基于改进光流特征的运动目标跟踪

在城市智能视频监控中需要对运动目标进行实时跟踪,针对传统的运动目标检测中出现的跟踪目标易丢失、跟踪率低、实时性差等问题,提出一种基于改进光流特征的运动目标跟踪检测方法,对运动行人目标进行跟踪。该方法首先采用改进的Vibe运动背景建模法对视频中存在的运动行人进行检测,再将Shi-Tomasi角点检测与LK光流法进行结合,将角点检测结果融入到LK光流法中,并对检测到的角点进行运动光流特征提取,最后通过卡尔曼滤波对出现的行人进行预测跟踪,采用匈牙利最优匹配算法实现对运动目标的持续匹配以及对运动目标的跟踪。仿真结果表明,本文提出的方法能够对视频中出现的运动目标进行检测跟踪,具有较好的识别效果,且检测效率得到提高。      

基于时空结构张量的高速公路视频车辆检测

详细分析高速公路车辆运动模式与视频监控序列图像的特征,本文针对目标运动速度较大时,背景差分法运算复杂和连续帧差法容易产生虚影的情况,提出基于时空结构张量的光流分析法进行高速公路视频车辆检测。实验结果表明,该算法简洁并且能对高速公路视频序列中的运动车辆进行较准确的分割,为下一步的运动跟踪提供了可靠的依据。     

煤矿井下视频多目标轨迹跟踪算法研究

为了提高煤矿井下监控视频的目标识别准确率,对运动目标进行有效跟踪,将小波变换和背景差分法相结合,对Camshift算法进行改进,提出了适用于煤矿井下视频多目标轨迹跟踪算法。首先采用小波三层变换对视频图像进行去噪处理,得到低频图像。然后再进行背景差分运算,检测出运动目标。最后采用Camshift算法对运动目标进行跟踪处理。实验结果表明,改进的Camshift算法减少了原始Camshift算法在初始候选目标时的随机性,提高了目标检测和跟踪的准确率,为煤矿的安全生产提供了保证。     

基于对极几何约束的动态背景下运动目标检测

针对动态背景下运动目标的检测问题,提出了一种基于对极几何约束的检测方法。该方法利用了视频序列中相继帧对应的背景角点满足对极几何约束条件这一原理,先提取前一帧的Harris角点,然后利用金字塔分层的Lucas-Kanade光流法获得在下一帧的对应点;利用随机采样一致性算法估计出基础矩阵,来识别背景角点和前景角点;对得到的前景角点进行聚类,每一类对应于一个运动目标区域。实验结果表明,该方法检测准确度高、检测速度快,满足实时处理的需求。     

一种改进的帧间差光流场算法

结合运动目标检测帧差法运算速度快和光流法活动目标检测准确度高的特点,提出一种改进的帧间差光流场计算的运动目标检测算法。在帧差部分采用隔帧差分从而可以检测到帧间位移小于1个像元而多帧累积位移大于1个像元的运动点目标;在光流计算时,引入通用动态图像模型（GDIM）建立新的光流约束条件,克服了亮度变化引起的约束方程不成立问题。算法仅对帧差法后图像中不为零的像素进行光流场计算,提高了目标检测的准确性和检测速度。仿真实验证明了该算法的有效性。     

慢运动背景下运动目标提取算法*

提出一种慢运动背景视频序列下基于帧间背景图像匹配的运动目标检测和提取算法。该算法首先使用仿射变换模型来描述慢运动背景图像的运动变化,并使用基于光流约束方法求解该仿射变换模型参数,实现了相邻帧间图像的背景匹配;其次,采用背景匹配后的两帧图像差进行目标检测,使用自适应二值化区分变化与未变化区域;最后,使用形态学等图像算法进行后处理提取运动目标。算法经实验证明,在背景慢运动情况下可以有效地提取出运动目标。     

室内视频监控中行人目标检测与跟踪方法

为了有效检测和跟踪室内环境下视频监控中的行人目标,本文提出了一种新的行人检测与跟踪算法。检测阶段采用隔帧差分图像法以及自适应闽值分割技术快速检测运动行人;跟踪阶段采用卡尔曼滤波对目标位置进行预测,并利用最小外接矩形框优化匹配搜索。实现运动行人连续跟踪。通过单人、多人交互两组视频序列对算法进行了验证,试验结果表明。本文算法能够较好地处理室内静止背景下单人、多人跟踪,并对目标遮挡有一定的鲁棒性。     

基于时空信息的多运动目标跟踪算法

利用帧差法和基于Sampson距离的随机抽样一致性（RANSAC）匹配算法,实现基于时空信息的多运动目标跟踪。采用帧差法获知运动目标大概位置,运用Harris算法提取每帧视频图像中运动目标的角点,并对其进行归一化处理,利用RANSAC算法对角点进行匹配,使用闽值分割法确定运动目标位置。实验结果表明,该方法能准确跟踪相似目标,其实时性较高。     

视频目标运动分析研究

首先分析了OpenCV中BlobTrack运动模块的跟踪算法流程,接着对帧间差分、背景差分、多帧累加和光流法等常见的运动目标检测方法进行了比较,并提出了采用差异累计图像法对运动目标进行检测,然后重点分析了MeanShift算法原理,最后指出了采用BlobTrack跟踪时各个参数选取的问题,并通过Matlab仿真证明了BlobTrack在智能视频监控系统中的适用性。     

基于TBD的粒子滤波红外点状动目标跟踪算法研究

提出了一种新的低信噪比红外序列图像运动点目标检测与跟踪算法,该算法有机地结合了TBD检测算法与粒子滤波跟踪算法。首先通过多帧TBD处理后,检测出运动目标的初始位置和运动速度,然后在跟踪阶段采用粒子滤波算法估计目标运动状态,可实现信噪比为2的点目标的检测与跟踪。对真实红外图像序列进行实验仿真,仿真结果证明,该算法具有良好的实时性与很高的精确性。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.