一种改进的局部加权拟合校正方法

几何校正是遥感图像处理的一个重要环节,是减弱遥感图像与地面真实形态差异的重要方法。但是常规几何校正方法对无人机影像进行校正,其效果不够理想。在分析了局部加权拟合校正法的基础上,用控制圆规定其局部校正区域,并且新增辅助控制点来覆盖该区域,以这种方法对其进行了改进。通过对同一无人机影像进行几何校正对比分析实验,结果表明:改进的局部加权拟合校正法能够更充分、合理地利用局部控制点信息,对控制点的分布具有更好的适应性,能够有效提高无人机影像的几何校正精度。     

基于深度学习算法的高分辨率无人机遥感图像自动分割

高分辨率无人机遥感图像自动分割对于图像的目标识别与检测具有重要意义,为提升图像分割精度,提出基于深度学习算法的高分辨率无人机遥感图像自动分割方法。采用直方图均衡化算法增强遥感图像后,构建基于编/解码器架构的深度学习网络语义分割模型,针对增强后的图像,在编码环节中引入残差模块强化对分割目标有效的特征;在解码环节中,采用多尺度融合模块将低层特征的局部细节信息和高层特征的语义信息相融合。同时针对遥感图像内地物类别不均衡的现象,以带权重的交叉熵为模型损失函数,克服模型选择偏好问题,提升模型分割精度。实验结果显示该方法可准确分割遥感图像内不同类型目标,分割精度达到95%以上。     

Contourlet四叉树系数方向相关性的遥感图像融合算法

近年来,遥感图像融合技术作为遥感图像处理的重要分支,在资源调查、环境监测和区域分析等领域受到广泛关注.遥感图像融合技术可以融合不同传感器获得的不同图像,获得一幅信息完整、表达准确的融合图像.Contourlet变换以其优越的非线性逼近特性和良好的多分辨率、各向异性、冗余性等特点成为处理二维及多维信号奇异性的有利工具,并广泛应用到图像融合领域.结合Contourlet变换的特征,深入分析了Contourlet系数的关联特征,提出了一种基于Contourlet四叉树系数方向相关性的遥感图像融合方法.首先对不同传感器所采集的遥感图像进行Contourlet变换,获得不同尺度下的系数分布;然后根据各尺度之间的系数满足四叉树结构关系、树中各结点的方向相关性表现出一致的特征,提出了一种新的系数相关性融合规则,能够自适应地计算融合加权系数,进而获取融合系数;最后对融合系数进行Contourlet逆变换,得到遥感融合图像.相比于传统遥感图像融合方法,新算法获得的图像信息量更加丰富,纹理更加清晰,具有较强的实用性.     

基于控制点配准算法的无人机遥感影像自动无缝拼接技术

传统无人机遥感影像自动无缝拼接技术无法精准匹配影像信息,导致无人机遥感影像拼接结果出现大量缝隙,拼接效果差。因此提出了基于控制点配准算法的无人机遥感影像自动无缝拼接技术。遵循无人机影像成像原理,获取无人机遥感影像,并将数据以图像格式文件形式存储。设置阈值,剔除最邻近域和次邻域比值大于阈值的控制点,对影像坐标平移和缩放数据标准化处理,彻底消除坐标变换对图像配准影响。构建相似变换矩阵,获取新的控制点集,使用直接线性变换算法预估变换矩阵,得到线性解。经过粗、细配准,确定不同图像重叠区域。搜索最佳拼接线,使用加权平均融合法消除拼接缝,由此设计拼接流程。由实验结果可知,该技术能够精准匹配影像信息,检测到影像最大分辨率为1000*800,具有良好拼接效果。     

面向应急响应的无人机图像快速自动拼接

根据应急响应的需求,为了快速、自动且稳定地获取遥感区域的全覆盖图像,提出一种直接适用于无人机序列图像的拼接方法.利用无人机平台上的低精度飞行控制系统与无标定的非量测相机获取序列图像,并进行快速自动配准;根据全局地面点在多视图像上的投影点集,基于单应矩阵和自由投影中心建立整体优化误差方程,并利用Levenberg-Marquardt非线性迭代求解;再根据并行几何定位拼接线的快速处理方法进行图像插值和融合,实现全流程自动化的图像输出.通过灾害应急响应的无人机遥感实验结果表明,在1h内处理完成450幅序列图像,获得定位精度小于3个像素的0.05m分辨率图像;文中方法适合无人机的序列图像配准,为应急响应提供了有效的技术支持.     

