基于椭圆拟合的圆的摄像机标定方法

本文提出了基于椭圆拟合的圆的摄像机标定方法。该方法的平面模板要求圆内有3组两两正交的直径,从3个或多个不同的方位摄取平面圆模板的图像。通过非线性的最小二乘的椭圆的拟合,得到精确的椭圆边界,从而精确定位模板中的特征点,进一步提高摄像机的标定精度。真实图像实验表明,该方法易于实现,精度较高,稳定性较好。     

等边三角形确定摄像机内参数的线性方法

本文提出了一种求解摄像机内参数的线性方法。首先通过空间平面上等边三角形的边计算灭点坐标，根据摄影变换的交比不变性，由拉盖尔定理及三角形的两边夹角计算出圆环点坐标。图像圆环点坐标方程构成内参数约束方程，从而计算出所有内参数。实验结果表明，该方法有较好的灵活性和较高的鲁棒性。     

盾构机姿态参数测量技术研究

根据三点决定一个平面的原理,通过在盾构机中体上布置测量控制点,对其三维坐标进行测量;根据空间解析几何原理,推导出盾构机刀盘中心三维坐标以及俯仰角、横摆角、扭转角的计算方法。文章利用计算机的伪随机函数对盾构机姿态参数的测量精度进行了模拟评价,探讨了提高测量精度的方法。结果表明,盾构姿态参数的测量误差均服从正态分析;采用精度为3mm的激光经纬仪测量控制点坐标,得到的盾构姿态参数的误差范围比规范要求小得多。     

GPS点的测量及其数据处理研究

在一个新的项目要开工之前,全线要进行一下对已交桩的GPS(Global Position System)点进行复测,复测时尽量用GPS仪器重新进行全线的平面控制,核实一下交桩的GPS点是否满足施工精度要求。如为了节省前期复测时间,直接用全站进行线路闭合测量,如果测量的闭合差满足施工要求;同时,也可以认为业主所交桩的点是可以使用。但因为种种原因,如点埋设的时间较长、一致,使点发生沉降和平移、GPS点的坐标给错、或现场的GPS点丢失或点被损坏,这样会导致测量的结果与交桩所给的坐标存在一些误差甚至一些点的坐标不正确,为了使项目测量工作能顺利进行和对施工控制点坐标进行合理的修正。我们有必要用GPS仪器对交桩点进行重新测量,也可以顺便加密一下原来交桩GPS点平面控制网,并且能重新补上被损坏和丢失的GPS点。在国外进行GPS点测量后的想法和见解,希望能给相关测量人员提供一些帮助,也请有测量经验的人提出一些修改意见。     

基于信息扩散估计的平面坐标转换研究

基于最小二乘原理进行坐标转换时,若联测点存在粗差,模型转换参数将会受到污染,降低解算精度。针对传统平面转换模型抗差能力弱的不足,本文采用信息扩散原理估计坐标转换参数,建立基于信息扩散原理的坐标转换模型。实例证明,该方法能够有效地抵抗外界粗差的影响,具有一定的可行性。     

基于主动视觉的摄像机线性自标定方法

为了解决传统摄像机标定方法的精确度差和使用不方便,本文提出了一种基于主动视觉的摄像机线性自标定方法,该方法通过控制摄像机做一次纯轴向运动来确定主点坐标,再做一次纯旋转运动利用单应性矩阵与旋转矩阵的关系确定摄像机的其他三个内参数。这种基于主动视觉的自标定方法原理简单、实现方便、可操作性强。实验结果表明,该方法能够比较准确地标定出摄像机的所有内参数。摄像机标定是计算机视觉中的一项基本任务。传统的标定方法是通过结构的物体(如标定块,标定板等)在图像中的投影计算摄像机的内参数。但是这种方法必须要有标定物,在很多实际应用中难以实现。为了解决传统摄像机标定方法的精确度差和使用不方便,     

复杂背景下目标的快速识别方法

复杂背景下目标的识别是自动跟踪测量系统中的关键技术,识别算法的优劣直接影响了目标识别的精度与速度。针对空中目标成像,由于大气湍流等因素的影响,CCD图像中的光斑通常呈不规则形状,而传统的模板匹配法与圆拟合法在识别不规则光斑时存在不足。本文利用光斑在像平面上的空域分布特性,提出一种基于空域相关程度排序的识别算法,配合经过改进的高效图像处理方法,实现了多个不规则光斑的快速识别。实验结果表明该方法能够在混有多个假目标的图像中有效识别出真实目标并进行跟踪测量。     

巧卸轴承圈

根据实践,可以用以下方法很方便地拆下用普通工具难以拆下的轴承内、外圈。（１）拆外圈用４５＃钢制作如图１所示的圆环,其外径比外圈的内径小０．１～０．２ｍｍ,内径为１６ｍｍ,厚度尺寸与外圈厚度相同。在圆周上间隔９０°打４个孔,孔径比该轴承的钢球大０．１０～０．２０ｍｍ。另配４个圆柱销３（图２）,其直径比圆环上的（４个）孔径小０．０６～０．１０ｍｍ,４个圆柱销长度要相等。拆卸时,按图２所示在圆环的４孔内涂塞润滑脂,以粘住将放入孔内的圆柱销及钢球,由外向内放入圆柱销３及本轴承的或尺寸相同的钢球４。将圆…     

卧式加工中心利用红外测头实现自动找正

卧式加工中心工件平面校正,找工件孔心或外圆圆心建立XY零点,通常方法比较费时,如运用雷尼绍测头校正工件平面和寻找孔心,可以实现工件自动找正、自动建立坐标零点,省去人工找正的繁杂,免去人为误差,大幅提高了找正的效率。其方法主要是利用红外测头测碰采点,并根据测碰点的机械坐标数据进行计算,得出工作台偏转角度和各轴零点位置,最后写入零点偏置表而实现零点设置。     

