumination 92.4% and arc length distortion 0.5%. Compared with the traditional optical system, the curved Petzval image plane optical system has compact structure and the number of components. The optical system of curved Petzval image plane provides a new development direction for large field of view and high resolution imaging.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH74

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