一种利用整体变分的深度恢复算法

由散焦图像恢复三维景物的深度信息是一个不适定问题.提出一种新的基于整体变分的散焦图像深度恢复算法:首先将散焦图像深度恢复转化为带有整体变分正则化项的能量泛函极值问题,然后采用变分原理将其中的最小化问题转为偏微分方程的求解,最后通过方程迭代获得深度的最优解.该算法避免了解不适定问题的逆,恢复聚焦图像等问题.模拟图像和真实图像的实验结果表明该算法是有效的,与最小二乘法相比具有较小的均方根误差.     

分数阶相位拉伸变换的图像锐化算法

图像锐化是图像增强的主要内容之一,在图像分析、图像理解以及医学图像等领域均有重要的应用。现有图像锐化方法对图像中的弱强度变化特征增强效果不明显,并且在边缘附近还会出现毛刺与噪声。为解决这些问题,提出一种基于相位拉伸变换结合相对总变分的图像锐化算法,其主要工作包括分析推导相位拉伸变换中的核函数,将传统相位拉伸变换推广至分数阶傅里叶变换,然后与相对总变分理论相结合。实验结果表明,该算法对弱强度变化特征具有更好的锐化增强效果,同时由于相对总变分的约束,也消除了增强图像边缘附近的毛刺现象。与传统锐化增强算法相比,该算法的平均梯度和信息熵提高均在80%以上,证明了该算法的有效性与优越性。     

一种新的散焦图像深度恢复算法

提出一种基于各向异性热扩散方程的散焦图像深度恢复算法。利用各向异性热扩散建模散焦成像过程,将散焦图像深度恢复转化为带有整体变分正则化项的能量泛函极值问题,通过迭代获得景物的深度信息。该算法不需要恢复聚焦图像,并且未施加额外的约束条件。模拟和真实图像实验结果表明,该算法有效,且深度恢复效果优于最小二乘法。     

小波变换和变分PDE相结合的图像去噪算法

为了更好地恢复图像,利用小波变换的思想,提出了一种变分和小波变换相结合的图像去噪算法。该算法的思想是先构造一个用带有韦伯心理学的范数估计图像正则性的变分泛函,然后在小波域中最小化变分泛函得到还原图像。与传统的直接求泛函最小化的问题有区别,该算法是用变分的思想再结合小波变换进行图像去噪。小波变换后的高频分量具有丰富的细节边缘信息,因而能够重构出高质量的图像,而且小波的引入使得新算法具有运行时间短、速度快的特点。理论分析和实验仿真表明,该算法能达到比单一方法更好的恢复效果。     

整体变分算法在图像修补中的应用研究

对如何将整体变分模型用于图像修补进行了讨论．主要研究整体变分算法在待修补区为长条形空白区域的图像修补，并根据待修补区为长条形的特点，通过引入权值，对整体变分模型的离散化算法作了改进，使该算法利用邻域信息仅对待修补空白区域进行填充，而不改变待修补区邻域的像素值．实验表明，文中算法对窄长条状或线状空白区域的图像修补是有效的。     

相位一致性原理改进的双边滤波器

为了在增强滤波器去噪强度的同时还能够保留更多的图像边缘细节信息,提出了将相位一致性原理同传统双边滤波器相结合的改进算法.根据提取图像的相位一致性信息,自适应修改双边滤波器的空间相关性和灰度相关性因子,以取得最佳的滤波效果.通过实验图像进行验证,并对处理后的图像进行了主客观还原效果评价,峰值信噪比和结构相似性指数均有较大的提升,实验结果表明了该算法的有效性和可行性.     

扩展相位拉伸变换的血管造影图像锐化

针对目前传统血管造影图像锐化增强后大量细小血管变得模糊不清或丢失,甚至增强图像中血管周围产生大量背景噪声,提出一种相位拉伸核函数,形成基于扩展相位拉伸变换的血管造影图像增强算法.该算法将"S"型群延迟相位滤波器推广到线性群延迟相位滤波器,并从理论上证明,这种线性相位拉伸的逆变换相位近似于原图的归一化二阶梯度,将高频特征传统的梯度极值表达转换为角度表达,从而更有利于凸显、增强图像中的高频特征.同时,该算法还结合相对总变分理论,将像素的邻域总变分测度与邻域内在变分测度用于增强过程,使算法更好地突出边缘轮廓与结构纹理,抑制细碎杂乱纹理与背景噪声,克服了目前方法存在的不足.利用Matlab软件平台对DeepLesion, OASIS等数据集中的部分图像数据进行实验,与传统相位拉伸变换增强算法、基于相位一致性的血管造影图像锐化算法等进行对照分析,结果表明,增强后图像上细小血管明显清晰,背景噪声得到有效的抑制,平均梯度和信息熵提高均在50%左右,证明了算法的优越性与实用性.     

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。     

激光波数扫描干涉相位解卷绕算法研究

激光波数扫描干涉技术作为一种具有微米级检测分辨率和微应变级测量精度的新型干涉图像测量方法,能够透视测量复合材料内部的微观结构信息,实现材料的高精度无损透视成像检测。作为干涉图像数据处理至关重要的环节,相位解卷绕技术能将干涉图像信息从卷绕相位展开为解卷绕相位,还原干涉图像的真实信息。在传统相位解卷绕算法中,为了避免在噪声区域展开相位时相位展开错误进而导致误差的大面积传递,往往在存在噪声的区域停止相位展开,使得解卷绕后的数据存在缺陷及视场较小的问题,甚至可能无法正常解卷绕。针对以上传统算法的问题和研究了Goldstein枝切法在相位解卷绕中的应用。通过对噪声区域进行残差点判断设置枝切线,绕过枝切线进行相位展开,在所有正常点展开后结合枝切线周边的相位信息对枝切线上相位点完成最后的解卷绕,从而实现相位更有效地展开,减少相位展开后的数据缺陷,增大展开视场,精度更高。     

一种改进的具有色彩保护的多尺度Retinex图像增强算法

针对图像增强存在的光晕伪影、颜色失真等问题,在MSRCP(Multi-Scale Retinex with Chromaticity Preservation)的基础上提出一种改进的多尺度Retinex图像增强算法。该算法首先计算原图像的强度图像;然后采用引导滤波对强度图像进行平滑处理,估计出照度分量,进而根据Retinex原理估计出反射分量;最后在颜色恢复函数中引入S型曲线函数得到最终的增强图像。实验结果表明,该算法可以有效解决光晕伪影现象,提高细节信息,使增强图像的整体色彩与原图一致,改善了图像整体的视觉效果。     

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