采用噪声自适应正则化的图像重建的仿真研究

针对图像分辨率过低的情况,传统的全局正则化方法未能有效地分辨图像的细节,尤其是图像的边缘问题,根据图像的降质模型,基于正则化方法,并结合降质图像模型,采用迭代的方式确定局部正则化参数代替全局化的正则化参数,提出一种基于噪声的自适应正则化方法的图像重建.再次通过Matlab软件仿真,对比全局正则化和新的基于噪声自适应正则化图像重建的结果,仿真实验证明该方法能够克服传统的正则化方法的局限性,并能够很好地复原图像的边缘细节.     

一种自适应正则化的图像超分辨率算法

提出一种自适应正则化的图像超分辨率重建算法. 首先, 利用局部残差均值自适应地计算各低分辨率图像通道的权值参数矩阵, 可有效地利用各通道对应区域间的交叉信息; 其次, 利用正则项局部误差均值自适应地计算平衡正则项和保真项的正则化参数矩阵, 能较好地保持图像边缘纹理等信息.实验结果表明本文算法不但具有较高峰值信噪比(Peak signal to noise ratio, PSNR) 和结构相似度(Structural similarity, SSIM), 而且在边缘、纹理等细节区域具有更好的重建效果.     

优化加权TV的复合正则化压缩感知图像重建

目的：压缩感知理论突破了传统的Shanon-Nyquist采样定理的限制,能够以较少的采样值来进行原信号的恢复。针对压缩感知图像重建问题,本文提出了一种基于优化加权全变差（Total Variation, TV）的复合正则化压缩感知图像重建模型。方法：提出的重建模型是以TV正则化模型为基础的。首先,为克服传统TV正则化会导致重建图像的边缘和纹理细节部分模糊或丢失的缺点,本文引入图像的梯度信息估计权重,构建加权TV的重建模型。其次,利用全变差去噪（Rudin–Osher–Fatemi,ROF）模型对权重进行优化估计,从而减少计算权重时受噪声的影响。再次,本文将非局部结构相似性先验和局部自回归性先验引入提出的加权TV模型,得到优化加权TV的复合正则化重建模型。最后,结合投影法和算子分裂法对优化模型求解。结果：针对自然图像的不同特性,本文使用复合正则化先验进行建模,实验表明上述重建问题通过我们的方法得到了很好的解决,加权TV正则化先验使得图像的平坦区域和强边重建较好,而非局部结构相似性先验和局部自回归性先验能够保证图像的精细结构部分的重建效果。结论：本文提出了一种新的复合正则化压缩感知重建模型。与其它基于TV正则化的重建模型相比,实验结果表明本文模型的重建性能无论是在视觉效果还是在客观评价指标上都有明显的提高。     

结合非局部低秩先验的图像超分辨重建概率模型

现今图像成像技术日益普及,但受成像设备、成像环境以及在获取图像过程中外界噪声等因素的相互制约,在实际应用中很多图像成像分辨率较低,带来诸多问题.为此,提出一种有效的基于最大后验概率和非局部低秩先验的图像超分辨重建模型.首先,该模型采用连续图像序列作为数据输入,利用单幅图像内与连续图像间的相似性作为先验知识,提升相似图像块匹配度,消除图像细节丢失现象.然后,以最大后验概率框架建模,使用高斯分布和吉布斯分布拟合模型参数,提升模型泛化能力.通过相似块的奇异值估计待求块的奇异值,采用低秩截断抑制重建过程中引入的噪声.最后,利用图像的非局部自相似性和低秩性质,以非局部低秩约束正则化图像重建过程,添加图像的局部和全局信息来提升重建效果.在标准光流数据集、纽约大学和山东省千佛山医院提供的数据集上的实验结果表明,文中基于最大后验和非局部低秩先验的模型与传统插值算法、基于重建的优秀算法相比,在5组仿真实验中,其平均峰值信噪比提升6.3 dB,在保持图像纹理特征和恢复图像细节方面可取得更好的重建性能.     

