基于散射介质成像理论的微光夜视系统研究

描述了一种基于大气散射特性分析的微光夜视系统设计。通过分析大气对光学辐射的散射作用,在理想光电成像系统探测方程的基础上,建立了散射介质成像的探测模型,表明大气散射会严重衰减目标对比度,而目标对比度的传递特性即系统调制传递函数将直接影响观察的作用距离。通过选择应用响应光谱主要集中于0.6μm~1.0μm的三代像增强器,优化设计光学系统的MTF,实现了大气环境下的微光系统作用距离的提高。完成的两种焦距分别为250mm和320mm,采用了三代像增强器的夜视仪.野外试验表明,实现对空目标作用距离最大13.7km~18.3km发现、8.0km~8.1km识别。     

微光夜视仪分辨力客观测量方法研究

利用灰度 梯度共生矩阵模型对微光夜视仪分辨力测量图像的纹理特征进行了分析 ,通过对大量图像的 5个纹理特征参数的计算 ,结果表明 ,这些参数能对微光夜视仪分辨力测量图像的纹理特征作出有效的客观评价 ,此计算结果与人眼的观察结果具有较好的一致性。     

微光夜视技术的进展与展望

微光夜视技术作为主要为夜战服务的军用光电子高新技术，其在现代高新技术局部战争和夜战中的作用和地位变得更加突出和重要。随着微光夜视技术的快速发展和器件、系统性能水平的不断提高，微光夜视技术在未来高新技术战争和信息化战争中将具有巨大的发展潜力和广阔的应用前景。在对国外超二代、三代和四代微光像增强器技术发展思路、管型特点和关键技术进行深入分析的基础上，介绍了国内外微光夜视技术的发展现状和最新进展。结合我国目前的设备条件、元器件性能和技术水平的现状，对我国微光夜视技术的发展方向和重要的关键技术进行了阐述，提出了自己的一些建议和展望。     

Kernel based color estimation for night vision imagery

Displaying night vision (NV) imagery with colors can largely improve observer's performance of scene recognition and situational awareness comparing to the conventional monochrome representation. However, estimating colors for single-band NV imagery has two challenges: deriving an appropriate color mapping model and extracting sufficient image features required by the model. To address these, a kernel based regression model and a set of multi-scale image features are used here. The proposed method can automatically render single-band NV imagery with natural colors, even when it has abnormal luminance distribution and lacks identifiable details.     

基于机器视觉的微光夜视仪整机检测系统设计

设计并研制了微光夜视仪整机检测系统,采用CCD器件作为被检仪器输出图像的探测接收器,可在微光夜视仪完整状态下对像增强器进行检测。提出微光夜视仪整机状态下像增强器性能的检测参数,并分析了其检测原理与综合测试方法。通过对检测仪的伸缩式结构、光学系统、CCD选型和检测软件算法等部分进行设计,实现了一台检测仪能够对视场中心分辨力、亮度增益、视场亮度均匀性及视场亮度稳定性等多个性能参量的测试。试验结果表明,检测系统的测试误差在3%以内。     

Third-generation sensors for night vision

Third generation sensors are under development to enhance capabilities for target detection and identification, threat warning, and 3D imaging. Distinct programs for both cooled HgCdTe and uncooled microbolometer devices are part of this thrust. This paper will describe the technology for HgCdle two-colour, high-definition imaging sensors and threat warning devices, avalanche photodiode arrays for 3D imaging, and the supporting technology being developed to enhance the readouts that support these devices. Uncooled detector initiatives will also be described to reduce pixel size in conjunction with the production of 480×640 arrays. Finally, efforts are also beginning to move both photon and thermal detectors closer to radiative-limited performance while simultaneously reducing the cooling requirements for photon detectors. The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59571Z (2005).     

基于深度学习的无人车夜视图像语义分割

为了增强无人车对夜视图像的场景理解,在夜间模式下更快更精确地探测和识别周围环境,将深度学习应用于夜视图像的场景语义分割,提出了一种基于卷积-反卷积神经网络的无人车夜视图像语义分割方法。在传统的卷积神经网络中加入反卷积网络,构建卷积-反卷积神经网络,无需手工选取特征。通过像素到像素的学习和训练,得到图像语义分割模型,可直接用该模型预测夜视图像中每个像素所属的场景语义类别,实现无人车夜间行驶时的环境感知。实验结果表明,该方法具有较好的准确性和实时性,平均IU达到68.47。     

