共查询到20条相似文献,搜索用时 31 毫秒
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L. Li 《Opto-Electronics Review》2012,20(2):120-125
In this paper, an accurate 3D model analysis of a circular feature is built with error compensation for robot vision. We propose
an efficient method of fitting ellipses to data points by minimizing the algebraic distance subject to the constraint that
a conic should be an ellipse and solving the ellipse parameters through a direct ellipse fitting method by analysing the 3D
geometrical representation in a perspective projection scheme, the 3D position of a circular feature with known radius can
be obtained. A set of identical circles, machined on a calibration board whose centres were known, was calibrated with a camera
and did the model analysis that our method developed. Experimental results show that our method is more accurate than other
methods. 相似文献
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Yaxiong LU 《Chinese Journal of Lasers》1992,1(2):117-123
The characteristics of an axially-asymmetric optical resonator(AAOR)areanalysed by using the variable reference plane method.The positions of the beam waist andthe plane wavefront are obtained.The variation of the beam size ellipse and wavefront curva-ture ellipse are also discussed. 相似文献
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本文使用转移矩阵的方法,引入椭圆角转换函数,使椭圆问题得到简化,推导出十分简单的切延迟椭圆反射的迭代公式,这样非常有利于理论分析.切延迟椭圆反射腔映射系统(TD-ERCS)在切延迟1单位时存在吸引子,利用该公式,对其吸引子形成的原因及稳定性做了理论分析,发现圆的吸引子与椭圆不尽相同;同时发现椭圆有两个不动线,但只有一个是稳定的.本文还发现,随着椭圆压缩因子μ的减小,对于任意的切延迟因子m,相邻两次迭代数据间的相关性增强,这说明将该系统用作密码系统,椭圆压缩因子μ不能太小,同时混沌系统本身要求μ不能太大,否则降低安全度.
关键词:
混沌
切延迟
TD-ERCS
吸引子 相似文献
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用黑斑的椭圆性质在二值化图像中探测眼睛 总被引:3,自引:0,他引:3
在人脸探测过程中 ,双眼的探测非常重要 ,这是因为人的眼睛是人脸上最容易探测到的特征部位。通过双眼探测还可以对人脸进行定位 ,使人脸的尺寸归一化。探讨了一种基于二值化图像中黑斑几何形状分析的双眼探测方法。因为人眼的形状比较接近椭圆 ,故在研究黑斑的几何性质时 ,重点研究黑斑的椭圆性质。所谓黑斑的椭圆性质是指按照黑斑的面积和二阶矩计算出的椭圆参数。椭圆的主要参数有椭圆的面积、质心、长短轴的长度和方向角 (椭圆长轴与水平方向的夹角 )。为了描述黑斑与椭圆的近似程度 ,定义了椭圆硬度的概念。根据眼睛黑斑椭圆参数的测试数据建立了探测眼睛的数学模型 ,并给出了根据此模型得到的双眼探测的实验结果 相似文献
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光学测量中椭圆圆心定位算法研究 总被引:9,自引:1,他引:8
提出了一种椭圆圆心定位算法。先对图像中的椭圆目标进行粗定位,获取椭圆的粗定位信息,再用Canny算子对图像中的感兴趣区域进行边缘检测。根据椭圆的粗定位信息以及图像的边缘灰度分布特征,用高斯曲线拟合的方法求得精确的亚像素边缘点的坐标。针对亚像素边缘点中出现的“孤立点”以及噪声点,分别用曲率滤波和均值滤波的方法加以滤波,将滤波后的亚像素边缘点用最小二乘法加以拟合,求得精确的椭圆圆心数据。实验证明了该算法的定位精度和抑制噪声能力,通过测试算法运行时间,证明该算法具有很好的实时性。 相似文献
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Ellipse detection and phase demodulation for wood grain orientation measurement based on the tracheid effect 总被引:2,自引:0,他引:2
The methods of ellipse detection and phase demodulation for determining wood grain orientation are proposed. These methods are based on the tracheid effect—laser beam impinging upon a wood surface forms an elongated laser spot with its direction indicative of the grain orientation. Experimental results show that the method of ellipse detection is suitable for the grain orientation measurement on planed softwood surfaces, while the method of phase demodulation is capable of extracting the grain orientation precisely from laser images with low signal-to-noise ratio, such as the images on the surfaces of hardwood species or roughsawn materials. 相似文献
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为了克服椭圆检测过程中对椭圆完整性和边缘梯度信息依赖性较强的缺点,实现椭圆目标的快速有效检测,提出了一种新的基于弧段提取的椭圆拟合方法。首先将梯度方向符号相同的相邻边缘点连接成弧段,然后根据弧段的凸性和象限分类组成包含三段弧的弧组,定义了新的弧选择策略,利用位置约束和弧对的椭圆中心估计提取候选椭圆,最后采用改进的拟合算法拟合椭圆。实验结果表明,基于弧段提取的椭圆拟合方法相对于LMEDS算法和RHT3具有更好的准确性、鲁棒性和稳定性,实时性也有一定的提高。 相似文献
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For vision measurement in the center circle landmark location problem, an improved center of the ellipse based on Zernike moments sub-pixel positioning algorithm was proposed. First, using Sobel operator edge of the image pixel level positioning and then use the constructed Zernike moments to solve the model, combined with Zernike orthogonal polynomials and completeness and plural moment magnitude rotational invariance calculated edge sub-pixel position; followed by analysis of the principle deviation generated by the moments template and ideals model, a correction formula was proposed to compensate and improved edge criterion used to image sub-pixel edge positioning; finally, using the least-squares ellipse fitting algorithm fitting circle center, reverse edge point, filtered residuals larger point, and then precise positioning of the ellipse center. The experimental results show that this method has good stability and high positioning accuracy can be efficiently used in many applications. 相似文献