基于自适应约束正则HL-MRF先验模型的MAP超分辨率重建

针对Huber-MRF先验模型对图像高频噪声抑制能力较差,而Gauss-MRF先验模型对图像高频过度惩罚的问题,提出了一种改进的自适应约束正则HL-MRF先验模型。该模型将Huber边缘惩罚低频函数与Lorentzian边缘惩罚高频函数相结合,对低频进行线性约束的同时对高频实现平滑惩罚;并采用自适应约束方法确定正则化参数,从而得到最优的参数解。与基于Gauss-MRF先验模型和Huber-MRF先验模型的超分辨率算法相比,HL-MRF先验模型获得的超分辨率重建图像在峰值信噪比(PSNR)和细节方面都有一定程度的提高,在抑制高频噪声、避免图像细节被过度平滑方面具有一定的优势。     

正则化技术和低秩矩阵在稀疏表示超分辨率算法中的应用

为了有效地利用图像的特征作为指导重建的先验知识,解决常规超分辨率算法对边缘与结构等细节恢复不足的问题,提出一种改进的超分辨率算法.对待重建图像进行低秩分解,得到不同特征的低秩子图像和稀疏子图像;对于低秩子图像,提出采用基于正则化技术的稀疏表示超分辨率算法进行重建,先通过在低秩子图像中寻找相似图像块构造非局部相似正则化项,得到图像的非局部冗余,以保持边缘信息;再通过局部线性嵌入方法构造流形学习正则化项,获得图像的结构先验知识,以增强结构信息.对于稀疏子图像则不参与稀疏表示超分辨率重建,而是采用双三次插值法进行重建.实验结果表明,与其他算法相比,无论在主观视觉效果上,还是在峰值信噪比和结构相似性指标上,文中算法都有显著的提高.     

基于结构张量的视频超分辨率算法

针对传统正则化超分辨率（SR）重建模型中,正则化参数选择过大会使重建结果模糊,导致边缘和纹理等细节丢失,选择过小模型去噪能力又不足的问题,提出一种基于结构张量的双正则化参数的视频超分辨率重建算法。首先,利用局部结构张量对图像进行平滑区域和边缘的检测;然后,利用差异曲率对全变分（TV）进行先验信息加权;最后,对平滑区域和边缘采用不同的正则化参数进行超分辨率重建。实验数据显示提出的算法将峰值信噪比（PSNR）提高了0.033～0.11 dB,具有较好的重建效果。实验结果表明：该算法能够有效地提升低分辨率（LR）视频帧重建效果,可应用于低分辨率视频增强、车牌识别和视频监控中感兴趣目标增强等方面。     

基于结构相似度的单幅图像正则超分辨复原

图像具有大量的局部结构相似区域,并且这种相似性可以在多个尺度上保持。基于这一特征,利用结构相似指标进行相似性匹配生成相似的低分辨率图像序列,从而把单幅图像的超分辨问题转化为图像序列超分辨问题来解决。文中提出了一种新的自适应的正则化方法,正则参数的选取使得目标函数存在全局最优解。最后证明了算法的收敛性。实验表明,该方法具有很好的复原效果。     

基于压缩感知的自适应正则化磁共振图像重构

当前基于压缩传感理论的正则化磁共振(CS-MR)图像重构算法普遍采用全局正则化参数,不能很好地在保持边缘和平滑噪声方面做出平衡。为此,提出一种自适应的正则化CS-MRI重构算法。结合图像稀疏性和其局部光滑性的先验知识,采用非线性共轭梯度下降算法求取最优化问题,并在迭代过程中自适应地改变局部正则化参数。新的正则化参数可以更好地恢复图像边缘,并且有利于平滑噪声,使代价函数在定义域内具有凸性;同时先验信息包含于正则化参数中,以提高图像的高频成分。实验结果表明该算法能有效权衡恢复图像边缘和平滑噪声两者的关系。     

基于形状自适应非局部回归和非局部梯度正则的深度图像超分辨

针对深度图像分辨率低、深度不连续性模糊问题,提出一种基于形状自适应非局部回归和非局部梯度正则的深度图像超分辨方法。为了探究深度图像非局部相似块之间的相关性,提出了形状自适应的非局部回归。该方法对每个像素点提取其形状自适应块,并根据形状自适应块构建目标像素的相似像素组;然后针对相似像素组中的每个像素,结合同场景的高分辨率彩色图像获得非局部权重,从而构建非局部回归先验。为了保持深度图像的边缘信息,对图像梯度的非局部性进行探究。不同于总变分（TV）正则化对所有像素点梯度的零均值拉普拉斯分布假设,该方法利用深度图像梯度的非局部相似性,用非局部块估计特定像素点的梯度均值,并用学习到的均值来拟合各像素点的梯度分布。实验结果表明,相较于基于边缘不一致性评价模型（EIEM）,所提方法在Middlebury数据集上的2倍和4倍上采样率的平均绝对值差（MAD）分别下降了41.1%和40.8%。     

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