直视型微光夜视系统最小可分辨对比度模型

从信号检测和人眼视觉角度出发,研究了直视微光夜视系统综合性能评估理论,推导出直视型微光成像系统的MRC（最小可分辨对比度）模型。该模型将光学传递特性与系统信噪比结合,建立了系统直视微光夜视MRC与目标特性、直视微光夜视仪以及人眼各部分参数之间的数学关系。验证结果表明,由该模型得到的系统极限分辨率相较于系统实际测出的分辨率相对误差为3.08%。     

微光电视成像系统表征方法

 在分析微光电视成像系统的基础上，提出了适用于微光电视成像系统仿真所用的微光场景图像数据的要求及生成方法；针对第二代近贴聚焦系统和第三代像增强系统，建立了微光电视成像系统的能量增益理论模型；引入３维噪声理论模型表征了微光成像系统的噪声；最后，提出了微光电视图像噪声抑制算法的评价方法。仿真结果表明：经微光系统传递后，图像中的高频信息变模糊，加入噪声后，信噪比降低；而经过5帧平均算法后的图像质量明显改善，对比度增加。     

Coloring night vision imagery for depth perception

Depth perception for night vision （NV） imagery could largely improve scene comprehension. We present a novel scheme to give fused multi-band NV imagery smoothly natural color appearance as well as depth sense from color. Our approach is based on simulating color cues by varying saturation values of each object in the color NV image, in correspondence with the ratio between the infrared and low-light-level sensor outputs which in practice is the depth feature for same materials. We render the NV image segment- by-segment by taking advantage image fusion. Experiments have of image segmentation, dominant shown that the proposed scheme color transfer, saturation variation, and can achieve satisfying results.     

微光夜视系统光晕效应定量表征与建模方法北大核心CSCD

研究了微光夜视系统输出图像中光晕尺寸和灰度分布与系统参数之间的关系,建立了系统光晕效应的定量化表征模型。首先分析了系统输出图像中光晕的产生机理;其次依据微光夜视系统成像原理,通过分析光电阴极产生的光电子数及初角度分布、光电子在光电阴极与微通道板之间的运动、光电子与微通道板非开口壁碰撞后的运动规律及微光成像系统各环节对能量的逐级传递,研究了光晕的定量化表征方法;结合上述理论研究,建立了光晕的数字仿真模型。结果表明:所提出的光晕效应表征模型能够与实验结果中光晕的灰度分布及尺寸较好地吻合;随着强光源能量增大,系统光晕效应越明显,光晕效应对系统成像质量影响越大。     

水下目标噪声测量中的同步钟测距

本测距系统采用两只型号相同的ＷＺＧ－５ＭＨｚ石英晶体振荡器，在同一个时基标准下进行同步测距，５ＭＨｚ石英晶体振荡器具有准确度高，稳定性好的特点，从而成功的解决了在舰船辐射噪声测量中，目标船与测量水听器间测距误差大的问题。本文较详细的介绍了同步钟测距原理，并对在舰船辐射噪声测量中噪声级与距离关系，目标船相对测量水听器的位置，测距误差等进行了描述。     

微光彩色夜视光学系统设计与像质评价

为了充分利用可见光和长波红外所蕴含的不同信息进行数据融合、彩色显示,分析了3种不同类型双波段光学系统及其成像性能,设计了全折射光学系统、折反射光学系统和离轴三反射双谱光学系统。采用不同的分光形式,反射可见光波段,透射长波红外波段,使3种不同类型光学系统的全视场角和相对孔径分别为5°和1∶1.7;光学系统在可见光波段成像质量对应的空间频率50 lp/mm处的MTF=0.60,在长波红外波段成像质量对应的空间频率15 lp/mm处的MTF=0.30。对不同结构类型的系统特点进行分析和讨论,给出了各种像差曲线和光学传递函数曲线,为多波段彩色夜视设计了不同类型的光学系统。     

Renormalized perturbation theory for a multiplicative noise system

We study an anharmonic overdamped oscillator driven by both additive and multiplicative Gaussian white noise. Within the Martin-Siggia-Rose formalism we employ renormalized perturbation theory to calculate the stationary correlation function and the response function of the oscillator variable. Due to the absence of a simple fluctuation-dissipation theorem renormalization cannot make use of exact stationary moments, but is perormed with the help of renormalization conditions.     

