图像降噪的自适应高斯平滑滤波器

作为去除图像中噪声的图像增强技术,常用的图像平滑方法在提高局部信噪比的同时,也使图像产生模糊。为克服上述缺点,引入了自适应高斯滤波器,它结合了高斯滤波器和梯度倒数加权滤波器的特点,同时考虑了图像局部的空间距离和像素距离,以确定参与局部平滑的像素及其权值。该滤波器算法牺牲了简单平滑滤波器的计算性能,但很好地保留了图像的局部特点,特别是边缘和细节。实验比较了该方法与其他常用滤波器的性能,结果证实了该方法的有效性。     

一种改进的非局部均值图像去噪算法

传统非局部均值滤波算法中使用指数型加权核函数,容易导致图像细节因过度平滑而变得模糊。为此,在指数型加权核函数的基础上,采用余弦系数加权的高斯核函数,设计一种改进的非局部均值图像去噪算法,并将其应用于加权系数计算中。实验结果表明,该算法的去噪性能优于传统算法,且能更好地保留原图像的细节信息,峰值信噪比最大可以提升1.6 dB。     

一种新的电能质量自适应滤波方法*

在电能质量检测中,去噪和保留突变点信息是两个十分重要的问题.为此提出了一种新的基于梯度倒数加权平均算法的自适应滤波方法.该方法首先对电能质量采样信号点建立五个模板,依据检测点与五个模板均值的梯度变化规律,进行突变点判决.在传统梯度法的基础上,选择最佳模板,并用该模板均值与模板内各点幅值的差值代替传统梯度算法中的梯度值,然后对不同类型的点采用不同的算法去噪.实验结果表明,与传统的梯度倒数加权算法和五点均值滤波法相比,改进的算法能够更好地清除噪声,同时较好地保留突变点信息,有针对性地解决了电能质量检测中的两大重要问题.     

融合梯度信息的改进引导滤波

目的 为了有效消除引导滤波平滑图像后产生的光晕现象,提出一种新型的融合梯度信息的改进引导滤波算法。方法 该算法借助引导图像的梯度信息来判断图像边缘位置,并结合指数函数框架设计权值来控制不同图像区域内的平滑倍数,使改进后的引导滤波能够自适应地区分和强调边缘,从而避免边缘附近由于过度模糊所引入的光晕现象。结果 与引导滤波算法相比,本文算法能在保边平滑的同时较好地抑制光晕,并在结构相似性（SSIM）评价和峰值信噪比（PSNR）评价中分别取得最高约30%和15%左右的质量提升。结论 本文算法具有较好的鲁棒性,在图像平滑、图像细节增强、多曝光图像融合等多种图像处理相关应用中均有着良好的表现。     

一种改进的 NAS -RIF 水下图像盲复原算法

提出一种基于空域自适应加权因子的 NAS -RIF 图像盲复原算法,算法通过在原 NAS-RIF 算法代价函数中引入空域自适应加权因子,以改善图像复原的逼真和平滑。实验结果表明,改进后的算法信噪比改善增益可以提高2．39dB,复原后图像细节和清晰度有了一定程度的改善。     

基于DCT系数的自适应误码掩盖算法

提出一种改进的误码掩盖算法,即自适应地选择加权插值和区域匹配方法恢复丢失块.不同于以往只利用平滑性的误码掩盖算法,该算法利用平滑信息和纹理信息,在可用的相邻宏块中基于DCT系数计算能量函数总和,自动分析图像的平滑性和纹理性,然后自适应地选择加权插值或区域匹配的结果恢复丢失块.该算法已在H.264的参考软件JM86上进行实验.实验结果表明,与H.264中只采用加权插值或只采用区域匹配相比,该算法能取得较好的峰值信噪比(PSNR)和主观质量.     

基于改进各向异性的水平集医学图像去噪

针对成像复杂、噪声突出的医学图像在去除噪声的同时模糊边缘特征的现象,提出了基于改进的各向异性的水平集去噪模型。在水平集去噪模型的基础上,加入了改进的各向异性扩散因子,其中改进的各向异性扩散因子采用了中值滤波平滑后的梯度模替换原始图像的梯度模,对于医学图像中大量的斑点噪声更加有效,并保留了图像的边缘信息。基于Matlab平台对改进算法进行了验证,实验表明,基于改进各向异性的水平集算法在有效去除噪声的同时,非但没有模糊边缘特征,相反地起到增强边缘信息的效果。改进算法优于各向异性算法和中值滤波等算法,提高了图像的信噪比,降低了图像的均方误差,保留了更多细节信息,使得医学图像更好地用于诊断,以及后续的分割等处理。     

基于高斯加权和流形的高保真彩色图像降噪

针对用矢量法对彩色图像进行降噪处理,算法复杂度较高,无法达到实时处理的问题,提出了基于改进高斯加权和自适应流形的高保真彩色图像降噪方法。首先,将彩色图像用非局部均值算法得到高维数据,使用改进的高斯内核对彩色图像进行加权计算;然后,采用抛雪球方法处理这些高维数据,以高斯距离为权值,投影每个像素点的颜色到自适应流形;接着,对流形进行平滑降维,采用迭代法实现图像平滑;最后,收集流形中的平滑值,将平滑值对所有像素进行插值,得到降噪后的图像数据。实验证明,该方法对彩色图像进行降噪处理后,能够很好地保留原图像的细节,不会掺杂周围像素的颜色,算法处理速度较快,能够达到实时处理效果,降噪效果与原算法相比峰值信噪比(PSNR)提高近2.0dB,结构相似度提高了1百分点以上。     

一种改进的Canny边缘检测算法

针对带噪声图像,提出了一种改进的Canny算子边缘检测算法。该算法用离散小波变换（DWT）分解和加权重构对图像进行平滑滤波,用Otsu阈值法（最大类间方差法）求出最佳的滞后闽值,在3×3邻域求得梯度法。实验证明,该算法在较好地抑制噪声的同时保留了更多边缘,检测出的图像边缘更加准确和丰富。     

改进的Canny算法及其在图像编码中的应用

分析仅以梯度模值作为依据的Canny边缘检测算法的不足,提出一种以曲率加权梯度模值为判据的改进算法以满足基于边缘信息的图像编码压缩对边缘提取的严格要求。实验结果表明,改进的Canny算法能更有效地抑制对于表征图像对象无重要意义的杂乱边缘,更好地反映图像的结构特征,性能优于现行的Canny算法。     

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.     

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.     

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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