双波段共口径连续变焦光学系统设计

为了解决反射式共口径光学系统装调难度大,存在中心遮拦,能量利用率低的问题,采用折射式共口径、分光板分光的方式,设计了一款双波段共口径连续变焦的光学系统。可见光系统实现了10倍变焦,中波红外系统实现了3倍变焦。采用光学被动式对光学系统进行了消热差处理,并基于约翰逊准则和最小可分辨温差(MRTD)模型分析了可见光系统与中波红外系统的探测距离。设计结果表明,在-40～+60℃的工作环境中,经过消热差处理,可见光系统各组态调制传递函数值在截止频率145 lp·mm^-1处均大于0.28,最大视场可以达到26.4°;中波红外系统各组态调制传递函数值在截止频率31 lp·mm^-1处均大于0.3,最大视场可达到22.6°;运用多点拟合法得到系统的变焦曲线,变焦曲线平滑无拐点,满足双波段共口径连续变焦系统的成像质量要求。     

制冷红外双波段变焦光学系统设计

设计了一组制冷型红外双波段变焦系统,焦距在80～240 mm内变化,视场角1.4°～4.4°,F数为2.2。系统利用二次成像方式,达到了100%冷光阑效率,并采用共光路成像方式同时实现对中长波段的像差校正。设计结果表明:系统满足了3.7～4.8μm中波波段及7.7～10.3μm长波波段同时成像的要求。各视场MTF在17 lp/mm处均接近系统衍射极限,弥散斑均方根半径基本小于一个像元尺寸30μm,成像质量良好。通过机械补偿变焦运动方程计算和Matlab编程绘制出了变焦系统的凸轮曲线,曲线不存在断点,运动过程合理。     

宽波段非制冷红外变焦光学系统设计

面向有毒有害气体探测需求,提出采用双色宽波段高灵敏度红外气体探测方法,并针对宽波段变焦色差校正难题,提出一种基于复消色差和机械正组补偿理论的宽波段红外变焦光学系统设计方法,设计了一种宽波段非制冷红外变焦光学系统。系统焦距25～75 mm,工作波长3～12μm,F数为1.8,适配640×512分辨率的非制冷双色红外焦平面探测器,像素大小17μm,变焦过程中系统总长保持160 mm不变。设计结果表明,系统在全焦段各视场调制传递函数在30 lp/mm处均接近衍射极限,成像质量良好,满足设计要求。系统具有结构紧凑、波段范围宽等优点。     

基于太赫兹波段的三反变焦系统设计

太赫兹波段是指频率从0.1～10 THz,处于微波与红外波段之间.因其具有较强的穿透性、高效抑制背景噪声、良好的时间和空间相干性等特性,故在空间探测应用领域具有很大的潜力.相对透射变焦系统而言,反射变焦系统具有长焦距、大孔径、小体积、利于轻量化设计等优点,故在空间遥感探测领域被广泛使用.因此,设计太赫兹反射式变焦光学系统具有重要的意义和广泛的应用前景.以三级像差理论和矢量像差理论为基础,分别设计了太赫兹波段的共轴三反变焦系统与无遮拦三反变焦系统,焦距范围为300～1200 mm,成像波段为18～35μm,采用RTM-T01非制冷型太赫兹探测器.共轴三反变焦系统的视场角为0.3°～1.2°,系统在10 lp/mm处的MTF≥0.2;无遮拦三反变焦系统的视场角为2° ×2°～0.5° ×0.5°,系统在10 lp/mm处的MTF≥0.3.通过对两种设计结果的比较,可知由于共轴系统反射变焦系统存在遮拦,对增大视场具有局限性,因此,无遮拦反射变焦系统对于空间大视场高分辨探测具有重要应用价值.     

