亮度分区自适应对数色调映射算法*

色调映射可将高动态范围图像显示在低动态范围显示器上。常用的对数全局色调映射算法由于压缩范围有限容易引起细节丢失,为此本文给出一种基于亮度分区的自适应对数色调映射算法。首先将高动态范围图像由RGB颜色空间转换为XYZ颜色空间以提取图像亮度信息,然后将亮度图分为高、中、低三个照度区域。根据区域亮度属性实施对数色调映射实现动态范围局部压缩,并进行融合处理以消除区域交界处的显示效果。同时采用双边滤波技术进行细节补偿。实验结果表明,此算法能有效压缩动态范围并再现真实场景信息,同时可以保留丰富的细节。     

改进拉普拉斯金字塔模型的高动态图像色调映射方法

高动态图像的色调映射是图像处理的研究热点,用于解决常规色调范围显示设备无法有效显示高动态图像的问题.针对当前色调映射不能精准地显示出图像内容(如丢失细节、模糊弱边缘)的问题,提出一种改进拉普拉斯金字塔模型的高动态图像色调映射方法.首先基于滤波和下采样处理计算出对输入图像进行了简单去噪的高斯金字塔;然后通过约束强边缘数量分离出高斯金字塔中每层图像的强?弱边缘和细节;再针对每层图像构造其分层映射函数,通过增强细节、弱边缘的对比度以及保持强边缘对每层图像进行逐点映射,并据此计算描述每层对比度变化的拉普拉斯金字塔;最后根据拉普拉斯金字塔自底向上重构出目标图像.与已有的多种色调映射方法相比,根据客观评价和主观评价的结果表明,文中方法能增强细节和弱边缘、避免强边缘处梯度反转,更清晰、准确地显示出高动态图像内容.     

一种改进的多尺度Retinex色调映射算法

传统的低动态范围显示设备不能很好地表现高动态范围图像信息,针对这一问题,提出一种基于引导滤波的Retinex多尺度分解色调映射算法。该算法使用引导滤波对光照信息进行估计,将高动态范围图像的亮度分为光照层和反射层;然后对反射层分量进行多尺度分解,得到一系列细节层和一个基本层,将细节层和基本层进行合并和色彩还原;最后得到色调映射后的图像。实验结果表明,该算法可以较好地还原真实场景信息,映射后图像的细节和对比度较好,色彩鲜艳。     

一种分组实现的高动态范围图像显示方法

针对低动态显示设备严重制约高动态范围图像显示的缺点,提出了一种基于分组的高动态范围图像色调映射技术,利用双边滤波技术对图像亮度值进行初步校正,对所得数据进行分组,根据分组数据的平均值惟一确定一个伽马值对图像亮度进行最终修正。实验结果表明,该方法不仅能够实现动态范围压缩,而且能够有效避免光晕和色差等现象,可以广泛应用于各种低动态设备中。     

高动态范围图像(HDRI)编码及色调映射技术研究

在分析和讨论了高动态范围图像的基本理论和获得技术的基础上,深入剖析和研究了高动态范围图像编码的几种技术方法和途径,并分析了各自的特点和应用。同时还讨论了高动态范围领域中的色调映射技术,特别针对高动态范围图像色调映射中的背景强度的计算方法进行了研究,最后还对高动态范围图像技术的应用领域和前景进行了展望和预测。     

