SMA沥青混凝土路面材料荷载行为模式研究

采用图像处理分析技术观察SMA沥青混凝土及密级配沥青混凝土在荷载作用下其粗集料移动轨迹的变化,定量描述SMA沥青混凝土粗集料构架形成机制、抗车辙能力成因、粗集料材料形状组合因子偏差等因素,建立粗集料移动轨迹与车辙量的行为模式,研究SMA沥青混凝土材料荷载行为,以使其应用于公路及机场路面能完全发挥其特性。研究结果表明:SMA沥青混凝土粗集料碾压过程中粗集料趋向水平方向移动,且移动量小,粗集料构架处于最稳定阶段,故SMA沥青混凝土车辙量较小,抗车辙能力较好;密级配沥青混凝土中粗集料趋向垂直方向移动,粗集料移动量大,容易造成粗集料构架不稳定,故沥青混凝土车辙量较大。     

An innovative method for the analysis of vehicle movements in roundabouts based on image processing

The objective of this paper is to propose a method, based on the image processing of field survey data, to analyze vehicles movements into roundabouts. This research study consisted of three stages: a field survey to collect vehicular flow images captured by video cameras, the processing of these images using a proprietary software (VeTRA—Vehicle Tracking for Roundabout Analysis), and finally, the analysis of the collected data. The main feature of the software is that it allows the automatic computation of the main variables necessary to rank and evaluate a generic roundabout: the entry/exit (E/E) matrix with classification of vehicles (e.g., heavy, light, and motorbikes), vehicle trajectories, and vehicular speed diagrams along the paths inside the roundabout. The processing system is robust enough to withstand classic problems affecting image processing such as variable wind conditions, cloud cover, shadows, and obstructions. Calibration and error evaluation have been deduced from data collected by a high precision Real Time Kinematic GPS video recording system mounted on a probe vehicle. Data of E/E matrices generated by VeTRA are compared with those manually counted on the corresponding video images. A case study of an existing roundabout is featured in the paper. The results indicate that the software has a high capability of generating the E/E matrix. The analysis of vehicular trajectories with both the plot of curvature diagrams and the corresponding speed diagrams enable the evaluation of driver behavior relative to the geometric shape of the roundabout. Copyright © 2011 John Wiley & Sons, Ltd.     

Differences in air passengers’ buying behaviour: findings from Korean and Australian international passengers

Abstract

This paper investigates how air passengers’ expectations, ticket price, airline service quality, value, passenger satisfaction and airline image determine their buying behaviour. To test the conceptual frameworks, path analysis was applied to data collected from Korean and Australian international passengers to examine differences between these two groups. Further analyses were undertaken on different passenger segments between national and foreign airline passengers. The results of the path analysis reveal that air passengers’ buying behaviour differs significantly between Korean and Australian international passengers. Results also reveal that the determinants of air passengers’ buying behaviour differ by airlines.     

基于遥感图像信息特征的单调递增SSDA算法

图像配准就是将不同时间、不同传感器或不同条件下对同一景物获取的两幅或多幅图像,进行比较找到该组图像中的共有景物,或是根据已知模式到另一幅图中寻找相应的模式。利用遥感图像进行目标监测需要进行图像配准处理。匹配算法如何达到高精度、高匹配正确率和实时性成为人们追求的目标。文章在传统匹配算法的基础上,提出两点改进:一是通过PCA-圆形SIFT算法提取图像特征角点,降低维数,优化计算;二是利用图像角点作为单调递增阈值序列SSDA算法匹配的基本像素点,利用遥感图像信息特征降低匹配计算量。最后进行实验仿真,结果表明,改进后的算法使得配准速度进一步提高,能够满足遥感图像配准实时性的要求。     

Image analysis of aggregate, mastic and air void phases for asphalt mixture

The shape characterization and spatial distribution of aggregate,mastic and air void phases for asphalt mixture were analyzed.Three air void percentage asphalt mixtures,4%,7% and 8%,respectively,were cut into cross sections and polished.X-ray scanning microscope was used to capture aggregate,mastic,air void phase by the image.The average of polygon diameter was chosen as a threshold to determine which aggregates would be retained on a given sieve.The aggregate morphological image from scanned image was utilized by digital image processing method to calculate the gradation of aggregate and simulate the real gradation.Analysis result shows that the air void of asphalt mixture has influence on the correlation between calculation gradation and actual gradation.When comparing 4.75 mm sieve size of 4%,7% and 8% air void asphalt mixtures,7% air void asphalt mixture has 55% higher than actual size gradation,8% air void asphalt mixture has 8% higher than actual size gradation,and 4% air void asphalt mixture has 3.71% lower than actual size gradation.4% air void asphalt mixture has the best correlation between calculation gradation and actual gradation comparing to other specimens.The air void percentage of asphalt mixture has no obvious influence on the air void orientation,and three asphalt mixtures show the similar air orientation along the same direction.     

基于图像融合和DCT域增强的人脸识别

提出了一种基于图像融合和DCT域增强的人脸识别方法.首先对人脸图像分别进行直方图均衡化和对指数变换,将二者变换结果融合,减少光照对人脸识别的影响;然后进行DCI变换,在滤除高频分量的同时进行图像增强,抑制块效应,在此基础上进行IDCT图像重建,利用二维主成分分析提取人脸特征,降低空间维数;最后通过最邻近分类法实现人脸识别.Yale人脸库仿真实验表明,该方法在光照变化较大和人脸样本较少的情况下具有较高的识别率.     

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。     

一种基于稀疏表示的交通图像去噪算法

将图像稀疏表示方法引入到交通图像处理中,实现了一种基于K-SVD的正交匹配追踪的交通图像去噪算法.该算法通过奇异值分解,DCT字典进行自适应更新,形成更能表示图像结构的超完备字典.实验结果表明,相对于传统图像增强方法(中值滤波、均值滤波、基于小波滤波)和基于DCT冗余字典的稀疏表示图像增强方法,该算法能更有效地去除交通图像噪声,得到更高的峰值信噪比.     

基于邻域相关的自适应中值滤波算法

为改善图像效果,在对现有的椒盐噪声自适应中值滤波算法分析的基础上,提出了基于邻域相关的自适应中值偏移滤波算法。算法对自适应中值滤波算法的处理过程进行改进。当滤波窗口大于设定的最大值时,根据像素点邻域内的像素点灰度值分布在不同的区间,将像素点灰度值的复原分为偏大或偏小两种情况。受污染像素点的滤波输出值为偏移的中值,偏移的距离根据改进的自适应中值滤波算法运行时滤波窗口的大小来决定。从仿真结果可见:该算法滤波后的图像具有较高的峰值信噪比,对图像细节的保留能力和抑制椒盐噪声的能力都有一定的提高。     

基于 Web语义的舰船雷达目标识别系统设计

针对舰船雷达信号目标的识别方式简单、识别度低的情况,文中提出基于 Web语义的舰船雷达回波自动识别系统。因为雷达信号目标特征信息点分散且繁杂,在语义 Web网下取得雷达信号目标图像的数据特征,运用改进 FastICA算法提取特征数据后,通过智能雷达回波视频图像识别系统,对舰船目标图像进行分析。实验证明,基于 Web语义的舰船雷达目标识别系统,能使大量信息被系统充分利用,达到精确识别舰船雷达图像目标的目的。