双波段共口径共变焦光学系统设计

为了实现可见、红外两个波段同时观测、跟踪及测量的目的,设计了一款可见/中红外双波段连续共变焦光学系统.系统采用共口径方式同时接收可见、红外两个波段的光波.利用直接变倍比差补偿法对两个波段的变倍比差进行补偿,使可见、红外两个波段变倍比相同且在任一变焦位置焦距相等,满足双波段共口径共光路共变焦的要求.设计结果表明:系统变倍比为12×,焦距范围7~86mm.常温下,可见光工作波段为0.38~0.76μm,其调制传递函数值在空间频率80lp·mm-1处达到0.5以上;中波红外工作波段为3~5μm,其调制传递函数值在空间频率为20lp·mm-1处达到0.6以上.总体积小于392mm×58mm,成像质量满足设计要求.     

非制冷型红外双波段连续变焦光学系统设计

为了满足同步观测、跟踪,同时探测红外中/长波两个波段信息的目标,文中采用共口径方式将红外中/长双波段融合到同一个光路中,设计了一款非制冷型大变倍比红外双波段连续变焦光学系统,引入衍射面和偶次非球面,进行像差校正,选择机械负组补偿方式进行变焦.通过光学被动式消热差方式,匹配材料及分配透镜光焦度,对双波段红外光学系统在-40~+60℃温度范围内进行了消热差设计,并对系统的像质进行了分析.研究结果表明:在不同温度,系统在两个波段下,各个视场内调制传递函数在奈奎斯特频率为20lp·mm~(-1)处均接近衍射极限,系统整体无温度离焦,像面稳定,像质良好,结构紧凑,满足使用要求.     

可见光/红外双波段大视场共口径齐焦光学系统

针对双波段系统光路转换速度慢、不同波段目标信息存在差异的问题,文中结合可见光和长波红外两个波段的特点,设计了可见光/长波红外大视场共口径齐焦光学系统.采用共口径方式同时接收可见光/长波红外两个波段的目标信息,通过齐焦设计提高不同波段目标信息的一致性.研究结果表明:可见光工作波段为0.38~0.76μm,长波红外工作波段为7.9~9.7μm,两个波段视场为70°,焦距为6.1mm.可见光传函值在空间频率100lp/mm处在0.4以上,长波红外传函值在空间频率20lp/mm处接近0.4,在-40~60℃的温度范围进行消热差.     

基于目标探测光学补偿红外变焦系统设计

为提高联合变换相关器的探测能力,针对2/3英寸红外CCD探测器,设计了一种红外光学补偿变焦系统,应用于联合变换相关器的红外目标探测。该系统在焦距100-200mm内连续变焦,工作波段为8-12μm,F数为3。系统仅由7片透镜组成,引入两个非球面。像质评价结果表明：在整个变焦范围内,在截止频率17lp/mm时,各视场MTF接近衍射受限曲线,像质优良、像面稳定,满足光学系统的总体设计要求。     

双波段昼夜大视场光学系统设计与实现

针对多层次伪装手段及不同波段下目标的不同细节的情况,结合可见光和中红外两个波段的特点,设计了可见光和中波红外大视场光学系统.采用共口径形式,可同时接收两个波段的信息,对红外系统在-40~+60℃选用光学被动式消热差.研究结果表明:在视场均为92°下,可见光传递函数在空间频率100lp·mm-1处高于0.35,中波红外传递函数在空间频率20lp·mm-1处达到0.47.整个系统组合体积小,可实现昼夜全天候工作.     

基于双波段共口径的弹着点位置检测光学系统设计

针对远距离大范围复杂环境下弹着点目标的探测识别受限问题,设计了一款双波段共口径连续变焦光学系统.选择折射式光学系统,采用共口径、棱镜分光设计方法,可见/长波红外双波段系统共用同一入射窗口,通过棱镜分光,实现可见光与长波红外同时成像.光学系统在0.38～0.76μm波段内实现18～180 mm的10×连续变焦,在8～14...     