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A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error is less than 0.4 pixel. 相似文献
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基于数字信号处理中的IIR理论,提出了一种基于MGTI型interleaver的新颖设计方法,可以简便地得到所求的各组结构参量.通过z变换简化透射方向和反射方向光波电矢量的表达式,分析了零极点位置对整个滤波器的影响,利用IIR中椭圆滤波器的设计方法得到Gires Tournois腔的腔长、臂长差和Gires Tournois腔各镜面的反射率.并给出了利用两个双镜Gires Tournois腔替代两面全反镜所得到的三组不同参量,比较了采用不同Gires Tournois腔所得到的相应的1、3、5、7、9阶interleaver的模拟仿真结果. 相似文献
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Shuzhi Liao Huiying Zhou Zhouan Zhou Haowen Xie Yifang Ouyang Bangwei Zhang 《Indian Journal of Physics》2011,85(2):261-270
Based on the same method by us which describes the solid solubilities of the binary nontransition metal based alloys, the
solid solubilities at room temperature in 1380 binary alloys which are based on the 23 transition metals (Sc, Ti, V, Cr, Mn,
Fe, Co, Ni, Y, Zr, Nb, Mo, Ru, Rh, Pd, La, Hf, Ta, W, Re, Os, Ir and Pt) of the fourth, fifth and sixth long periods have
been studied in this paper. It has been found that the soluble elements can be separated from the insoluble elements by an
ellipse equation (x−m)
2/c
2+(y−n)
2/d
2 = 1, by using a criterion of 0.5at% solubility at room temperature for every host element. The results show that the overall
reliability for the ellipse equation is up to 90% for the 1380 alloys, which indicates the theoretical results are very good
in agreement with the experimental data. The parameters m, n, c and d in the ellipse equation can be explained by the appropriate
parameters for every host metal. 相似文献
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折反射全向相机镜面位姿的自标定方法 总被引:2,自引:1,他引:1
在已知镜面和透视相机参数的情况下,提出一种不需要任何其他标定物的折反射全向相机镜面位姿的自标定算法,只需要折反射相机采集任意一幅图像即可估计出反射镜面与透视相机之间的旋转和平移。利用镜面外边缘所成的像,通过平面圆位姿估算方法获得两个候选位姿;再利用透视相机镜头边缘的成像,同时进行镜头边缘参数估计和镜面位姿选择。该标定方法操作简单,精度高,适用于非单视点相机的标定。仿真和真图实验结果证明了该方法的有效性。 相似文献
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We present a method for measurement of thickness of transparent oil film on water surface based on laser trigonometry. With an oblique incident mode of single-point laser triangulation ranging system, laser light is incident on the upper and lower surfaces of the oil film being measured and an ellipse light spot is formed on the upper and lower surfaces of the oil film. The two light spots are imaged on an image plane CCD by an imaging lens and the image spot is formed and stored in a computer. The thickness of oil film being measured can be obtained by displacement of the image spot and the configuration parameter of the imaging system. The experiment is conducted using edible peanut oil and diesel oil. The research results show that the method presented in this paper is feasible and applicable to dynamic on-line measurement of oil film thickness of oil spill on sea surface. 相似文献
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We propose a method of extracting the true length of a line and an ellipse with two axes from the width of envelopes in the parameter domain. We performed computer simulations and, using a Hough transform computer generated hologram filter, also performed optical experiments. Our experimental results were very similar to those of the simulation. 相似文献
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The critical points of generic paraxial ellipse fields consist of singular points of circular polarization, called C -points, and azimuthal stationary points, i.e., maxima, minima, and saddle points. We define these stationary points here and review their properties. The sign rule for ellipse fields requires that the sign of the singularity indices I(C)=+/-1/2 of the C -points on non-self-intersecting lines of constant azimuthal ellipse orientation (modulo pi/2), i.e., a -lines, alternate along the line. We verify this rule experimentally, using a newly developed interferometric technique to measure C -points and a -lines in an elliptically polarized random optical field. 相似文献