重庆市城市道路信号交叉口机动车交通特性研究

在城市道路网中,平面交叉口是城市道路通行能力和交通安全的瓶颈。由于社会经济、文化背景、道路环境等的不同,不同地区的交通活动表现出不同的行为特征。本文采用视频技术和人工观测技术,研究了重庆市机动车在市政道路信号平面交叉口时的交通特征,为交叉口立体空间设计和信号配时优化提供了基础数据。     

重庆市城市道路信号交叉口机动车交通特性研究

在城市道路网中,平面交叉口是城市道路通行能力和交通安全的瓶颈。由于社会经济、文化背景、道路环境等的不同,不同地区的交通活动表现出不同的行为特征。本文采用视频技术和人工观测技术,研究了重庆市机动车在市政道路信号平面交叉口时的交通特征,为交叉口立体空间设计和信号配时优化提供了基础数据。     

被动公交优先的交叉口信号周期优化模型研究

在城市道路交叉口实行公交优先控制可以提高公交效率及准点率,降低运营成本,吸引乘客,可缓解我国城市交通问题。介绍了基于乘客人均延误最小为目标,在单点交叉口被动公交优先控制理论的基础上,建立了被动公交优先的周期优化模型,结合现场实例,将现有交通控制条件下的效益分析结果与按公交优先的最佳周期时长的确定及效益分析进行比较,说明周期优化的可行性。     

Pavement Distress Analysis Using Image Processing Techniques

Abstract: We demonstrate the feasibility of applying image processing techniques to the analysis of pavement distress due to cracking. Pavement image samples were obtained using a custom-designed data acquisition system called the Automatic Crack Monitor (ACM). The image samples conteining pavement cracks are parameters, are extracted using techniquesw described in this paper. The crack parameters are necessary measures used in calculations of the Pavement Serviceability Index (PSI), which is used by highway maintenance engineers to decide whether a certain pavement section needs to be repaired. Experimental results are shown and the potential harware implementation of the developed techniques is also discussed.     

Enhanced Roadway Inventory Using a 2-D Sign Video Image Recognition Algorithm

Abstract:   This article presents a two-dimensional (2-D) color, shape, and texture-based stop sign recognition algorithm. The theoretical base of establishing a suitable 2-D correlation coefficient threshold value that can both eliminate nonstop sign objects and minimize the possibility of false-positive identifications is presented. Both the one-dimensional (1-D) algorithm, which has been developed by the authors, and the 2-D algorithm provide a simple and feasible means to automatically extract stop signs from roadway inventory video images with a very competitive computation speed of less than 25 ms for processing a 400 × 300 pixel image. The 2-D algorithm was able to correctly detect all of the images that were correctly detected by the 1-D algorithm. In addition, the 2-D algorithm could correctly detect two of the remaining five images that could not be correctly detected by the 1-D algorithm. The type of images that can be correctly detected by the 2-D algorithm but not the 1-D algorithm is significant because there is a need to recognize the tilted stop signs. The 2-D algorithm can detect stop signs tilted up to 35°. Similarly, the 2-D algorithm can detect a stop sign with its surface being blocked up to 20%. The improved detectability, with only a marginally increased time in the image processing, suggests that the 2-D algorithm is a better algorithm than the 1-D algorithm for processing stop sign images from video logging of roadway inventory. This algorithm can be extended to recognize other signs, such as yield signs, with a slight modification.     

使用图像分析研究隧道衬砌管片的位移变化

以复合材料加固前后的盾构隧道管片为对象,进行了盾构隧道管片在侧向荷载作用下变形能力和极限承载力的整环加载试验,使用图像处理技术对加固前后衬砌圆环管片接缝两侧的位移变化进行了研究。根据加载过程中不同时刻的试验图像,使用粒子图像测速技术得到了不同时刻、不同位置接缝两侧混凝土管片的位移变化情况。结果表明:未加固阶段管片顶部接缝处管片表面位移相对较小,两侧位移变化不相等,封顶块位移大于邻接块位移,加载结束时最大位移发生在封顶块位置;整环加固后,封顶块位移大于邻接块位移,加载结束时裂缝开始扩展;加固前后位移变化幅度大小次序依次是封顶块、标准块、邻接块和底块,破坏最先发生位置是封顶块和邻接块的连接位置;使用复合材料加固后,各处接缝两侧管片位移变化幅度及整体位移变化量均小于加固前,管片承载力增加,强度明显提高。本文结果对研究隧道衬砌破坏机理有一定的参考价值。     

