共查询到20条相似文献,搜索用时 15 毫秒
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为了满足现代武器装备对图像跟踪系统的实时性和跟踪可靠性的双重要求,针对武器装备所跟踪目标的特点,将基于分形几何的边界提取方法用于图像跟踪系统,提出了一种基于运动区域和边界图像的目标跟踪方案。文中的边界提取方法不仅能提取出目标的轮廓,还能较好地保留其内部细节,这样通过模板匹配得到的最佳匹配位置更加可靠。同时,基于运动区域的边界提取,尤其是对于远景的目标跟踪大大减少了计算量。此外,在利用边界图像进行匹配的基础上,采用了自适应模板更新策略,目的是尽可能地克服形变、光照等影响,使跟踪过程准确可靠。仿真实验表明,该方法运算量小,能满足武器装备实时性要求。 相似文献
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The use of eye movement as a biometric is a new biometric technology that is now in competition with many other technologies such as the fingerprint, face recognition, ear recognition and many others. Problems encountered with these authentication methods such as passwords and tokens have led to the emergence of biometric authentication techniques. Biometric authentication involves the use of physical or behavioral characteristics to identify people. In biometric authentication, feature extraction is a very vital stage, although some of the extracted features that are not very useful may lead to the degradation of the biometric system performance. Object selection using eye movement as a technique for biometric authentication was proposed for this study. To achieve this, an experiment for collecting eye movement data for biometric purposes was conducted. Eye movement data were measured from twenty participants during choosing and finding of still objects. The eye-tracking equipment used was able to measure eye-movement data. The model proposed in this paper aimed to create a template from these observations that tried to assign a unique binary signature for each enrolled user. Error correction is used in authenticating a user who submits an eye movement sample for enrollment. The XORed Biometric template is further secured by multiplication with an identity matrix of size (n × n). These results show positive feedback on this model as individuals can be uniquely identified by their eye movement features. The use of hamming distance as additional verification helper increased model performance significantly. The proposed scheme has a 37% FRR and a 27% FAR based on the 400 trials, which are very promising results for future improvements. 相似文献
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分形理论在物理实验教学中应用的探索 总被引:3,自引:2,他引:1
综述了作者近年来将分形理论引入基础物理实验教学中的尝试与实践,介绍了分形维数的测定方法及其应用,阐述了教师参与适量的科学研究是实现基础物理实验教学现代化的重要保证。 相似文献
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一种基于分形维数聚类的分形图像编码方法 总被引:1,自引:0,他引:1
对分形维数进行了探讨 ,提出了用分形维数对domainblocks进行聚类 ,从而达到了快速搜索编码的目的。实验结果表明 :与经典分形方法相比 ,在图像保真度基本接近的前提下 ,编码速度提高了 80倍左右 相似文献
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Some results on the behavior and estimation of the fractal dimensions of distributions on attractors
C. D. Cutler 《Journal of statistical physics》1991,62(3-4):651-708
The strong interest in recent years in analyzing chaotic dynamical systems according to their asymptotic behavior has led to various definitions of fractal dimension and corresponding methods of statistical estimation. In this paper we first provide a rigorous mathematical framework for the study of dimension, focusing on pointwise dimension(x) and the generalized Renyi dimensionsD(q), and give a rigorous proof of inequalities first derived by Grassberger and Procaccia and Hentschel and Procaccia. We then specialize to the problem of statistical estimation of the correlation dimension and information dimension. It has been recognized for some time that the error estimates accompanying the usual procedures (which generally involve least squares methods and nearest neighbor calculations) grossly underestimate the true statistical error involved. In least squares analyses of and we identify sources of error not previously discussed in the literature and address the problem of obtaining accurate error estimates. We then develop an estimation procedure for which corrects for an important bias term (the local measure density) and provides confidence intervals for. The general applicability of this method is illustrated with various numerical examples. 相似文献
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利用2维Weierstrass带限函数建立了模拟粗糙海面形状的模型,讨论了分形维数、频率幅度尺度因子等分形参数对海面形状的影响。以粗糙海面形状模型为基础,针对模拟的分形海面形状,从亥姆霍兹积分出发,利用基尔霍夫近似推导出2维分形海面的电磁散射系数,并进行了数值模拟。对微波电磁散射特性随分形维数、频率幅度尺度因子、入射波入射角变化的规律做了进一步讨论分析。在低掠射角时电波会受海面的遮挡,用遮挡函数对散射系数进行修正。研究表明:随着分形维数的增大,散射峰分布变均匀。频率幅度尺度因子越大,散射也越分散。随着入射角的增大,后向散射也逐渐增强,而前向散射逐渐减弱。 相似文献
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ZHAO YuXin YI ShiHe TIAN LiFeng HE Lin & CHENG ZhongYu College of Aerospace Material Engineering National University of Defense Technology Changsha China 《中国科学G辑(英文版)》2008,51(8):1134-1143
Flow visualization of supersonic mixing layer has been studied based on the high spatiotemporal resolution Nano-based Planar Laser Scattering(NPLS) method in SML-1 wind tunnel. The corresponding images distinctly reproduced the flow structure of laminar,transitional and turbulent region,with which the fractal measurement can be implemented. Two methods of measuring fractal dimension were introduced and compared. The fractal dimension of the transitional region and the fully developing turbulence region of supersonic mixing layer were measured based on the box-counting method. In the transitional region,the fractal dimension will increase with turbulent intensity. In the fully developing turbulent region,the fractal dimension will not vary apparently for different flow structures,which em-bodies the self-similarity of supersonic turbulence. 相似文献
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研究了粒子在RIKEN介观器件中的输运性质, RIKEN器件的理论模型是二维Sinai台球的一种, 是研究粒子逃逸曲线混沌性质和分形规律的理想模型之一. 采用逃逸曲线定性比较和分形维数定量计算两种方法, 得到了开口宽度、腔长、拐角位置、圆弧半径等器件参数对逃逸曲线混沌区域分布的影响规律. 结果发现逃逸曲线中存在分形自相似结构, 揭示了粒子在RIKEN介观器件腔中输运过程存在的混沌性质, 并首次运用"眼式结构"分析和相似比比较等方法对分形自相似结构进行了验证.
