基于像元相互关系的FCM聚类分割算法

针对传统模糊C均值(FCM)算法在图像分割时未考虑像元间的相互关系,且未事先给出初始聚类中心的问题,提出了一种考虑像元间相互关系的FCM聚类分割算法。该算法基于数据场原理,首先利用像元间的相互关系,通过计算各像素点的势值,形成图像数据场,然后利用图像数据场势心,确定FCM算法的初始聚类中心,最后在图像数据场的基础上,利用FCM算法实现对目标图像的聚类分割。利用人工合成图像和工件表面缺陷图像对算法的有效性进行验证,实验结果表明,该算法具有较好的分割效果,且对于条痕、脱碳、孔洞3种缺陷的不同噪声图像分割的正确率均在93%以上,同时具有较高的平均结构相似性。     

一种改进的模糊C-均值(FCM)彩色图像分割算法

针对传统模糊C-均值(FCM)聚类算法计算量大,聚类中心对初始值敏感和聚类数目不能自适应确定的缺点,提出了一种改进的FCM算法。首先对图像进行采样量化,并在满足视觉一致性的L*a*b*颜色空间计算并统计图像的色差信息,然后依据全局色差阈值选取初始聚类中心,对图像进行聚类分析,同时根据准则函数确定最佳聚类数,实现了聚类中心的优化选取和最优聚类数目的确定,有效减少了计算量。研究结果表明,改进后的FCM算法不仅较好地克服了传统FCM算法的缺点,而且聚类效果好,处理速度快,聚类效果与人的视觉感应保持了良好的一致性。     

结合密度峰聚类的K均值图像分割算法

针对K均值聚类算法在图像分割应用中的不足,结合密度峰聚类算法对原有算法进行改进,得到了一种图像分割效果较好的改进K均值算法。K均值算法需要人工指定聚类中心数目,并且聚类中心的随机初始化对最终的图像分割结果有很大影响。针对以上缺点,对K均值算法进行改进,通过密度峰聚类算法自动确定了图像分割的聚类中心数目和较为准确的初始聚类中心。为了衡量色差在人眼中的感知情况,在算法中引入了NBS距离作为距离测度。实验结果表明,改进后的图像分割算法在分割图像时具有稳定的性能和较好的效果。     

基于模糊C均值技术的轴承故障诊断

先利用多小波变换对轴承缺陷图像进行去噪,再利用模糊C均值(FCM)聚类用于灰度图像分割具有简单直观、易于实现的特点,对模糊C-均值聚类(FCM)算法进行改进,并对缺陷图像进行分割,试验结果证明,该方法显著提高了分割速度和精度,受背景、光照、角度、姿态的影响很小,具有较好的鲁棒性,具有一定的使用价值.     

模糊聚类协作区域主动轮廓模型医学图像分割

医学图像分割的研究对于医学影像发展具有重要意义.区域主动轮廓模型(CV)易受目标和背景区域面积比的影响,且对初始位置敏感.针对上述现象,本文提出一种模糊C-均值聚类(FCM)协作改进CV模型的图像分割算法,即FCM-CV算法.首先在CV模型中增加能量权值函数消除面积比的影响,然后用FCM粗分割结果指导设定改进CV模型零水平集的初始位置.实验结果表明,与CV模型和局部二值拟合模型(LBF)相比,FCM-CV算法消除了面积比对分割精度和效率的影响,具有更好的数值稳定性,且对初始位置不敏感,提高了图像分割的准确性.     

基于人工萤火虫的模糊聚类算法研究

模糊C-均值(FCM)聚类算法是数据挖掘中常用的方法之一,但往往受到初始聚类中心影响,收敛结果易陷入局部极小值的问题。该文提出了一种基于人工萤火虫(GSO)的模糊聚类算法(GSFM)。该算法引入了全局寻优能力强的人工萤火虫算法来求得最优解作为FCM算法的初始聚类中心,然后利用FCM算法优化初始聚类中心,最后求得全局最优解,从而有效克服了FCM算法的缺点。实验结果表明,新算法与FCM聚类算法相比,提高了算法的寻优能力,并且迭代次数更少,收敛速度更快,聚类效果更好。     

动态多目标优化的运动物体图像分割

对小区背景下运动物体图像进行分割时多使用单目标或多目标优化方法,这类方法不能有效适应目标的动态变化,因此本文提出一种动态多目标图像分割优化方法。该方法将时间及环境动态因素作为动态因子,利用K均值(KMeans)算法和和模糊C均值(FCM)聚类算法构造多目标函数;结合动态多目标粒子群算法(DMPSO),使用背景差分法定义环境变化规则,实现动态多目标的图像分割。根据DMPSO算法优化后的聚类结果,分别与K-Means和FCM聚类方法得到的结果进行了对比。结果表明,动态多目标优化的Pareto最优解集分布均匀,图像分割准确率可达到95%,对图像识别的准确率可达到90%,具有较高的识别能力,能满足确定背景下运动物体的准确识别。     

空间约束FCM与MRF结合的侧扫声呐图像分割算法

针对侧扫声呐图像斑点噪声强、目标分割困难的问题,提出了一种基于空间约束的快速模糊C均值聚类(SCFFCM)与马尔可夫随机场(MRF)相结合的分割算法。为克服噪声干扰,该算法首先基于贝叶斯最大后验概率理论在非下采样Contourlet变换域去除声呐图像中的强斑点噪声;然后为加快分割速度,提出SCFFCM算法,该算法用于给出一个较好的初始分割;接着由初始分割计算MRF模型的约束场,再根据图像邻域内灰度波动情况自适应更新结合权值,进而求解得到FCM模糊场与MRF约束场的联合场,并基于最大概率准则得到分割结果;最后,采用形态学去除分割结果中的孤立噪点,并完成孔洞填充。对仿真及实际的侧扫声呐图像的分割实验结果表明,所提算法较FCM和现有的一些FCM改进算法有更强的抗噪能力、更高的分割精度以及更快的运算速度。     

模糊聚类算法综述

模糊聚类算法是近年来图像分割技术领域的研究热点之一。本文在对模糊C均值聚类算法分析的基础上,结合目前在图像分割中的应用研究,对模糊C均值聚类算法的有效性进行了比较分析。从隶属度、聚类数和其它方面,评述改进的模糊c均值聚类算法。最后讨论模糊c均值聚类算法目前存在的问题和发展方向。     

多相水平集协同空间模糊聚类图像多目标分割

图像多目标分割的研究对于机器视觉发展具有重要意义。多相水平集模型(Multiphase level set, MLS)对零水平集函数初始位置和噪声敏感,当初始位置不适宜、噪声较大时无法准确分割多目标。针对上述问题,提出一种多相水平集模型协同空间模糊C-均值聚类(Spatial fuzzy C-means, SFCM)的图像多目标分割算法,即SFCM-MLS算法。首先用空间模糊聚类获取图像多目标粗分割结果,然后用粗分割结果定义多相水平集模型的初始水平集函数对图像做精分割。针对人脑磁共振成像(Magnetic resonance imaging, MRI)图像和患有肿瘤的肝脏计算机扫描断层图像多目标分割试验结果表明,与经典多相水平集模型相比,SFCM-MLS算法对初始位置不敏感,提高了图像多目标分割的准确性。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....