摘要
红外成像仿真技术（IRI）能够很好地生成森林、城市和海洋等不同环境条件下的红外图像，在军事和民用等领域得到了广泛应用。海面红外成像仿真具有研发成本低、周期短和效率高等优点，对于构建海面或海下目标识别算法具有重要意义，成为了海洋安全维护不可或缺的环节。论文旨在研究不同气象条件下的海面红外图像仿真。
论文使用MATLAB软件建立海面红外辐射大气传输模型，并对大气中光子的行走路径进行模拟，利用计算机仿真红外成像系统生成海面红外图像。论文主要由三部分构成：大气传输模型的构建、大气点扩散函数的模拟和红外成像系统的仿真。通过光谱透过率表和Kim模型建立红外辐射大气传输衰减模型，计算红外辐射大气透过率，并综合考虑太阳辐射直射强度模型，建立红外辐射大气传输模型，生成经过大气传输后的海面红外辐射场；考虑大气中分子、气溶胶粒子对光子的碰撞，分别使用蒙特卡罗方法和基于人工神经网络的方法获得大气点扩散函数（PSF），以模拟光子在大气中的行走过程，该函数用于与经过大气传输的海面红外辐射场进行卷积，生成的辐射场作为红外成像系统的输入；使用调制传递函数分别描述光学系统、探测器和电子电路对成像质量的影响，三者的乘积即为完整的成像系统的调制传递函数，用于模拟红外成像系统的成像效应。综合上述从海面发射红外辐射到红外成像系统生成图像过程中的所有影响因素，形成一套比较完整的海面红外成像仿真系统，并生成海面红外仿真图像。
实验结果表明建立的红外辐射大气传输衰减模型能够保证大气透过率的计算误差小于20%。经过大气传输模型生成的海面红外图像明显变暗，对比度降低。人工神经网络训练完成后，其计算一次的时间远小于蒙特卡罗方法的计算时间，保证了海面红外图像仿真的实时性。光学系统、探测器和电子电路系统三者可以近似看作低通滤波器，会造成图像高频信息的丢失。另外，光学系统对图像的渐晕效果会造成图像中央区域变亮，周围区域变暗。
关键词：海面红外成像仿真；大气传输模型；PSF；红外成像系统
Abstract
Widely applied in both military and civil fields, infrared image (IRI) simulation technique works well in generating infrared images under various ttings such as the forest, city and ocean. Enjoying advantages of low development costs, short development circles and high efficiency, a surface IRI simulation is of great significance in constructing target detection algorithms to recognize targets above or below a surface. As a result, a surface IRI simulation has become an indispensable part of maintaining marine safety. This paper aims to study a surface IRI simulation under different meteorological conditions.
In this paper, Matlab was ud to build up the atmospheric transmission model of a surface infrared radiation. Then the pathways of photons in the atmosphere were simulated, and a simulation algorithm of IRI system was designed to generated a surface IRI. This paper consists of three parts: establishing the atmospheric transmission model, simulating atmospheric point spread function (PSF), and developing the IRI simulation system. First, an atmospheric attenuation model of infrared radiation was established through atmospheric spectral transmittance table and Kim model, to calculate the transmittance of infrared radiation. By adding the direct radiation density model of the sun into consideration, the atmospheric transfer model was completed to generate the infrared radiation field from a surface. Also, taking the collisions between photons and neutron as well as aerosol particles into consideration, PSF was estimated with Monte Carlo method (MC) and artificial neural network (ANN). The function performs convolution to the radiation field of infrared radiation from a surface, who result rves as the input of IRI system. Furthermore, modulation transfer function (MTF) was designed to describe the influence of the optical system, detector, and electronic circuit on the final imaging quality. Specifically, the product of three sub-system functions results in the overall MTF, as ud to simulate the imaging effect of the IRI system. Considering all the above factors from the formation of infrared radiation field to back-end image generation, an intact system of a surface IRI simulation system is propod and simulated images are generated.
As indicated in the experiments, the established atmospheric transfer model guarantees that the error of atmospheric transmittance is within 20%, compared to actual measurement. It is noticed that after atmospheric transmission, the infrared images on the a surface remarkably become darker, with lower contrast. After training, ANN shows great advantages over MC on prediction time, with similar accuracy, better ensuring the real-time requirement of the system. Also it is concluded that optical system, detector, and electronic circuit can be viewed as low-pass filter, resulting in loss of high-frequency information. In addition, vignetting effects of optical systems will cau images to be brighter in the center, but darker on the edges.
Keywords: a surface infrared imaging simulation, atmospheric transmission model, PSF, infrared imaging system香辣皮皮虾
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目录
摘要 ............................................................................................................................... I Abstract ............................................................................................................................. I I 第1章绪论 (1)
1.1 课题背景及研究目的和意义 (1)
1.2 国内外研究现状分析 (2)
1.2.1 红外辐射大气传输效应研究现状 (2)
1.2.2 红外成像仿真研究现状 (3)
1.3 主要研究内容 (5)
1.4 论文结构安排 (6)
第2章红外成像辐射理论 (8)水利建设与管理
2.1 基本辐射量 (8)
2.1.1 辐射功率 (8)
2.1.2 辐射出射度 (8)
2.1.3 辐射强度 (9)
2.1.4 辐射亮度 (9)
2.1.5 辐射照度 (10)
2.2 基本辐射定律 (11)
2.2.1 朗伯余弦定律 (11)
2.2.2 普朗克定律 (11)
2.2.3 斯蒂芬-玻尔兹曼定律 (13)
2.3 大气窗口 (13)
2.4 海面红外成像仿真原理 (14)
塞上长城2.5 本章小结 (15)
第3章海面红外辐射大气传输模型的建立 (16)
3.1 海面辐射大气传输方程 (16)
3.2 大气透过率计算模型 (17)
3.2.1 大气分子吸收的影响 (17)
3.2.2 大气散射的影响 (19)
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3.2.3 仿真结果与分析 (20)
3.3 太阳辐射直射强度模型 (23)
3.4 本章小结 (26)
第4章大气点扩散函数 (27)
4.1 基于蒙特卡罗法建立大气点扩散函数 (27)
机遇的近义词4.1.1 蒙特卡罗随机模拟方法 (27)
4.1.2 大气点扩散函数的建立 (28)
4.1.3 结果分析 (30)
凉拌小白菜4.2 蒙特卡罗法速度优化 (33)
4.2.1 人工神经网络的建立 (33)
4.2.2 结果分析 (35)
4.3 本章小结 (36)
第5章红外成像系统仿真 (37)
5.1 红外成像系统仿真原理 (37)
5.2 图像质量评价标准 (39)
5.3 光学系统MTF (40)
5.3.1 渐晕现象 (40)
5.3.2 空间效应MTF (44)
5.4 探测器MTF (46)
布城5.4.1 探测器空间滤波MTF (47)
5.4.2 探测器时间滤波MTF (47)
5.5 电子电路系统MTF (49)
5.5.1 低通滤波电路MTF (50)
5.5.2 CCD转移MTF (51)
5.6 红外系统噪声模型 (51)
5.7 海面红外成像仿真结果 (52)
5.8 本章小结 (54)
结论 (55)
参考文献 (57)
攻读学位期间发表的学术论文 (60)
(61)
