A cooperative camera surveillance method based on the principle of coarse-fine coupling boresight adjustment

Visual surveillance systems play a vital role in smart manufacturing scenes. In this paper, a cooperative camera surveillance method is proposed based on the coarse-fine coupling boresight adjustment principle. A master-slave camera cooperative monitoring model is established by combining a high-resolution camera with a large-field camera, the former of which is embedded with a Risley prism pair to perform high-precision boresight pointing for monitoring a local target, while the latter can observe a wide scene and guide the former to catch a region of interest. An effective boresight adjustment strategy is put forward with a method of combining fast convergence and iterative refinement. A calibration method of the master-slave camera is proposed with the combination of binocular vision and equivalent motion plane. The error distribution, adjustment efficiency and tracking accuracy of the dual field monitoring are analyzed in detail to reveal the mapping mechanism between imaging feedback and boresight adjustment. In the surveillance experiment, the root-mean-square tracking error of the fine tracking camera can achieve better than 7.04 pixels, while the adjustment steps only need about 10 times, which validates the feasibility and effectiveness of the proposed method in industrial operation surveillance.     

Nomarski偏振光干涉仪与短脉冲相干光源

通过详细计算给出用超短光脉冲作相干光源的偏振光干涉仪中Ｗｏｌｌａｓｔｏｎ棱镜的设计参数，并仔细分析了棱镜在光路中处于不同位置时对干涉仪性能的影响。     

Finite layer and triangular prism element method to subsidence prediction and stress analysis in underground mining

Introduction　　Groundsubsidenceduetoundergroundcoalminingmaycausedamagetosurfacestructuresandfarmlandandchangesurfaceandsurfacedrainagepatters.Duringthepastfewdecades ,anumberofsubsidencepredictiontechniqueshavebeenproposed .Currently ,theinfluencefunctionmethodisthemostwidelyusedforpredictionoflong wallcoalminingsubsidence .Butthesemethodscanbeonlyusedtocalculatethegroundsubsidence .Theycannotbeusedtoanalyzestressofminingimpactstratum .Finiteelementmethodmaybeusedtocalculatethestressanddisp…     

小型飞秒激光脉冲放大器

在放大器谐振腔内插入一对棱镜,使飞秒脉冲信号边放大,边展宽。既防止了强光的自聚焦效应,又减小了整个放大器占用空间。输出光再经过另一对棱镜压缩,得到的脉宽小于100fs,重复率10kHz,平均功率达到0.2W。     

利用坐标变换求Wollaston棱镜的分束角

利用光的折射定律和坐标变换对Wollaston棱镜的分束角随任意入射角变化关系进行了理论分析。对在不同的入射面内分束角分别随入射角的变化,对在方位角为0的入射面内分束角随结构角的变化做了详细分析并进行了实验测试,新公式得到的理论结果与实验相符合。     

Simulation on damage effectiveness of hexagonal prism aimable warhead with multi-point synchronous initiations

In order to study the impacts of warhead geometry and initiation pattern on the lethality of aimable warhead,multi-point synchronous initiated hexagonal prism and cylindrical warheads were compared through numerical simulation,combined with theoretical formulas of fragment deceleration and target plugging.Enhancements of fragment velocity,kinetic energy and density toward the target and target destructions were analyzed.The results show that hexagonal prism warhead can produce dense fragment beams and enhance average velocity and kinetic energy with asymmetric eight-point initiation by 24.13% and54.52%respectively,which are higher than those of the isometric or same weight cylindrical warhead.The effective fragments are still relatively concentrated in an area of 8m×2mfor the hexagonal prism warhead when the distance between warhead and target is 40m.     

RGB converter based on liquid prism

In this paper, we propose a Red Green Blue (RGB) converter, which is an expanded application of electrowetting liquid prism in the micro‐systems. Four rectangular indium tin oxide (ITO) glass substrates having the same size are stacked to form the sidewalls. Another ITO electrode is fabricated and stuck on the bottom polymethyl methacrylate substrate as the opposite electrode. With two immiscible fluids in the transparent cell, the shape of the liquid–liquid interface can be deformed by electrostatic force. Three different color filters are placed under the prism. When we apply different voltages, the light beam will propagate through different filters by deforming the liquid–liquid interface. Our results show that we can obtain the light having three different colors from a non‐transparent cap's light hole. The device is capable of reasonable switch time (~75 and ~140 ms). It has a wide potential application in tunable lasers, adaptive indicators, and display systems.     

基于棱镜的多光轴平行性检测研究

反射棱镜是光学仪器中的一种重要光学元件,起着正像、折转光轴、缩小仪器尺寸等作用。反射棱镜的作用是使光轴变成折线,可以在空间折转,所以应有空间概念,从空间角度来研究物体及其像的共轭关系。本文应用动态光学【1】理论,从理论上分析了棱镜的特点,即对于平面非屋脊棱镜,当反射次数为偶数,出射光轴和入射光轴同向时,棱镜旋转像不产生偏转;对于平面屋脊棱镜,当反射次数为奇数,出射光轴与入射光轴反向,棱镜旋转像不产生偏转。根据该特点,将单个不同形式的棱镜或按一定要求将棱镜组合,使其入射光轴与出射光轴满足上述要求,即可将其应用到多光轴平行性检测中,替代大口径平行光管的作用,实现不受光轴口径限制的多光轴平行性的检测。本文列举了几种具有该特点的棱镜,并将其应用到实际多光轴平行性检测中。     

基于水动力数值模拟的罗源湾水体交换周期及纳潮量计算EI北大核心CSCD

为了分析罗源湾水动力特性及流场情况,建立了基于Mike21的罗源湾水动力数学模型,经率定得到模型湾内海域Smagorinsky系数为0.28,糙率为0.024~0.035,风拖曳系数为0.0010~0.0015。利用该模型模拟计算了罗源湾水体交换周期及纳潮量,结果表明:涨落潮时,罗源湾流速在0.20~1.56 m/s,湾口及可门水道水动力条件好,北岸及西北角水动力条件较差,北岸受湾外海域潮波影响程度低于南岸;罗源湾水体半交换周期约为15 d,15 d、30 d、45 d和60 d后罗源湾水体平均交换率分别为48.5%、69.3%、78.8%和85.5%;秋季时罗源湾平均纳潮量为5.73亿m^(3),大潮纳潮量为7.07亿m^(3),小潮纳潮量为4.40亿m^(3)。建议在罗源湾入海污染源通量管控过程中,综合考虑海域自身水动力条件,合理控制罗源湾西北角入海污染物排放量。     

半解析Fourier p型单元棱柱体的自由振动分析

介绍一种用来分析棱柱体自由振动的半解析Fourier p型单元.采用若干三角形函数和一定数量的多项式形函数表述单元的横向位移.多项式形函数描述单元的节点位移,三角形函数为单元边界及内部提供附加的自由度.由于附加的Fourier自由度和缩减的维数,固有频率的计算精度获得很大的提高.分别应用半解析Fourier p型单元,有限棱柱单元,Fourier p型单元,一般线性单元计算一悬臂立方体的固有频率.计算实例表明半解析Fourier p型单元计算结果的收敛速率随三角函数项数的增加而快速收敛,且计算精度也要高于其它方法.