一种基于视频序列单目视觉下的运动车辆轮廓重构算法

针对运动车辆在单目视觉下轮廓重构的问题,本文通过特征目标识别的方法解算出无约束运动车辆的运动参数,将无约束运动物体的轮廓重构问题转化成已知约束运动物体的轮廓重构问题,提出了一种基于视频序列的单目视觉下的运动车辆轮廓重构算法.实验结果证明,新算法能够较好地重构出不同大小车辆的3D轮廓,其车辆高度估算值的误差在4%以内     

基于元胞自动机模型的道路突发瓶颈现象研究

针对特殊交通事件诱发的道路突发瓶颈现象,结合驾驶员在瓶颈现象发生前后的行为变化,提出了一个考虑驾驶员在瓶颈处驾驶特性的元胞自动机模型,并利用该模型分析了瓶颈现象对驾驶特性的影响.结果发现,该模型可以刻画不对称换道和瓶颈处抢道行为所产生的一些复杂的交通现象.研究表明,在瓶颈处实行不对称交替通行可以提高系统流量.     

Long-range correlation analysis of urban traffic data

<正>This paper investigates urban traffic data by analysing the long-range correlation with detrended fluctuation analysis.Through a large number of real data collected by the travel time detection system in Beijing,the variation of flow in different time periods and intersections is studied.According to the long-range correlation in different time scales, it mainly discusses the effect of intersection location in road net,people activity customs and special traffic controls on urban traffic flow.As demonstrated by the obtained results,the urban traffic flow represents three-phase characters similar to highway traffic.Moreover,compared by the two groups of data obtained before and after the special traffic restrictions(vehicles with special numbered plates only run in a special workday) enforcement,it indicates that the rules not only reduce the flow but also avoid irregular fluctuation.     

The effect of stochastic accelerating and delay probability with the velocity and the gap between vehicles on traffic flow

This paper proposes a new combined cellular automaton (CA) model considering the driver behavior of stochastic acceleration and delay with the velocity of the preceding vehicle and the gap between the successive vehicles based on the WWH model and the noise-first NaSch model. It introduces the delay probability varying with the gap, adds the anticipation headway and increases the acceleration with a certain probability. Through these simulations, not only can the metastable state and start--stop wave be obtained but also the synchronized flow which the wide moving jam results in. Moreover, the effect of stochastic acceleration and delay on traffic flow is discussed by analyzing the correlation of traffic data. This indicates that synchronized flow easily emerges in the critical area between free flow and synchronized flow when acceleration and delay are synchronized or their probability is close to 0.5.     

一种对实摄图象的变形矫正算法

提出了一种对实摄图像的变形矫正算法。它通过对目标区域在水平和垂直方向计算差分，并对投影所得结果计算方差，找出使方差达到最大的直线，并按这两条直线来对原图进行矫正。结果显示，用此方法不仅对于矫正实摄车辆牌照字符的变形有较好的效果，而且对其他字符以及一些图形图象也有一定的矫正效果。