基于遥感数据光谱和空间特征的边缘提取方法

传统的边缘检测算子(Sobel、Robert、Prewitt、Kirsch、Gauss—Laplac等算子)主要是通过图像空域特征微分，建立不同结构的模板完成高分辨率遥感图像的边缘提取。而高分辨率遥感数字图像包括了空间域和光谱域两种信息，借助这两种特征信息提高提取城市边缘的信息精度已经成为当前算法开发的基本思路。本研究采用了“象元替换”的思想设计光谱分解和边缘检测的算子模板步骤，综合了图像的光谱特征和空间特征信息。研究结果表明，这种方法有效地提高了城市遥感数据边缘信息的提取精度，同时还具有方法简便、计算速度快的特点。     

结合无下采样Shearlet变换和改进尺度积的边缘提取

为了解决遥感图像边缘提取中的伪边缘现象,提出了一种基于无下采样Shearlet变换模极大值和改进数学形态学的边缘提取算法。首先,通过无下采样Shearlet变换对目标遥感图像提取高频分量和低频分量;针对小尺度边缘系数受噪声影响过大,对相邻2个尺度较大的高频系数进行改进,得到尺度多方向的高频系数。然后,采用非模极大值抑制方法对高频系数进行处理,提取高频分量的目标边缘;采用改进的数学形态学方法对低频分量进行处理提取低频目标边缘。最后,将高低频边缘提取结果加权融合,并使用区域连通法去除孤立噪声点,得到最终边缘提取结果。实验表明,与Canny算法、基于NSCT模极大值+Canny算法、基于NSCT模极大值+数字形态学3种算法相比,该算法提取的目标边缘轮廓不仅完整清晰,连续性好,还具有较强的抗噪性。     

基于遥感数据特征和像元替换技术的边缘提取方法

随着城市化的发展，城市遥感领域在中国发展迅速。高分辨遥感图像的边缘提取是当前城市遥感的重要研究领域。实践中，传统的边缘检测算子主要是通过图像空城特征微分，建立不同结构的模板完成。高分辨率遥感数字图像包括了空间域和光谱域两种信息，因此，借助于图像的光谱和空间域两种特征信息提高提取城市边缘信息精度已经成为当前算法开发的基本思路。该研究通过设计光谱分解和边缘检测的算子模板，综合利用了图像的光谱、空间特征信息。研究结果表明，这种方法有效地提高了城市遥感数据边缘信息的提取精度，同时还具有方法简便、计算速度怏的特点。     

基于NSST和改进数学形态学的遥感图像目标边缘提取

为了从遥感图像中提取出更为准确完整的目标边缘,提出一种基于无下采样Shearlet模极大值和改进数学形态学的目标边缘提取方法。首先采用无下采样Shearlet变换(NSST)将图像分解成边缘细节丰富的高频分量和边缘细节较少的低频分量;然后结合不同分解程度下边缘像素点处的系数关系,对高频分量的各个子带进行模极大值检测,再经过双层掩膜筛选后得到高频边缘提取结果;对低频分量采用改进的数学形态学方法,得到低频边缘提取结果;最后将上述两部分融合,使用区域连通方法去除孤立点,得到最终的目标边缘图像。大量实验结果表明,与Canny以及其他4种同类边缘提取方法相比,本文方法所得边缘定位准确、完整清晰、细节丰富,且抗噪能力强,为后续遥感图像目标特征提取与识别奠定更好基础。     

基于PCA和数据融合的遥感图像数字水印算法

提出了一种向遥感图像中嵌入水印以保护其版权的算法。算法将数据融合技术和数字水印技术相结合,首先将全色图像进行小波分解,提取图像分解后的第三级低频边缘特征,利用PCA变换得到边缘特征的第一主分量作为水印信息,将水印与第三级中频进行融合;然后进行小波逆变换得到重构图像;最后采用小波变换和PCA融合法将含有水印的全色图像和多光谱图像相融合。提取水印时使用独立分量分析(ICA)方法。实验表明,该算法可以保护遥感图像的版权和进行真伪认证,且不破坏原始遥感图像的信息和特征,是有效可行的。     

融合小波变换和形态学差分的图像边缘检测

图像边缘检测的关键是在尽量多检测到边缘的同时更有效地抑制噪声,为此提出了一种融合小波变换和形态学差分算法的边缘检测方法。将源图像进行小波分解,高频分量利用小波模极大值算法进行边缘检测,可有效提取高频边缘;低频分量采用形态学差分算法进行边缘检测,能够检测出低频边缘;采用一定的融合规则将两个边缘检测图像融合在一起。实验结果表明,该方法优于单独使用小波模极大值法或数学形态学法,对噪声具有很好的鲁棒性,得到的图像边缘连续、清晰。     

基于形态学和小波的遥感图像边缘检测

针对遥感图像噪声含量大、边缘细节丰富等特点,提出了一种基于形态学和小波分析相结合的遥感图像边缘检测方法,即利用小波变换将遥感图像分解为低频和高频两部分分别进行处理,低频采用形态学锐化算法改善低频边缘清晰度后构造全方位多结构元素进行形态学边缘检测,高频引入小波阈值去噪算法进行预处理后利用小波模极大值进行边缘检测,最后进行边缘图像融合.实验结果表明:该方法在有效抑制噪声的同时,实现了边缘的精确定位,细节提取效果好.     

结合相位一致与全变差模型的高分辨率遥感图像边缘检测

目的边缘检测是有效利用遥感数据开展地物目标自动识别的重要步骤。高分辨率遥感图像地物类型复杂,细节信息过于丰富,使得基于相位一致的边缘检测结果中存在过多的噪声与伪边缘。为此提出了一种结合相位一致与全变差模型的高分辨率遥感图像边缘检测方法。方法根据相位一致原理,应用Log Gabor构造的2维相位一致模型,引入全变差去噪模型对基于相位一致的边缘强度图进行改进。结果借助有界变差空间对图像光滑性的约束,实现了高分辨率遥感图像噪声去除与伪边缘抑制,利用改进后的相位一致边缘强度图可有效检测高分辨率遥感图像的边缘。结论实验结果表明,与相位一致模型、Canny算法相比,该方法能消除了高分辨率遥感图像中同类地物内部细节特征形成的噪声,抑制相位一致边缘检测结果中的伪边缘,突出地物的真实边缘,并能正确地提取地物目标的整体轮廓信息,有助于后续地物目标的自动识别。     

基于区域小波统计特征的遥感图像融合方法

提出一种基于区域小波统计特征的遥感图像融合方法,对多光谱图像的I分量与直方图匹配后的高分辨率图像进行小波变换融 合。对分解后的低频分量采用加权平均的融合规则,高频分量则根据其区域的小波系数特征,采用基于区域方差匹配度的融合规则。对 SPOT多光谱图像和高分辨率图像进行融合实验,并利用信息熵和相关系数对融合结果进行客观评价与比较分析。仿真实验结果表明,基于区域小波统计特征的融合方法能达到较好的融合效果。     

基于边缘特征和能量的图像融合方法

根据低频域平均法,提出基于低频边缘特征和能量的多聚焦小波图像融合方法,对需要融合的图像进行小波多尺度分解,按区域能量最大化原则对高频细节分量图像进行融合,对低频近似分量图像采用能量与边缘特征相结合的融合方法。实验结果表明,与原有方法相比,该方法能更好地体现低频域边缘特征和区域特征。     

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.     

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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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