基于Hough算法的图像对称轴检测（英文）

为高精度提取对称刚体对象的中轴线,提出了一种基于Hough变换的图像对称轴检测方法。本文以子弹为研究对象,首先采集原始图像,因刚体边缘是对称轴检测的基础,采用相关的算子进行边缘检测,获得所有可能的边缘点。然后利用测得的所有边缘点,通过Hough变换确定图像所有可能的对称轴,进而得到所有的倾斜角和截距及其范围。最后,利用最小二乘法计算,当刚体一边边缘点关于对称轴的对称点到另一边所有边缘点的最小距离之和为最小时,该对称轴即为最优对称轴,也是被测对象的中轴线。仿真实验结果证明,该算法在一定程度上提高了对称轴检测的抗噪性和精度,对实际工程应用具有一定的价值。     

基于Hough变换实现圆的快速检测方法

为了快速正确的检测出图像中的圆,在传统Hough变换圆检测的基础上,利用圆是中心对称的几何特征,提出了一种新的基于Hough变换实现圆检测的方法,该方法运用Otus阈值分割技术将测试目标从检测图形中分离出来,运用Canny边缘检测器对图像进行边缘检测,检测后对图像进行筛选,排除明显不可能为圆的图形,之后对待检测图形,以过圆心的直线为对称轴对图像上的三点进行对称选取,计算出圆心坐标值和半径值,运用Hough变换在参数空间中对值进行投票,累加计数求出峰值。实验结果表明,该方法降低了计算复杂度和对计算空间的需求,与当前应用最广的RHT,以及SHT圆检测方法相比,运行速度快、精度高,抗噪性能好。     

改进的Hough变换实现圆检测

为了自动检测出图像中的圆并精确测量其参数,提出一种改进的点Hough变换圆检测方法.首先对提取边缘后的轮廓进行一次筛选,得到所有的连续边缘轮廓;然后进行二次筛选,排除那些明显不可能为圆的图形,获得最终候选边缘轮廓.对候选边缘点组进行快速点Hough变换圆检测,计算圆的直径值和圆心坐标值,在检测过程中,采用自适应的点选择步长值和累加器判断阈值.利用VC+ +6.0开发了圆检测系统实验软件,并进行了对比实验,结果表明该方法可以有效解决原算法中固定值导致检测精度不高、误检测和漏检测的问题.     

改进蚁群算法与Zernike矩细分的图像边缘测量方法

针对传统蚁群算法计算耗时、易受噪声影响等缺点,提出一种改进蚁群算法与Zernike矩细分的图像亚像素边缘测量方法。该算法采用二维灰度直方图求解聚类中心、拉普拉斯算子聚类、划分图像边缘点、目标点和噪声点等,利用全局自适应信息素更新方式提取图像边缘,进而通过Zernike矩快速算法细分图像亚像素级别边缘,提高了边缘分割精度。以SKF 32308J2/Q轴承为研究对象,采用该方法检测了轴承图像的内、外圈边缘,并通过最小二乘拟合,采用标准件进行轴承的坐标标定,测量了轴承内、外径等几何参数,将该测量方法与改进Hough变换的测量结果相比较,证明了该算法具有较高的测量精度。     

基于有序Hough变换的快速圆检测算法

针对随机Hough变换（RHT）及其改进算法在同一圆边缘点随机抽样时命中率低且投票处理过程复杂,提出了基于有序搜索的广义Hough变换快速圆检测算法（SQHT）。该算法利用圆的几何性质和梯度方向信息来有序搜索圆边缘点集,将Hough变换的基于投票判定基元参数转变为有效确定基元三点的讨论。执行算法时,首先顺序搜寻第一边缘点并根据邻域边缘点集或图像灰度值计算其梯度值;接着在第一点所在行匹配与其梯度信息相符的第二点,根据前两点信息在第一点所在列匹配第三点;最后按照RHT算法流程确定有效基元参数,从而避免了随机抽样带来的时间不确定性。该算法具有计算速度快,检测时间可控,适用范围广泛,抗干扰性强等特点。相比于RHT算法,提出的算法在单目标圆检测情况下检测效率提高了2倍,在多目标圆（5个及以上）且有非目标边缘点情况下检测效率提高了5倍,在多圆检测方面能有效弥补了Hough变换算法的不足。     

基于Hough变换的角点检测算法

角点检测是图像处理和机器视觉领域中基本而重要的问题。提出了一个基于Hough变换的角点检测算法,通过遍历地考察边缘图像中各像素点的一个邻域窗口,利用Hough变换寻找以窗口中心点为出发点的直线段,并通过这些直线段的数量和相互之间的夹角判断当前中心点是否是角点。针对固定的窗口,使用了模板预先计算及环形缓冲区等技术提高Hough变换及图像遍历的效率。在实际图像库上的对比实验表明提出的算法具有高的角点检测率,最低的角点误检率和角点位置误差,同时相比同样可得到构成角点各边的角度的方法.提出的算法同样具有更高的检测率和精度。对于时间性能要求不高的角点检测应用场合,提出的算法比已有算法具有更优的整体检测性能。     

基于改进Hough变换的圆形零件尺寸测量研究

分析了直方图均衡化图像预处理技术,针对标准Hough变换的不足,提出了一种结合圆的几何特性改进Hough变换的方法。该方法根据圆周上各点连线的垂直平分线交点通过圆心这一圆的几何特性,沿边缘方向进行梯度搜索,找出圆心并求解半径,有效解决了含噪声图像圆形零件边缘检测的难题。通过对轴承零件内、外径和尺寸的测量应用研究,验证了改进Hough变换圆形零件测量技术的有效性和准确性。     

基于机器视觉的液晶显示屏装配尺寸检测算法的研究

提出了一种检测液晶显示区域和外壳之间距离的算法。该算法将霍夫变换与最小二乘法结合,首先,利用Canny算子提取液晶显示区域和外壳的边缘。然后,利用霍夫变换对边缘直线进行粗定位,并依次找到直线边缘附近的所有点集。最后,利用最小二乘法进行拟合,精确地检测出图像中的直线边缘,由此计算出液晶显示区域和外壳之间的距离。实验结果表明,提出的检测算法具有较高的精度与效率,并已应用于产品的在线检测。     

海上监控图像的海天线及其目标区域提取

根据海上监控采集海面图像的特点,提出一种适用于海天线及其目标区域提取的方法。该方法具体是对海面图像灰度化和高斯滤波后,首先根据灰度差异采用OSTU自适应阈值分割方法对海面图像进行分割;接着利用Canny边缘检测得到图像的所有边缘点集,从而获得主要轮廓;然后,根据梯度方向,减少无关边缘点,来改进Hough变换,连接相邻斜率误差小的直线段,减少直线段数目,选取有效程度最大的直线为海天线;最后,依据海天线的位置确定海天线区域。海天线区域的确定,为运动目标的检测、跟踪和避障节约了时间,并减少了误检概率。     

斜拉桥拉索径向畸变CCD图像的边缘检测与图像提取

径向畸变是CCD成像系统中的一种常见现象.提出了一种对斜拉桥拉索径向畸变CCD图像进行边缘检测和图像提取的算法.首先,在图像的预处理阶段,对原始图像进行灰度化和滤波处理.其次,运用边缘检测、边界跟踪及Hough变换获得了拉索轮廓的连续边界.最后,利用原始的灰度图像和基于拉索轮廓的掩模板,获得了无背景的拉索表面图像.该算法在斜拉桥拉索表面伤痕检测中得到应用,结果表明该算法对径向畸变的CCD图像能有效地进行边缘检测和图像提取.     

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....