Three-dimensional temperature reconstruction of diffusion flame from the light-field convolution imaging by the focused plenoptic camera

The plenoptic imaging technique provides a promising approach to the non-invasive three-dimensional measurement, especially for the high-temperature combustion diagnosis. We establish a light-field convolution imaging model for diffusion flame in this work, considering the radiation transfer process inside the diffusion flame and the light transfer process inside the focused plenoptic camera together. The radiation transfer process is described by the radiation transfer equation and solved by the generalized source multi-flux method. Wave optics theory is adopted to describe the light transfer process, combining Fresnel diffraction and the phase conversion of the lens. The flame light-field image is obtained by the light-field convolution imaging model and adopted as the measurement signal to reconstruct three-dimensional temperature field. The inverse problem of temperature reconstruction is solved by the least square QR decomposition method. The simulative temperature reconstruction work is conducted, including the inverse analysis, the uncertainty analysis, and the measurement noise influence. All the results show that the proposed measurement method is available to reconstruct three-dimensional temperature with satisfactory accuracy and acceptable uncertainty. Both symmetric and asymmetric distributed temperature fields are investigated, and the reconstructed results prove the validity and universality of the measurement method.

     

变焦电子腹腔镜物镜光学系统的设计

医用内窥镜在现代医学中的应用越来越广泛,为了使医生在临床检查的时候能够更好的观察病灶图像,设计一种可以实现变焦的电子腹腔镜物镜的光学系统,可以对病灶图像进行原位放大观察。以高斯变焦公式为基础,利用ZEMAX软件模拟设计了一个变焦物镜的光学系统,当视场范围在24°~64°,焦距在5mm~15mm三倍变焦,成像大小保持在6mm左右。传递函数设定在40线对时,其传递函数(MTF)要满足≥0.6,点列图弥散斑直径≤0.05mm。设计具有大视场,镜片数少,结构简单等特点,可以对病灶图像进行放大,具有较高的实际应用价值。     

Research on a New-style Visual Sensor for Measurement

First,the constitution of traditional visual sensor is presented.The linear camera model is introduced and the transform matrix between the image coordinate system and the world coordinate system is established.The basic principle of camera calibration is expatiated based on the linear camera model. On the basis of a detailed analysis of camera model,a new-style visual sensor for measurement is advanced.It can realize the real time control of the zoom of camera lens by step motor according to the size of objects.Moreover,re-calibration could be avoided and the transform matrix can be acquired by calculating,which can greatly simplify camera calibration process and save the time. Clearer images are gained,so the measurement system precision could be greatly improved.The basic structure of the visual sensor zoom is introduced,including the constitute mode and the movement rule of the fixed former part,zoom part,compensatory part and the fixed latter port.The realization method of zoom controlled by step motor is introduced. Finally,the constitution of the new-style visual sensor is introduced,including hardware and software.The hardware system is composed by manual zoom,CCD camera,image card,gearing,step motor,step motor driver and computer.The realization of software is introduced,including the composed module of software and the workflow of measurement system in the form of structured block diagram.     

Research on a New-style Visual Sensor for Measurement

First, the constitution of traditional visual sensor is presented. The linear camera model is introduced and the transform matrix between the image coordinate system and the world coordinate system is established. The basic principle of camera calibration is expatiated based on the linear camera model.On the basis of a detailed analysis of camera model, a new-style visual sensor for measurement is advanced. It can realize the real time control of the zoom of camera lens by step motor according to the size of objects.Moreover, re-calibration could be avoided and the transform matrix can be acquired by calculating, which can greatly simplify camera calibration process and save the time. Clearer images are gained, so the measurement system precision could be greatly improved. The basic structure of the visual sensor zoom is introduced, including the constitute mode and the movement rule of the fixed former part, zoom part, compensatory part and the fixed latter part. The realization method of zoom controlled by step motor is introduced.Finally, the constitution of the new-style visual sensor is introduced, including hardware and software. The hardware system is composed by manual zoom, CCD camera, image card, gearing, step motor, step motor driver and computer. The realization of software is introduced, including the composed module of software and the workflow of measurement system in the form of structured block diagram.     