Rapid Early Fire Smoke Detection System Using Slope Fitting in Video Image Histogram

Fire Technology - Fire is one of the most dangerous natural/manmade disasters that endangers human life and property. Although early fire smoke detection systems have become increasingly...     

超高层建筑工程变形监测中小角度钢尺测边交会点的精度改良

通过规范中的测边交会点的坐标计算公式,按误差传播规律,分析出交会点的误差计算公式.在此基础上,通过理论分析,改良小角度三角形图形强度,找出测边交会小角度三角形的最高精度的交会点,分析坐标值及其点位最高精度值.研究结果表明,改良后交会点位精度值除与最佳图形--等边三角形的交会精度很接近外,还提高了变形监测点的精度等级.同时为变形监测、控制测量、施工放样测量等工作中出现小角度三角形,为优化测量点位误差提供了一种解决问题的新途径.     

联合MW和TECR法进行GPS/GLONASS双频非差数据周跳的探测与修复

针对Turbo Edit方法在周跳探测与修复方面的不足,采用联合MW和TECR组合观测值进行周跳处理的方法。通过对GPS/GLONASS静态测量数据的计算分析结果证明该组合法可探测出Turbo Edit方法不能探测出的周跳,对于GPS/GLONASS双频非差数据周跳的探测与修复,该算法有效可行,有很强的实用性。     

Remote Video Sensing of Highway Pavements at Road Speeds: Using the Motorola 68020 Microprocessor

This article presents microprocessor measurement techniques for a multi-cameera video system mounted in a van type vehicle that will observe a 12-foot lane of road surface. Because of the high speed processing requirement of the vision system, several 68020 microprocessors are employed to handle data and detect various cracking patterns while the vehicle is in motion at highway speeds. As the image processing system collects the data, a host microprocessor computes an instantaneous and cumulative pavement score that will be used by the operator and the Pavement Management System, PMS, for further analysis and maintence considerations. The article presents an overview of the microprocessor driven PMS using high speed hardware circuitry for real-time processing. Development of the system is underway by the Earth Technology Corporation and Louisiana Tech University.     

A texture‐Based Video Processing Methodology Using Bayesian Data Fusion for Autonomous Crack Detection on Metallic Surfaces

Regular inspection of the components of nuclear power plants is important to improve their resilience. However, current inspection practices are time consuming, tedious, and subjective: they involve an operator manually locating cracks in metallic surfaces in the plant by watching videos. At the same time, prevalent automatic crack detection algorithms may not detect cracks in metallic surfaces because these are typically very small and have low contrast. Moreover, the existences of scratches, welds, and grind marks lead to a large number of false positives when state‐of‐the‐art vision‐based crack detection algorithms are used. In this study, a novel crack detection approach is proposed based on local binary patterns (LBP), support vector machine (SVM), and Bayesian decision theory. The proposed method aggregates the information obtained from different video frames to enhance the robustness and reliability of detection. The performance of the proposed approach is assessed by using several inspection videos. The results indicate that it is accurate and robust in cases where state‐of‐the‐art crack detection approaches fail. The experiments show that Bayesian data fusion improves the hit rate by 20% and the hit rate achieves 85% with only one false positive per frame.     

拉萨市北郊水厂太阳能供暖工程实例

本文是关于一个拉萨市太阳能供暖试点工程的成功实例。文中提出了该工程的设计方案和原理,并对供暖系统采集的数据进行了分析计算,这些数据对拉萨市现状建筑的采暖设计参数的选取以及太阳能供热系统的优化设计都具有重要意义。