基于神经网络的视觉系统标定方法

为了解决摄像机标定存在的若干问题 ,根据立体视觉原理 ,提出了基于神经网络的双目视觉系统标定方法。通过对双目摄像机的有效视场分析 ,确定了一次测量面积 ,并把像对视差作为网络输入 ,建立空间点世界坐标与图像坐标非线性映射关系 ,使系统不经过复杂的摄像机内外参数标定 ,就能直接提取物体的三维信息 ,增加了系统的灵活性。实验证明 ,该方法有效可行     

Effective contrast enhancement method for color night vision

Image fusion refers to the techniques that integrate complementary information from multiple image sensors’ data in a way that makes the new images more suitable for human visual perception. The paper focuses on the low color contrast problem of linear fusion algorithms with color transfer method. Firstly, the contrast of infrared and visible images is enhanced using local histogram equalization and median filter. Then the two enhanced images are fused into the three components of a Lab image in terms of a simple linear fusion strategy. To enhance the color contrast between the target and the background, the scaling factor is introduced into the transferring equation in the b channel. Experimental results based on three different data sets show that the hot and cold targets are all popped out with intense colors while the background details present natural color appearance. Target detection experiments through target recognition area, detection rate, target-background discrimination also show that the presented method has a better performance than the former methods.     

基于微光像增强器的偏振成像系统设计与实验

为验证用微光像增强器实现偏振成像的可行性,根据偏振成像原理,设计了基于分时型偏振成像技术的微光偏振检偏器。选用三代像增强器和高动态范围数字CCD,设计了相应大口径成像物镜和中继光学耦合透镜,获得了高透过率、高调制函数（MTF）的图像耦合性能。采用数字CCD、数字图像采集卡,编写了相应图像处理软件,实现了实验室和野外微光条件下的人造目标和自然景物的偏振探测成像。结果表明,原始图像中目标与背景对比度之比为1.35,基于微光像增强器的偏振成像系统的目标与背景对比度之比为2.35,微光偏振成像能够提高夜间环境下人造目标和自然背景的对比度。     

Fast color contrast enhancement method for color night vision

The increasing availability and deployment of imaging sensors operating in multiple spectral bands has led to a large research effort in color image fusion, resulting in a plethora of pixel-level image fusion algorithms. In this study a simple and fast fusion approach for color night vision is presented. The contrast of infrared and visible images is adjusted by local histogram equalization. Then the two enhanced images are fused into the three components of a Lab image in terms of a simple linear fusion strategy. To obtain false color images possessing a natural day-time color appearance, this paper adopts an approach which transfers color from the reference to the fused images in a simplified Lab space. To enhance the contrast between the target and the background, a stretch factor is introduced into the transferring equation in the b channel. Experimental results based on three different data sets show that the hot targets are popped out with intense colors while the background details present natural color appearance. Target detection experiments also show that the presented method has a better performance than the former methods, owing to the target recognition area, detection rate, color distance and running time.     

Spatial adaptive regularized MAP reconstruction for LD-based night vision

Target recognition plays a vital role in video surveillance, land and ocean exploration, in which imaging detection especially night vision is widely used. It is known that imagery detection is affected not only by absorption and scattering properties of atmosphere or water, but also the optical systems including lenses and sensors. In order to enhance the visual quality of the night vision detecting images to a best possible level, applications such as restoration and super-resolution reconstruction can be applied. The presented effort applies a spatial adaptive regularized MAP reconstruction method to a night vision laser diode (LD) imaging detection system. Blind, objective image quality metrics are adopted for determining the iteration time. Experimental results of the target recognition show adequate improvement in the detecting range as well as the detecting quality provided by the proposed approaches.     

CCD在微光夜视瞄准镜检测系统中的应用

多环境试验条件下的微光枪瞄检测技术一直是军备生产所关注的问题。由于在振动、射击、冲击、跌落和高低温环境等载荷作用下，微光枪瞄机械、光学和电性能结构及参数会发生改变，致使微光枪瞄不能正常工作和使用，所以设计了多环境试验条件下的微光枪瞄检测与测试系统。对测试系统的光路进行了规划，即对被检查对象（微光枪瞄）的安装要求是微光枪瞄的物镜应置于平行光管出射光口的“较近处”。给出了由CCD组成检测系统的工作原理，分析了系统成像的详细过程。通过对平行光管和CCD变焦镜焦距计算，并结合实际工程应用，使该检测系统的测量精度（≤0.05密位）和测量范围（≥40密位）均满足了项目使用要求。