基于室内大空间消防系统的三目定位法的研究

受国内经济飞速发展及中国制造2025战略需要,室内大空间消防设备备受各行各业青睐。双目定位系统无法有效响应较大室内空间的应用需求,因此需要对三目立体定位的室内大空间标定与优化方法进行相关的研究。首先通过通过坐标矩阵转换,对物项在空间点坐标、图像点坐标进行运算,得到物项在空间中的具体布置,通过得出三目定位系统结构参数与分析数学模型,建立三目立体定位系统,并将将结构参数与测量精度数学模型内分析,同时给出了用于大空间室内消防的三目定位烟雾报警器模型。     

一种基于主动视觉的非线性摄像机自标定

针对计算机视觉摄像机镜头畸变对精度的影响问题,提出了一种非线性摄像机标定方法。该方法是将非线性模型视为线性模型和畸变项的叠加,然后在主动视觉下利用线性模型下的正交运动的FOE(当物体或摄像机做纯平移运动时图像对应点连线的交点)点的关系,给出非线性模型参数的约束方程,从而实现非线性模型的摄像机自标定。模拟和真实图像实验均表明,该方法是有效的,具有一定的实用价值。     

Geodesic normal distribution on the circle

This paper is concerned with the study of a circular random distribution called geodesic normal distribution recently proposed for general manifolds. This distribution, parameterized by two real numbers associated to some specific location and dispersion concepts, looks like a standard Gaussian on the real line except that the support of this variable is [0, 2π) and that the Euclidean distance is replaced by the geodesic distance on the circle. Some properties are studied and comparisons with the von Mises distribution in terms of intrinsic and extrinsic means and variances are provided. Finally, the problem of estimating the parameters through the maximum likelihood method is investigated and illustrated with some simulations.     

Fitting circles to scattered data: parameter estimates have no moments

We study a nonlinear regression problem of fitting a circle (or a circular arc) to scattered data. We prove that under any standard assumptions on the statistical distribution of errors that are commonly adopted in the literature, the orthogonal regression estimators of the circle center and radius have infinite (absolute) moments. We also discuss methodological implications of this fact.     

Statistical analysis of Fourier coefficients in a restricted harmonic dial

Due to the physical nature of certain periodic data, the harmonic dial points (the Fourier coefficients obtained from harmonic analysis of the data) are sometimes restricted to circular regions in the dial plane. It is proposed that a circular normal distribution (CND) truncated outside a circular region be used to describe the probabilistic behavior of the random phenomena. Recurrence relations for the population moments of a CND truncated outside a circular region are derived. These recurrence relations are used to obtain consistent asymptotically (jointly) normal estimators of the unknown parameters of the distribution. A numerical example based on the harmonic dial points representing the 27-day recurrence tendency of the daily international magnetic character-figureC _i is given to illustrate the theory.     

Data depth for simple orthogonal regression with application to crack orientation

This paper studies tangential and simplicial data depth for simple orthogonal regression. Given N points in the plane, simple orthogonal regression means that we wish to determine the line through the origin that has smallest distance to the points measured in the direction orthogonal to the line. For both depth notions, it is proved that two lines which are orthogonal to each other, i.e. two lines forming a cross, have the same depth. Depth-based orthogonal regression can thus merely fit crosses, not lines. We investigated the robustness properties of maximum depth estimators using the notion of exact fit. Another topic the paper covers is the testing of the hypothesis that the data points form a cross-like pattern. After a simple transformation, such a test can be based on the biggest data depth. The paper discusses an application of this test for the investigation of stress fractures in materials.     

神华集团实施循环经济产业化的发展路径分析

本文运用案例研究方法,以神华集团为研究对象,指出以企业集团为载体推动循环经济产业化发展是继以单个企业为载体的清洁生产路径,以多个彼此产权独立企业为载体的工业生态园、绿色供应链等路径之后,中国循环经济产业化发展的又一条新路径。企业集团是中国实施循环经济产业化发展的较好载体,首先通过企业集团的产权关系纽带可以建立稳定的循环...     

Estimating the Weight Undersize Distribution for the Wicksell problem

In Wicksell's corpuscle problem one is interested in estimating the distribution of sphere diameters from the diameters of circle profiles obtained by a random section of the body containing the sphericle particles. The problem is known to be an ill posed inverse problem. Several regularization techniques have been applied to find solutions. We will review some of these in this article. In practical situations one often is more interested in the distribution of weight rather than the distribution of diameters. In estimating the weight undersite distribution similar problems are encountered. We will consider an estimator that is obtained by smoothing the distribution function of the circle diameters locally. It will be shown how the bandwidth must be chosen to obtain consistency and mean square error optirnality. Also asymptotic normality will be shown.     

由劣弧测量而引出的一种新的描述及评价测量的方法

大半径小圆弧因可测量的圆弧段太短,会把测量误差放大,从而影响评价结果,引起单一的圆心和半径难以确定。本文讨论了如何在逻辑上避免此问题,并且提出一种新的描述及评价测量的方法。     

Density estimation for randomly distributed circular objects

Summary Nearest neighbour methods traditionally used to estimate density of a sessile biological population treat individuals as points. The present paper suggests distance-based density estimators which treat individuals as circles with variable areas. Distribution of distance between a sample point and thek-th (k = 1, 2, 3, …) nearest circle is derived. Maximum likelihood estimator of density is obtained from a random sample of point tok-th order distances. Assuming a skewed distribution for the circle radius, moment estimators of density and mean circle area are derived.