高速转镜相机中倾斜光束的成象

本文通过建立几何模型 ,讨论了高速转镜相机光束倾斜入口的成象原理。证实了倾斜光束入口在转镜旋转时成象点的扫描轨迹是在以入射点为顶点 ,以成象点和入射点的连线为母线扫出的正圆锥底面的平面内 ,从而把空间光学的复杂设计问题简化成平面上的设计。此原理已用于 PDF- 2 0 0型平面转镜等待式分幅相机的设计     

自适应路网拥堵疏导系统的研究

随着汽车工业的飞速发展,路网建设显得相对滞后,大中城市中交通拥堵日益严重.介绍一种基于有限状态机的自适应路网拥堵疏导系统,它由路口车流量信息的获取和红绿灯时间自动设置两部分组成.借助数字城市中的视频监控设施,获取路口实时的交通流量信息;再通过基于有限状态机的控制系统,实现红绿灯导通时间的自主设置,前瞻性地缓解路网拥堵现象.     

Automatic camera control in virtual environments augmented using multiple sparse videos

Automated virtual camera control has been widely used in animation and interactive virtual environments. We have developed a multiple sparse camera based free view video system prototype that allows users to control the position and orientation of a virtual camera, enabling the observation of a real scene in three dimensions (3D) from any desired viewpoint. Automatic camera control can be activated to follow selected objects by the user. Our method combines a simple geometric model of the scene composed of planes (virtual environment), augmented with visual information from the cameras and pre-computed tracking information of moving targets to generate novel perspective corrected 3D views of the virtual camera and moving objects. To achieve real-time rendering performance, view-dependent textured mapped billboards are used to render the moving objects at their correct locations and foreground masks are used to remove the moving objects from the projected video streams. The current prototype runs on a PC with a common graphics card and can generate virtual 2D views from three cameras of resolution 768×576 with several moving objects at about 11 fps.     

Detection algorithm for color dynamic images by multiple surveillance cameras under low luminance conditions based on fuzzy corresponding map

An objects detection algorithm for color dynamic images from two cameras is proposed for a surveillance system under low illumination. It provides automatic calculation of a fuzzy corresponding map and color similarity for lower luminance conditions, which detects little chromatic regions in CCD camera images under lower illumination and presents regions with a possibility of occlusion situation. Experimental detection results for two dynamic images from real surveillance cameras in a downtown area in Japan under low luminance conditions show that the proposed algorithm has 15% improved accuracy compared with the independent detection algorithm in the same false alarm rate, which occlusion regions are correctly presented. Moreover, implementability for severe surveillance situation is discussed. The proposed algorithm is being considered for use in a low cost surveillance system at a relatively poor security downtown (shopping mall) area in Japan.     

Real-time predictive zoom tracking for digital still cameras

Zoom tracking is becoming a standard feature in digital still cameras (DSCs). It involves keeping an object of interest in focus during the zooming-in or zooming-out operation. Zoom tracking is normally achieved by moving the focus motor in real-time according to the so-called trace curves in response to changes in the zoom motor position. A trace curve denotes in-focus motor positions versus zoom motor positions for a specific object distance. A zoom tracking approach is characterized by the way these trace curves are estimated and followed. In this paper, a new zoom tracking approach, named predictive zoom tracking (PZT), is introduced based on two prediction models: auto-regressive and recurrent neural network. The performance of this approach is compared with the existing zoom tracking approaches commonly used in DSCs. The real-time implementation results obtained on an actual digital camera platform indicate that the developed PZT approach not only achieves higher tracking accuracies but also effectively addresses the key challenge of zoom tracking, namely the one-to-many mapping problem.

Visual understanding industrial workflows under uncertainty on distributed service oriented architectures

Service Oriented Architecture (SOA) is an evolution of distributed computing based on the request/reply design paradigm for synchronous and asynchronous applications. In such architectures, application developers or system integrators can build scenarios by composing one or more services without knowing the services’ underlying implementations. In this paper, we adopt a SOA framework for on-line scheduling complex industrial workflows. The proposed SOA consists of three main layers; the input layer, the benchmarking layer, the prediction layer and the scheduler. The main innovation of our SOA architecture is the prediction layer that supports computer vision tools able to visually observe how an industrial workflow is actually executed. This way, we can automatically estimate the actual execution time for a process. In particular a new self-initialized visual tracker algorithm is proposed in this paper to robustly trace workers’ trajectory in a plant via visual observations. Then, part-to-whole curve matching is presented so as to find correspondences among the traced curve and the ideal one and thus improving scheduler efficiency. The input layer interoperably describes industrial operations using the XPDL (an XML-based) format. The benchmarker evaluates much faster than real-time and in an off-line mode how long it takes for an industrial workflow to be executed on a given resource guaranteeing an almost real-time implementation of the video processing algorithms on the plant. The last component of the proposed SOA is the scheduler with the goal to assign the workflows to the available resources. In this paper, a Maximum Benefit First (MBF) scheduler is presented which maximizes the total gain received by the industry when completing execution of all the beneficial operations with minimum violations of their delivery deadlines (that is with the minimum compensations). Experiments have been conducted on a real-world industrial plant of Nissan Iberica automobile construction indicating the efficiency of the proposed system.     

基于投影特征点的多摄像机标定方法

针对标定物存在的自遮挡问题,提出了一种应用于多摄像机的利用投影特征点进行标定的方法。在投影平面幕中投影标定图案,统一投影平面坐标系与世界坐标系。特征提取后,分别对每个摄像机标定,根据立体视觉特性求取摄像机间的相对位姿关系,并计算重投影误差。该方法对标定物自遮挡有一定的鲁棒性,同时有效地降低了计算量。     

堆芯摄像中的双视场合成原理及设计

为了实现两个不同方位的目标在同一视场中成像,通过反射镜将摄像机视场分成两个部分,这样光程相等的两目标便能在同一视场中成像。在堆芯摄像中,根据这一原理设计了具体的光学结构,并对光路进行了具体分析,同时对实际使用中的标识符进行了验算,表明该设计是合理的。     

变焦遗传算法优化变增益模糊ARX模型研究

针对传统ARX模型对非线性系统模型辨识精度比较低的问题,进行了模糊模型和ARX模型相关优化算法的调查,介绍了遗传算法优化模糊模型的现状,提出采用改进变焦遗传算法优化变增益模糊ARX模型参数的方法以提高模型的辨识精度。改进的变焦遗传算法能在不同前代种群情况下更新不同数量基因,以提高搜索速度;用不同的概率选择交叉位置,可避免早熟现象,并能在较短时间内达到最优或次优解。变增益模糊ARX模型可根据非线性系统的变化改变其增益,使模型的辨识精度提高。利用改进变焦遗传算法的优点,对变增益模糊ARX模型的参数进行优化,并通过两入两出多时滞离散非线性系统进行试验仿真。试验结果证明了改进变焦遗传算法优化变增益模糊ARX模型参数的方法能提高模型辨识精度,表明了提出的优化方法的有效性,为变焦遗传算法与模糊模型的结合提供了一种途径。     

应用多个正交视角轮流逼近3维目标的坐标

为实现目标的快速、精确3维定位和跟踪,提出一种正交摄像机视频定位系统及其坐标轮流逼近的迭代定位算法。系统中平面摄像机光轴按照正交方式布置,拍摄方向均指向原点。不同于现有的大部分计算机视觉方法,本算法中没有影响定位效率和精度问题的图像配准操作。证明了迭代算法的收敛性。数值验证和实际试验表明,本算法计算简单、误差稳定性好,收敛快,因此具有良好的应用潜力。