关键词:
介观器件
混沌性质
分形自相似
分形维数 相似文献
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涡旋轴对称化是影响热带气旋预报的重要动力学过程.截止目前的研究,均用等值线图形主观识别涡旋轴对称化.本文用一个准地转无幅散的正压涡度方程模式,数值积分48h,模拟了初始非轴对称涡旋演变为轴对称涡旋的轴对称化过程.根据模式输出数据,计算了逐时涡旋外缘线的分形维数DB,用分形维数DB的逐时变化客观表征涡旋轴对称化.在此基础上,计算了分形维数De与热带气旋尺度参数R。和热带气旋强度参数Vmax的相关系数.结果显示,DB与Rm的相关系数为-0.70,DB与Kmax的相关系数为-0.75,相关均显著.用此途径,客观表征了涡旋轴对称化与热带气旋参数的联系.结果在热带气旋预报中有应用前景. 相似文献
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R. Rammal 《Journal of statistical physics》1984,36(5-6):547-560
We consider some statistical properties of simple random walks on fractal structures viewed as networks of sites and bonds: range, renewal theory, mean first passage time, etc. Asymptotic behaviors are shown to be controlled by the fractal (¯d) and spectral (¯d) dimensionalities of the considered structure. A simple decimation procedure giving the value of (¯d) is outlined and illustrated in the case of the Sierpinski gaskets. Recent results for the trapping problem, the self-avoiding walk, and the true-self-avoiding walk are briefly reviewed. New numerical results for diffusion on percolation clusters are also presented. 相似文献
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小波包变换是小波变换的推广,可视为普通小波函数的线性组合,具有良好的时频局部性和正交性,随着分解层数的增加,小波包分解能够在所有的频率范围聚焦。利用图像小波包变换的系数矩阵,能够构造出不同的人脸特征向量。针对人脸识别过程中的图像匹配问题,采用计算人脸特征向量方差的方法,并通过方差与权值的对应关系,转换出用于相似度计算的权值。基于理论推导得到的权值具有很好的稳定性,由这些权值计算出的方差相似度也具有较强的适应性,能够减弱由图像噪声、变形等干扰带来的影响。实验表明,该方法识别率高、实时性好。 相似文献
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基于Gabor小波纹理特征的目标识别新方法 总被引:5,自引:2,他引:5
给出了一种基于Gabor小波纹理特征的目标识别新方法.主要是利用Gabor小波设计了一种多通道小波滤波器。对图像目标直接进行小波变换,用Gabor小波变换系数的模的平均值和其标准方差来表示抽取的图像目标的特征,把获得的小波特征归一化后输入到改进的BP神经网络分类器进行分类识别.最后。进行了一系列的仿真实验,结果表明,这种特征提取方法能有效提取图像目标纹理特征,并且对噪音和形状的变化具有鲁棒性.在应用于目标识别时,神经网络的训练时间减少到lOmin,识别率达到94%. 相似文献
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提出了一种方便、科学有效的利用气体吸附法测定二氧化硅干凝胶等多孔材料分形维数(表面分形维数和孔分布分形维数)的方法,不需要进行一系列的吸附/脱附实验,只需要利用单一气体的一次吸附/脱附实验得出的样品孔分布、比表面数据,与不同的标尺进行关联,即可同时获得表面分形维数和孔分布分形维数.通过误差分析和校正,保证了结果的可靠性.用上述方法测定了二氧化硅干凝胶的分形维数,以FHH法和SAXS法对所得结果进行了比较和验证,并对吸附/脱附过程所得结果的差异进行了初步分析.
关键词:
分形维数
气体吸附
二氧化硅
干凝胶 相似文献