基于卷积神经网络的遥感图像分类研究

遥感图像分类是模式识别技术在遥感领域的具体应用,针对遥感图像处理中的分类问题,提出了一种基于卷积神经网络(convolutional neural networks,CNN)的遥感图像分类方法,并针对单源特征无法提供有效信息的问题,设计了一种多源多特征融合的方法,将遥感图像的光谱特征、纹理特征、空间结构特征等按空间维度以向量或矩阵的形式进行有效融合,以此训练CNN模型。实验表明,多源多特征相融合能够加快模型收敛速度,有效提高遥感图像的分类精度;与其他分类方法相比,CNN能够取得更高的分类精度,获得更优的分类效果。     

多源遥感图像融合方法研究

研究多源遥感图像的融合技术,针对不同传感器获取的遥感图像像素信息有很大差异.当所要融合的图像是多源遥感图像时,应提取多图像的有效信息,组合出高质量的图像.传统IHS图像融合方法无法避免多源图像像素不匹配带来的有效像素丢失,造成融合图像模糊,清晰度不高的问题.提出一种基于Contourlet变换的遥感图像融合方法,通过对图像进行Contourlet变换后提取各源图像的特征信息,并计算提取特征所包含的信息量,选取高信息景的特征进行融合,最后通过进行Contourlet逆变换即得到多源融合图像,利用信息量融合配准的方法就避免了直接对不匹配像素运算而造成的有效像素丢失.实验证明,改进的优化融合方法能够保留图像的有效信息,得到高清晰度的融合图像.     

基于Marr小波改进的SIFT算法的遥感影像配准

针对遥感图像配准方法中错误匹配点对过多、配准效率低和其他性能,提出了一种基于小波的遥感图像配准方法。首先,利用尺度空间理论下的Marr小波对参考图像和待配准图像进行特征提取,然后利用欧氏距离对参考图像和待配准图像的特征点进行初配准,再根据随机采样一致法,对初配准结果进行精配准。为了验证方法的有效性,选择无人机实时航拍图像、不同时相变化遥感图像以及遥感不同高度的遥感图像。实验结果表明:该方法与SIFT(Scale Invariant Feature Transform)算法以及其他改进SIFT算法相比可以有效剔除错误匹配点对,提高了配准精度,同时提高配准效率两倍以上。该方法可以应用于不同遥感数据源,能够有效地提高配准精度,降低配准时间。     

基于最佳缝合线的序列遥感图像拼接融合方法

在图像融合过程中常采用重叠区域像素加权融合方法,这会存在鬼影现象。为解决这一问题,提出了一种改进的最佳缝合线生成算法和沿最佳缝合线的融合方法,并将其应用于序列遥感图像的拼接融合。首先在重叠图像中,对重叠区域的边赋予权值,然后进行最大流最小割,最终获取最佳缝合线。在计算边权值时引入了图像梯度信息,使缝合线更准确。在图像融合时,沿最佳缝合线生成一个条带形融合区域,采用渐入渐出法对缝合线两侧的条带形融合区域图像进行过渡处理,使拼接后的图像更为真实。在序列遥感图像拼接上,采用捆绑调整算法调整拼接图像的参数来实现全局误差最小化。实验表明,该方法能够有效消除鬼影并且能获得准确的拼接图像与融合,对于序列遥感图像的拼接融合能够获得很好的效果。     

基于图像分割的无人机遥感影像目标提取技术

为全面增强遥感影像上地物波谱的反射特性能力,实现对无人机目标的无误提取,提出基于图像分割的无人机遥感影像目标提取技术;在类哈尔滤波器结构的支持下,按照区域环境中地物目标的颜色特征,完成低层影像特征的量化处理,实现基于图像分割技术的无人机遥感深度图获取;定义与无人机遥感影像相关的基本名词,通过原始特征选择的方式,判定地物波谱的平均反射特性水平,得到准确的特征元素相关性测度数值,完成无人机遥感影像的目标融合处理;在此基础上,分割多分辨率条件下的影像目标,在定义图像纹理与尺度条件的同时,得到最终的地物提取结果,实现基于图像分割无人机遥感影像目标提取技术的应用;对比实验结果表明,在初始采集相位条件及亚像素条件下,目标地物的波谱宽度均超过7.0μm,遥感影像的反射特性能力大幅提升,满足对无人机目标无误提取的实用需求。     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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