湍流图像退化中的模糊与畸变  

Blur and Distortion in Turbulence-degraded Image

作　　者：李尚蔚 任益充 李昕淼 梅海平 陶志炜 刘世韦 饶瑞中 LI Shangwei;REN Yichong;LI Xinmiao;MEI Haiping;TAO Zhiwei;LIU Shiwei;RAO Ruizhong(School of Environmental Science and Optoelectronic Technology,University of Science and Technology of China,Hefei 230026,China;Key Laboratory of Atmospheric Optics,Anhui Institute of Optics and Fine Mechanics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;School of Physics,Hefei University of Technology,Hefei 230009,China;Science Island Branch,Graduate School of USTC,Hefei 230026,China)

机构地区：[1]中国科学技术大学环境科学与光电技术学院,合肥230026 [2]中国科学院合肥物质科学研究院安徽光学精密机械研究所中国科学院大气光学重点实验室,合肥230031 [3]合肥工业大学物理学院,合肥230009 [4]中国科学技术大学研究生院科学岛分院,合肥230026

出　　处：《光子学报》2024年第8期29-38,共10页Acta Photonica Sinica

基　　金：国家自然科学基金(No.62301530);红外与低温等离子体安徽省重点实验室(No.IRKL2023KF05);中国科学院合肥物质科学研究院院长基金(No.YZJJ2023QN05)。

摘　　要：基于光线传播以及相位叠加原理,构建了湍流图像退化模型,获得了湍流下目标对应的点扩散函数,并通过调制传递函数面积以及等晕角验证了仿真模型。同时,通过平均相关系数定义了像方近似不变区域,像方近似不变区域有助于对点扩散函数变化程度的理解。通过光线在湍流中的传播过程,猜测图像退化的模糊与畸变的程度和湍流的分布有关。为验证以上猜测,设置了两种极端情况下的湍流分布情形进行仿真实验,并通过调制传递函数面积以及像方近似不变区域对仿真结果进行分析。结果表明在同等湍流强度情况下,靠近镜头端的湍流会对图像造成更多的模糊效应,靠近物体端的湍流会对图像造成更多的畸变效应。基于此,解释了在湍流图像退化模型中采用先畸变后模糊是更为合理的操作,并建议湍流复原算法应根据退化结果中的模糊与畸变的程度采取相应的复原措施。Incoherent light imaging has been widely used in astronomical observation,industrial production,medical treatment and other fields.It is of great value to study the theory and application of incoherent light imaging.However,incoherent light imaging in atmospheric environment is inevitably affected by atmospheric turbulence,which leads to blur and distortion of the image,and degrades the quality of the image obtained.Blur is the high-order aberration caused by turbulence,which makes the light unable to effectively concentrate on one point to smooth the image,while distortion is caused by the nonlinear change of wavefront phase,which makes the image pixels move.The degradation of image in turbulent flow can be expressed as the superposition of the point spread function corresponding to multiple point sources,and the blur and distortion of the point spread function also reflect the degradation degree of the image.The blur and distortion caused by turbulence are important factors limiting the application of incoherent imaging.It is important to study the blur and distortion of point spread function caused by turbulence to alleviate the degradation of turbulent image.In the current methods of turbulence image degradation,many algorithms are based on the condition of isoplanatism,and the anisoplanatism of turbulence can not be ignored.A t t he s ame t ime,there is a lack of research and analysis on the blur and distortion of the point spread function under anisoplanatic conditions.In order to simulate the anisoplanatic effect,a turbulence imaging model is constructed based on the principle of ray propagation and phase screen superposition.The wavefront phase corresponding to the target point source can be calculated,and the point spread function corresponding to the target point source can be obtained by Fourier transform.The model can simulate the light emitted by different point sources through different turbulent paths to obtain the blur and distortion under anisoplanatic conditions.Since the scenario of horizontal

关 键 词：湍流图像退化 图像模糊 图像畸变 调制传递函数面积 平均相关系数 

分 类 号：O438[机械工程—光学工程]