折衍混合长波红外摄远物镜设计

红外光学系统具有可全天候工作、远距离观察等优势,在军事及民用领域均得到广泛应用。但由于温度对红外系统影响较大,所以需要对其进行消热差设计。依据消热差及色差原理选择适合的透镜材料,利用衍射元件的消热差和色差的特性,设计了波段为8~12μm,全视场为2ω=6°,焦距为 f=100mm , F数为2,温度补偿范围-40℃~60℃的长波红外折衍混合摄远物镜。使用保罗I棱镜来折叠光路,使系统结构紧凑,摄远比达到了0.8。该系统在-40℃~60℃范围内,调制传递函数（MTF）优于0.5,接近衍射极限,成像质量良好。     

红外变焦系统结构设计

为了模拟目标成像大小的变化过程,设计了一款17x的红外变焦系统,为保证系统在变焦过程中像面的稳定性,应用动态光学知识在Matlab中建立数学模型,得到变焦拟合曲线。重点针对变焦系统的结构进行了设计与分析,由物理制约条件出发分析了凸轮直径、工作转角及螺旋升角间的关系。实验表明,基于动态光学设计的凸轮曲线可以保证系统在变焦过程中像面稳定,成像质量良好。     

基于双直线电机的光学镜头连续变焦控制

针对传统变焦距系统存在响应速度慢、定位精度差和视轴晃动大等问题,设计了一种新型的连续调焦组件及其控制系统。利用双混合直线步进电机和微型光栅尺构成调焦组件,在简化变焦结构的基础上,采用一种四组式机械补偿方法对光学镜进行连续变焦距控制,设计了相应的变焦控制算法和控制系统硬件电路。外场实验结果表明,该系统在定位精度、响应精度和视轴晃动等方面较传统变焦控制系统均有明显改善,定位误差小于1%,视轴晃动小于10″。     

工业炉气体吸收系数检测的模拟研究

对均质和非均质工况下工业炉气体吸收系数的检测进行研究,提出基于可见光图像处理技术的气体吸收系数重建算法。采用电荷耦合器（CCD）接受边界辐射强度图像和辐射温度图像,从辐射强度图像中更新辐射参数,用正则化方法从辐射温度图像中重建介质温度场,两者交替迭代,直至收敛。模拟计算结果表明,在测量数据中加入标准差为0.05的正态分布误差后,采用该算法仍然可以较好地重建出炉内气体的吸收系数。     

折射式红外变焦光学系统内部杂光分析

针对折射式红外变焦光学系统内部的杂散辐射,设计了焦距240-60mm、系统F/#为4、视场11.96°-2.84°、工作波段为3.7-4.8μm的制冷型中波红外变焦光学系统。该系统为二次成像结构,并且有100%的冷光阑效率。利用杂散光分析软件Light Tools,建立光学机械结构模型并判断出关键表面,分析得到探测器像面接受的热辐射,根据信噪比推断出目标的最小辐亮度。采用光路倒置的方式分析光路中各光学表面产生的冷反射大小,分析了光学系统在不同焦距时的冷反射效应,结果表明该光学系统具有较好冷反射抑制效果。     

Analytical prediction and field validation of transient temperature field in asphalt pavements

This work presented the development and validation of an analytical method to predict the transient temperature field in the asphalt pavement.The governing equation for heat transfer was based on heat conduction radiation and convection.An innovative time-dependent function was proposed to predict the pavement surface temperature with solar radiation and air temperature using dimensional analysis in order to simplify the complex heat exchange on the pavement surface.The parameters for the time-dependent pavement surface temperature function were obtained through the regression analysis of field measurement data.Assuming that the initial pavement temperature distribution was linear and the influence of the base course materials on the temperature of the upper asphalt layers was negligible,a close-form analytical solution of the temperature in asphalt layers was derived using Green's function.Finally,two numerical examples were presented to validate the model solutions with field temperature measurements.Analysis results show that the solution accuracy is in agreement with field data and the relative errors at a shallower depth are greater than those at a deeper one.Although the model is not sensitive to dramatic changes in climatic factors near the pavement surface,it is applicable for predicting pavement temperature field in cloudless days.