光学表面频段误差对成像质量的影响研究

	光学表面频段误差对成像质量的影响研究
	曾雪锋
学位类型	博士
导师	张学军
	2014-07
学位授予单位	中国科学院大学
学位专业	光学工程
摘要	高精度复杂光学曲面是高分辨率空间对地光学遥感系统的核心元件，制造精度和加工能力是制约高分光学系统研制的瓶颈技术之一。现有加工技术在工件表面残留的加工误差会影响高分辨率系统的频率响应及信噪比等系统性能，进而影响系统成像质量。新型的高分辨率系统对反射镜制造提出了更高的要求，传统的面形质量评价方法已无法满足高面形质量约束需求，因此，进一步研究超高精度光学元件的面形表征方法，研究在衍射极限条件约束下光学表面频段误差对系统成像质量的影响，对于提升高分辨率空间对地光学遥感系统的成像质量具有重要研究意义。不同频段误差对系统性能的影响不同，最终会对所成图像清晰度、锐度和对比度等参数带来不同影响。因此对光学表面全频段误差的幅值、频谱、分布形式等提出明确控制目标，实现其一致收敛是高分辨率成像系统制造的必然要求。根据频段误差对光学系统性能影响特征，对全频段误差进行划分，通过光学系统成像仿真研究，揭示光学表面低、中、高频误差对光学系统成像质量的影响规律，从而确定光学加工过程中各频段允差。并结合现代光学加工技术特征，建立光学表面全频段误差评价体系，一方面为加工提供指导，另一方面为光学设计和系统性能预估提供参考。论文的主要内容包括以下四部分： 1、对光学表面全频段误差进行划分光学表面误差包含了中低频误差的分布、中高频误差的统计学信息等内容，最终通过对系统波像差和系统杂散光的影响体现在光学系统的成像质量上。根据成像光学系统镜面空间频段误差的表面周期长度，建立全频段误差表征模型，将频段误差分为三个部分； 2、研究光学表面各频段误差对光学系统性能参数的影响为了研究光学表面制造残差对成像系统性能的影响，提出了基于光学系统出瞳位相差的空间频段误差划分方法，推导出了统计意义下的中频误差对光学传递函数的影响函数解析式，确定了MTF受中频误差影响的特征分辨率。对比低频误差与中频误差影响的区别，中频误差导致系统调制传递函数从低分辨率处开始迅速下降，并根据中频影响函数解析式得到中频误差导致调制传递函数曲率突变特征分辨率； 3、研究了光学系统性能参数对成像质量的影响将实际制造参数代入光学系统设计中，根据实际制造结果，仿真分析了系统性能与制造误差间的关系。研究了光学系统各性能参数对图像质量参数的影响，分别分析了光学加工误差对近衍射限系统成像后图像亮度、对比度、分辨率、锐度的影响下降，从而可能导致光学系统的成像质量下降。如何分析这些因素对光学系统的具体影响，是预估空间光学系统成像质量的关键； 4、进行成像实验，分析各频段误差对光学系统成像质量的影响在衍射置限有限物距同轴成像系统中通过位相板引入相同幅值不同频率系统波像差，分析各频段误差对图像质量的影响。本论文围绕着光学表面频段误差对系统成像质量开展研究工作，完成了光学表面全频段误差建模和划分方法研究，基于仿真方法研究了全频段误差对系统频率响应和信噪比参数的影响，通过调制系统波像差推导了统计意义下中频误差对系统光学传递函数和点扩散函数的影响，针对衍射置限有限物距同轴成像系统进行了频段误差对系统成像质量影响的实验，以探索频段误差对无限远物距成像的空间望远镜成像质量的影响。
其他摘要	High precision optical surface is the core components of high-resolution optical remote sensing system, while manufacturing precision and processing ability limit the development of the high-resolution optical system. Existed processing technology could produce errors which affect the high-resolution system’s performance, such as the frequency response and SNR, thus have further influence on the imaging quality. The new high-resolution system puts forward higher requirements to the fabrication of reflector, however, the traditional evaluation methods are unable to meet the demand of high surface quality. Therefore, further study on surface characterization methods of ultra-high-precision optical elements, and the impact of the surface frequency error on the system imaging quality under the diffraction limitation are significant to improve the imaging quality of the high-resolution space optical remote sensing system. Errors in different frequency range have different point spread function (PSF). Finally, they bring different effects on the image resolution, sharpness, contrast, and so on. Hence, it is necessary to put forward clear goals on the amplitude, spectrum and distribution form of full frequency error and realize its uniform convergence as for manufacturing high-resolution imaging system. According to the influence of frequency error on the optical system performance, a dividing method of full frequency error has been put forward. The optical system imaging simulations reveal the influences of the optical surface’s low, middle, high frequency on the imaging quality of optical system, thus the tolerance of different frequency band could be determined. Combined with modern optical processing technology, an evaluation system of full frequency error has been set up. On one hand, it provides guidance to processing, on the other hand, it provides references to optical design and system performance prediction. The thesis includes four parts as follows. 1, The division of optical surface full frequency error. Optical surface error contains the distribution of the low-middle frequency error and the statistical information of middle-high frequency error. They affect the system wave aberration and stray light, and finally influence the optical system imaging quality. According to the special frequency error’s periodicity of imaging optical system, a full frequency error characterization model is established, and the frequency error is divided into three parts; 2,Research on optical surface frequency error's influences on the performance of optical system. To research the effect of optical surface residual on the performance of imaging system, spatial frequency error division method is proposed based on the phase difference of optical system pupil. The analytic expression, which manifest the influence of the Mid - Spatial Frequency Errors (MSF) on modulation Transfer Function (MTF), has been derived in statistical sense. And the MTF featured resolution affected by the mid-spatial frequency error has been determined. The influence of low-spatial frequency error and mid-spatial frequency error has been compared. The mid-spatial frequency error causes the rapid decline of MTF at low resolution, and that feature resolution of MTF is obtained according to the analytic expression of mid-spatial frequency error influence function. 3, The study of the optical system performance parameters’ influence on imaging quality. Substituting the actual manufacturing parameters into optical system design, the relationship between the system performance and the processing error are analyzed according to the actual manufacturing results. The influence of optical processing error on the image of diffraction limited system. The system PSF is calculated by the wave aberration containing frequency error. Such PSF can be used to perform the image degradation, and the brightness, contrast, resolution and sharpness of the degraded image are calculated. Hence, the influences of frequency error on optical system imaging quality are studied. How to analyze the specific influence of these factors on the optical system is important to forecast the space optical system imaging quality; 4,Imaging experiments, and analyzing the influence of frequency error on optical system imaging quality. In the diffraction limited finite distance coaxial imaging system, wave aberration with different amplitude and frequency is introduced by the phase plate, and the influences of frequency error on imaging quality are analyzed. This paper mainly researches the influences of optical surface frequency error on the system imaging quality. Modeling of full frequency error and dividing method are completed. The impacts of full frequency error on the system frequency response and signal-to-noise ratio are studied by simulation. The influences of mid-spatial frequency error on system MTF and PSF were deduced in statistical significance. The experiments on the diffraction limited finite distance coaxial imaging system are conducted, in order to study frequency error’s influence on imaging quality and explore the impacts of frequency error on the imaging quality of infinite distance space telescope.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41391
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	曾雪锋. 光学表面频段误差对成像质量的影响研究[D]. 中国科学院大学,2014.

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