Stereoscopic video surveillance system for detection of target’s 3D location coordinates and moving trajectories

In this paper, a novel stereoscopic video surveillance system to track a target person and detect its three-dimensional (3D) location coordinates and moving trajectory is implemented by using the pan/tilt-controlled stereo camera system. Stereoscopic video images of a target person are captured with stereo camera system and the target face and its location in the left image plane can be detected by use of YCbCr color model and centroid method. Also the target location in the right image plane can be obtained through correlation between the left face image and the right image by using the binary phase extraction joint transform correlator (BPEJTC) algorithm. With these location data of the target face in the left and right image planes the pan/tilt systems can control the stereo camera to track a target person by positioning the target face at the center of the camera’s FOV and making the focusing points of the right and left camera coincided on the target face. And then, with the resultant pan/tilt angles and geometric parameters of the stereo camera system, the target’s real 3D location coordinates and moving trajectory in the world space can be obtained. From some experiments with 900 frames of stereoscopic video image pairs, it is analyzed that the target’s center location after being tracked is kept to be very low error ratio of 0.62%, 2.04% on the average in the x, y directions of the image plane, respectively. Also, the error ratio between the calculated and measured values of the 3D location coordinates of a target person is found to be very low value of 2.1%, 5.7% on the average in the X and Y directions of the real world space, respectively.     

弹道相机白天工作能力的影响因素分析及提高途径

弹道相机通常是在夜间对飞行目标进行拍摄,在相机类型不改变的情况下要达到白天工作能力具有一定困难,主要障碍是拍摄后,底板上目标与背景的衬比(度)下降,难以达到判读要求.针对这一问题,本文详细叙述了各因素对判读要求的影响,提出了改善相机白天工作能力的可行方法.     

内增强变象管相机中的干扰研究

本文讨论了带快门的内增强变象管相机的快门电路及其对扫描电路的干扰,干扰信号对相机性能指标的影响及解决方法。     

同步相机测量任意频率光信号时的S/N理论分析

本文从理论上分析了同步扫描相机在测量由双波长激光器产生的差频信号时信噪比的问题.这一差频信号的频率和同步相机的扫描频率并非整数倍关系.我们从光电阴极的发射噪音(shotnoise)理论出发,得出了在这种特殊应用情况下相机的信嗓比比正常应用情况下(即入射光脉冲的频率和扫描频率为整数倍关系)至少要小23倍.     

毛细管放电X光激光装置中的预脉冲电源

针对目前毛细管放电X 光激光装置产生的预脉冲电流幅值过大、持续时间较短的问题，提出了增加预脉冲开关抑制原有预脉冲，再外加由脉冲成形网络组成的预脉冲发生器，产生所需预脉冲的改造方案。可在主脉冲来临之前产生幅度10~50A，持续时间约17μs的方波预脉冲电流，来满足毛细管放电泵浦类氖氩X光激光实验的需要。     

Submillimeter imaging with a pyroelectric TV camera

The use of a TV camera with a standard pyroelectric tube for imaging continuous submillimeter (submm) waves is described. The spectral sensitivity of such pyroelectric vidicon has been measured. The results of experiments on diffraction and interference using submm laser radiation are presented. For the first time, submm images of different objects have been obtained with the aid of a pyroelectric vidicon. It has been shown that a pyroelectric TV camera can be effectively employed in various laser studies as well as in submm imagery technique.     

使用多个线阵CCD-计算机系统实时监控多界面位置

本文提出一套多界面位置实时监控系统。该系统采用八个线阵ＣＣＤ像感器分别接收每个界面的光学图像。按照控制程序的设定，适时点亮界面的照明光源，同时驱动ＣＣＤ开始工作，并在采集完界面位置信息后，关掉照明光源及ＣＣＤ，以延长系统的寿命，实现长期连续工作。为了同时分别监控多个界面，设计了专用微机接口电路，通过硬件电路实现各界面数据的同时锁存，然后将每个ＣＣＤ的光电信号采入计算机，解决了目视读数无法保证多处数据在时间上一致性的困扰。运用该系统监控多处油水界面，每处均可在１００ｍＬ体积的检测管内测量到０．１ｍＬ的界面变化。     

真空紫外/可见光纳秒条纹相机的研制

ZNT-500K真空紫外/可见光纳秒条纹相机已研制成功,在研制过程中,研制了新型变象管,较好地解决了MgF²晶体和科伐材料的高真空封接,合理地确定了导电基底的材料和厚度,使光谱响应和透过率都满足要求;合理地确定扫描电路和电路参数,使该相机具有了光谱响应范围宽和扫描时间范围宽两大特点。     

五孔剪切相机在测量二阶微分场中的应用

提出了在使用五孔剪切相机研制二阶微分场时，通过采用两次全场滤波技术可消除夹在二阶微分条纹中的一阶微分条纹，从而使二阶微分条纹具有较高对比度。     

激光空泡刚性半球面内运动

采用甚高速照相技术与建立激光空泡在刚性半球壁面内的运动模型相结合的方法,确定了激光空泡在刚性半球面壁内的运动特性与无量纲距离的关系,提出了最佳无量纲距离概念。结果表明:半球反射面的半径与激光空泡最大半径之比小于1.1时,激光空泡在第1次膨胀时就会产生严重的变形并弹出半球面,并产生空化泡和空蚀,它们均会严重影响激光声的传播。该比值在1.1~3.3时,激光空泡将在第3次收缩之前接触半球面,容易对壁面造成空蚀。在该比值大于3.3的情况下,激光空泡在第3次收缩之前不会接触半球面,对激光声的传播和反射特性影响较小。如果考虑把空泡第1次溃灭时产生的激光声的声学中心控制在击穿点时,需要把该比值控制在5以上。