Prewitt图像边缘检测及边缘细化的FPGA实现

针对实时图像处理的要求,使用FPGA对图像数据流进行在线Prewitt边缘检测。针对传统算法需要人工给定阈值和产生的边缘较宽的不足,用基于FPGA的自适应阈值算法和非极大值抑制方法对边缘检测的结果进行细化处理,提高了边缘检测的精度。     

基于改进Canny算子的煤矿井下物体图像边缘检测方法研究

针对传统的Canny 算子检测井下物体低强度边缘能力不足的问题,提出了一种改进的边缘检测算法。该算法从以下三个方面进行改进：（1）采用一种新的四阶偏微分方程的降噪算法对图像去噪,进一步提高降噪效果,且在降噪过程中较好地保留图像细节,使井下物体更容易被检测。（2）采用自适应阈值的方法对图像边缘进行检测,实现了双阈值的自适应提取,能够较好地提取真实边缘。特别是在低对比度图像的边缘提取上,此方法更具有优势。（3）基于模糊判决的理论,在传统的Canny算法的基础上提出了一种有效的边缘连接方法。为了验证Canny边缘检测算子的效果,分别用Prewitt 、Robert 、Sobel、传统的Canny算子对井下图像进行边缘检测实验,结果表明,该方法在最大程度抑制噪声的同时,能检测到更多的低强度边缘,为井下煤矿探测机器人图像辨识奠定了基础。     

限制型自适应SUSAN边缘检测算法

对于边缘检测中传统SUSAN(smallest univalue segment assimilating nucleus)算法,固定门限会将非边缘点划入核值相似区(univalue segment assimilating nucleus, USAN),并经过单一阈值判断,非边缘点易被误判为边缘点,导致算法的低鲁棒性.针对此问题,提出了结合自适应门限算法和阈值选择策略的限制型自适应SUSAN算法.首先,分析SUSAN算法优缺点,根据USAN特点以及同异侧噪声容忍度范围设置阈值选择策略,减少误判并提高噪声鲁棒性;然后采用与USAN内像素值正相关的自适应门限算法,进一步增强边缘检测能力.在标准测试图像以及不同类型噪声的经典灰度图中实验结果表明,相比于传统SUSAN算法和Canny, Prewitt, Sobel, LoG, Roberts等边缘检测算法,该算法在客观图像评价指标FSIM值,PFOM值和准确率上均高于其他算法;而在主观视觉上,在无噪条件下能够更好地抑制纹理区域像素干扰,检测边缘更完整丰富.特别是在大量噪声干扰导致其他算法均失效的情况下,该算法在抑制噪声的同时,仍能有效地检测出图像边缘.     

一种改进的Canny边缘检测算法

针对噪声对图像边缘检测的影响,为抑制虚假边缘,提出了一种改进的Canny边缘检测算法。该算法首先采用分数阶差分方法来计算梯度,同时利用相邻像素的梯度及其梯度差两种信息来改进非极大值抑制过程,最后通过迭代计算的方法,自适应确定梯度图像的分割阈值。试验结果表明,改进算法的抗噪声性能与传统的Canny边缘检测算法相比有明显优势,提高了图像边缘检测的准确度。     

一种基于Canny理论的自适应边缘检测方法

基于Canny算子，提出了一种Canny自适应的边缘检测方法。Canny自适应算法在保持了Canny算子原有的定位准确，单边响应和信噪比高等优点的基础上，提高了Canny算子在提取图像边缘细节信息和抑制假边缘噪声方面的性能。Canny自适应算法将整幅图像分割为若干子图像，并根据各子图像的边缘梯度信息，结合全局边缘梯度特征信息自适应地生成动态阈值，提高了边缘检测的自动化程度，在实际的应用中获得了很好的效果。通过数学分析和试验结果证明了Canny自适应算法是一种有效的边缘检测改善方法。     

服装人台建模中的视觉图像人体轮廓细化提取

在个性化的服装人体三维图像测量技术中,人体边界识别需要得到准确的单像素级细化轮廓。在综合采用多尺度小波变换进行图像灰度的阶跃型突变点检测基础上,对小波模极大值的直方图均化处理以自适应地选取双阈值,通过抑制非极大值点对边缘线细化,并利用双阈值跟踪连接边缘点,从而得到单像素级的人体轮廓图像。对人台图像的实验证明了算法的可行性和有效性。     

基于边缘差分的运动目标检测方法

针对视频序列中的运动目标检测问题,提出了一种新的基于边缘差分的运动目标检测方法.通过改进的边缘检测算法提取视频序列中相邻帧的边缘图像并作差分,采用改进的Otsu法对差分图像进行阈值分割,得到运动目标检测的结果.结合Prewitt算子和Sobel算子改进的边缘检测算法能够获取纹理丰富、细节显著的边缘图像,边缘差分结果更加理想;改进的Otsu法联合类内方差能够很好地抑制噪声,保留更多的纹理细节.实验结果表明,提出的方法能够提取更加完整的目标区域,对背景噪声更加鲁棒.与最近一些同类算法相比,在背景运动和光照变化条件下,该方法具有更加优越的运动目标检测性能.     

基于改进Canny算法的噪声图像边缘检测

针对传统Canny边缘检测算法对噪声图像的去噪效果不佳,以及双阈值需要预先设定的问题,提出了一种基于改进Canny算法的噪声图像的边缘检测。首先构建自适应高斯滤波器对曲度算子进行改进,得到优化的二值边缘图;然后基于最大类间方差法构建了灰度梯度映射函数,确定最佳的双阈值;最后对二值边缘图进行双阈值检测以及边缘连接。实验结果表明,改进算法与现有Canny算法相比,在不同类型噪声和不同浓度噪声的环境下,改进算法提高了对噪声图像边缘检测的性能,其中PSNR值平均提高了1.9%,MSE值平均降低了1.6%,且具有自适应性强、运行效率高的优点。     

结合小波滤波和形态学的图像边缘检测方法

针对传统的边缘检测方法对含噪图像检测效果不理想,提出了一种小波滤波和多结构元素的数学形态学相结合的图像边缘检测方法。用广义交叉验证准则进行小波阈值的自适应选取,用此阈值的广义阈值函数的小波滤波方法对含噪图像去噪;构造4种具有代表性的结构元素,根据边缘方向自动选择相应方向的结构元素,用改进的形态学边缘检测算子对图像进行边缘检测,得到在噪声存在条件下较为理想的图像边缘。实验结果表明,该算法能够有效地抑制噪声,检测的边缘较清晰、连续,其检测效果优于传统边缘检测算法。     

基于分形特征和阈值分析的图像边缘检测

针对传统的边缘检测算法对噪声敏感且伪边缘较多,提出一种基于分形特征和阈值分析的图像边缘检测方法。该方法利用改进的毯覆盖算法计算出图像的分形特征,将图像的灰度分布映射到分形维数空间上,再根据提取的分形特征图进行阈值分析,获得高低两个阈值,将像素值分为非边缘、弱边缘和强边缘3类,再对弱边缘像素进一步加以判断。实验结果与其他算法相比较表明,该算法检测出来的图像边缘伪边缘和噪声最少。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

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.     

Call for papers Special issue on Modeling and control technologies for civil,energy,and power systems

正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control     

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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 and promote academic exchange between Chinese and foreign scientists everywhere.