宏微观信息增强与色彩校正的高效色调映射

目的 色调映射是一种在保持视觉效果基本不变的前提下将高动态范围图像映射到常规低动态显示设备上进行显示的技术。针对现有方法存在细节模糊、边缘光晕及色彩失真等不足,提出一种宏微观信息增强与色彩校正的色调映射新方法。方法 将给定的高动态范围图像映射到HSV(hue, saturation, value)颜色空间,分离亮度信息与色彩信息。基于人类视觉感知机制,在亮度通道构建宏观一致性和微观显著性的亮度感知压缩模型,并进一步通过调节模型缩放因子消除边缘光晕现象。基于颜色恒常性原理,在色度通道构建自适应饱和度偏移模型,融合亮度压缩信息调整图像的饱和度信息,解决色调映射所造成的主观色彩失真问题。结果 实验结果表明,所提算法在结构保真度、自然度和色调映射质量指数等客观评价方面均优于对比色调映射算法,同时主观平均意见值也取得了最高的4.3分（即好—非常好）。结论 宏微观信息增强的亮度感知压缩模型,在确保场景亮度信息不变的情况下,可以有效增强图像纹理细节的完整性和保真性。融合亮度压缩的饱和度偏移模型可以有效解决亮度压缩导致的图像色彩失真等问题。该色调映射算法效率高、通用性强,可广泛应用于图像压缩、生物医学...     

基于相机响应曲线的高动态范围图像融合

高动态范围成像技术由于能够更加真实地再现成像目标及周围场景,在军事、航天等领域具有重要的研究价值。首先利用佳能1DC针对同一场景拍摄不同曝光量的序列图像,通过推导计算获得彩色图像各通道的相机响应曲线;然后通过建立图像灰度值与辐照度之间的照度映射获得一幅高动态范围的辐照度图像;其次利用基于双边滤波色调映射算法对获得的高动态范围图像进行压缩;最后通过基于镜面反射白平衡算法对图像进行色彩校正,从而获得拍摄场景的高动态范围图像。抽取不同帧数的实验拍摄图像对所提算法进行有效性验证,通过实验结果分析该算法实现高动态范围图像融合所需最少图像帧数为4帧。     

多级半色调技术在电纸书显示优化中的应用

针对电纸书显示屏灰度等级不足的问题,提出了利用半色调图像处理技术的改进算法实现电纸书显示优化的方法.在阐述半色调技术与电子纸特点的基础上,介绍了抖动算法和误差扩散算法,通过对这两种算法进行改进提高电纸书显示的灰度级数及视觉效果.其中重点对误差扩散算法中的阈值、滤波器及扫描方式的设定进行设计,并提出一种基于误差动态检测的新的改进算法,能有效提高图像灰度级数,改善电纸书的图像显示质量.最后在电纸书系统平台上实现仿真,通过质量评价参数客观地评测了各种算法.     

基于多尺度分解的色调映射算法

针对高动态范围(HDR)图像显示于普通显示设备的问题,提出一种新的基于多尺度分解的色调映射(TM)算法。首先利用局部边缘保留(LEP)滤波器对HDR图像进行多尺度分解,有效平滑了图像的细节同时保留了突出的边缘;根据分解后各层的特点和压缩的要求,提出一个带参数的动态范围压缩函数,通过变化参数以便压缩图像的粗尺度层并增强细尺度层,从而压缩图像的动态范围并增强细节;最后重组各层并恢复颜色,所得到的映射后图像具有良好的视觉效果。实验结果证明,该方法在自然度、结构保真度和整体的质量评价上都要优于Gu等(GU B,LI W J,ZHU M Y,et al.Local edge-preserving multiscale decomposition for high dynamic range image tone mapping[J].IEEE Transactions on Image Processing,2013,22(1):70-79)和Yeganeh等(YEGANEH H,WANG Z.Objective quality assessment of tone-mapped images[J].IEEE Transactions on Image Processing,2013,22(2):657-667)提出的方法,同时也避免了局部色调映射算法所普遍存在的光晕效应。该算法可以用于HDR图像的色调映射。     

高动态范围图像全局与局部色调映射的融合

针对高动态范围(HDR)图像显示于普通显示设备的问题,提出一种新的结合全局与局部的色调映射方法,先对高动态范围图像分别进行全局和局部的映射,对所得的图再各自进行曲波分解,然后对分解系数进行加权融合.用5组HDR图进行验证,结果表明:用该方法得到的图像有更好的视觉效果.     

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.     

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.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

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.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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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.