舰船甲板及平台规范校核软件设计研究

利用VB6.0编制了计算甲板及平台局部强度校核的软件,读取由TRIBON软件中导出的XML数据库中的甲板及平台结构数据信息,自动识别判断板格,并进行校核计算.编制的软件界面操作简单,实用性强,其自动生成的强度校核报告能满足使用的要求,从而有效地减轻了设计人员的工作量,具有很强的实际应用价值.     

多波束倾斜安装技术在水下检测工程中的应用

由于常规多波束系统垂直安装,无法精确测量临岸水域、码头、防波堤、丁坝、海岛礁等特殊水下地形地貌。针对这一难题,进行了多波束倾斜安装和校准的技术研究。采用多波束倾斜安装的方法,增加相关侧的波束数量,测量能够达到吃水线位置。水深成果精度满足规范及工程需求,实现了水下特殊地形地貌的全覆盖测量,为水上水下一体化模型提供技术支撑,可以广泛应用在水下检测工程中。     

Calibration of nonlinear car-following laws for traffic oscillation prediction

Frequency-domain analysis has been successfully used to (i) predict the amplification of traffic oscillations along a platoon of vehicles with nonlinear car-following laws and (ii) measure traffic oscillation properties (e.g., periodicity, magnitude) from field data. This paper proposes a new method to calibrate nonlinear car-following laws based on real-world vehicle trajectories, such that oscillation prediction (based on the calibrated car-following laws) and measurement from the same data can be compared and validated. This calibration method, for the first time, takes into account not only the driver’s car-following behavior but also the vehicle trajectory’s time-domain (e.g., location, speed) and frequency-domain properties (e.g., peak oscillation amplitude). We use Newell’s car-following model (1961) as an example and calibrate its parameters based on a penalty-based maximum likelihood estimation procedure. A series of experiments using Next Generation Simulation (NGSIM) data are conducted to illustrate the applicability and performance of the proposed approach. Results show that the calibrated car-following models are able to simultaneously reproduce observed driver behavior, time-domain trajectories, and oscillation propagation along the platoon with reasonable accuracy.     

Multilane first-order traffic flow model with endogenous representation of lane-flow equilibrium

In this study, we develop a multilane first-order traffic flow model for freeway networks. In the model, lane changing is considered as a stochastic behavior that can decrease an individual driver’s disutility or cost, and is represented as dynamics toward the equilibrium of lane-flow distribution along with longitudinal traffic dynamics. The proposed method can be differentiated from those in previous studies because in this study, the motivation of lane changing is explicitly considered and it is treated as a utility defined by the current macroscopic traffic state. In addition, the entire process of lane changing is computed macroscopically by an extension of the kinematic wave theory employing IT principle; moreover, in the model framework, the lane-flow equilibrium curve is endogenously generated because of self-motivated lane changes. Furthermore, the parsimonious representation enables parameter calibration using the data collected from conventional loop detectors. The calibration of the data collected at four different sites, including a sag bottleneck, on the Chugoku expressway in Japan reveals that the proposed method can represent the lane-flow distribution of any observation site with high accuracy, and that the estimated parameters can reasonably explain the multilane traffic dynamics and the bottleneck phenomena uphill of sag sections.     

Specific object re-identification across non-overlapping camera views in traffic accidents

ABSTRACT

To improve the robustness of object re-identification in complex outdoor environments for traffic safety systems, a novel object re-identification algorithm based on the Individual Similarity Difference Feature (ISDF) method is proposed. This method can provide reliable support for specific object tracking during traffic accidents in video surveillance networks. First, all the images in the gallery are divided into three parts according to a segmentation ratio, and six types of feature for each part are extracted. Second, prototypes for each feature of the three parts are constructed. Third, the image sequence of the same person is grouped, and then the ISDF is extracted from each image. Finally, we use the AdaBoost classifier to judge whether the two objects are matched and then output the final results. Extensive experiments are conducted on two public data sets (Eidgenössische Technische Hochschule Zürich and multi-camera object tracking). The performance of the object re-identification method is superior to the latest methods.     

Analysis of the pencil of conics with double complex contact and its application to camera calibration

In this paper,we introduce a novel class of coplanar conies,the pencil of which can doubly contact to calibrate camera and estimate pose.We first analyze the properties of con-axes and con-eccentricity ellipses, which consist of a natural extending pattern of concentric circles.Then the general case that two ellipses have two repeated complex intersection points is presented.This degenerate configuration results in a one-parameter family of homographies which map the planar pattern to its image.Although it is unable to compute the complete homography,an indirect 3-degree polynomial or 5-degree polynomial constraint on intrinsic parameters from one image can also be used for camera calibration and pose estimation under the minimal conditions.Furthermore, this nonlinear problem can be treated as a polynomial optimization problem(POP) and the global optimization solution can be also obtained by using SparsePOP(a sparse semidefinite programming relaxation of POPs). Finally,the experiments with simulated data and real images are shown to verify the correctness and robustness of the proposed technique.     

发动机转速传感器测控平台设计

设计了一种新的发动机转速传感器测控平台。该平台主要包括DSP系统板、磁电式转速传感器、发动机转速工况模拟装置、汽车转速仪表以及上位机。介绍了器件选型及硬件设计过程,分析了汽车仪表转速系数修正与标定、转速信号频率测量及系统测控流程。测试结果表明:该平台人机界面友好,操作简单方便,转速传感器信号测量准确可靠,模拟工况控制快速平稳。     

基于激光摄影测量方法的地铁限界检测系统研究*

限界检测系统主要采用激光摄影测量方法快速实现地铁限界非接触式检测,检测系统采用激光摄像式传感器实时采集隧道断面图像,通过对激光摄像式传感器非线性模型进行标定从而建立空间物体与摄像机图像像素之间映射关系,实现隧道断面上待测目标点的距离测量。针对系统中激光光条图像的处理,先后采用图像预处理算法提高图像处理效率,Sobel算子提取激光光条边缘,利用 Sobel算子提供的光条梯度信息经脊线跟踪法实现光条中心亚像素提取,提高检测系统精度。利用研制出的地铁限界检测系统进行现场试验和精度验证。试验表明,地铁限界检测系统能够满足地铁限界高精度检测需求,能够为地铁安全运行发挥重要作用。     

基于单目机器视觉的船舶测距定位原理研究

利用透视投影几何关系和摄像机内部参数,计算船舶与各陆标之间的距离,提出一种基于单目机器视觉的船舶测距定位方法。仿真结果表明,该方法与传统的陆标定位方法相比,具有简易、实时、受海况影响小的优势,可满足全封闭舰船陆标定位要求。     

SeaBat 8125安装误差校准及在边坡测量中的应用

概述了SeaBat 8125的特点,论证了多波束安装参数校准的作业方法和误差分析,对多波束校准参数的关联性进行了量化分析,提出了削弱关联影响的方法,并通过实际应用讨论了航道边坡测量和成图存在的问题及改进方法。