共查询到20条相似文献,搜索用时 31 毫秒
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一种改进的红外图像归一化互相关匹配算法 总被引:3,自引:2,他引:1
分析了传统归一化互相关算法在红外空中目标匹配定位时失效的原因,提出一种改进的红外图像归一化互相关匹配算法.该方法将模板和匹配区域之间的纹理相关计算看作一个最优化问题,寻求使图像纹理相关匹配鲁棒性最好的相关基准值,用图像的相关基准函数替代传统方法中的区域均值部分,构造了一种适用于的红外目标匹配的归一化相关算法.实验结果表明,该相关匹配算法对模板中背景部分的变化和非均匀性亮度变化有良好的抗干扰能力,较好地解决了恶劣环境下红外对空目标跟踪中匹配定位出错的问题. 相似文献
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快速啁啾算法引入两次快速傅里叶变换(FFT)及一个解析高斯核,计算复杂度低于卷积算法.通过对啁啾算法实现过程进行的改进,避免了该算法在实现过程中存在的一些问题,比如输出窗口小、信号丢失、计算复杂度稍大等缺点. 把算法用于简单的可求得解析解的系统并与之做比较. 对高斯函数,最大误差通常在10-15数量级,而对矩形函数,由于受FFT算法计算精度的影响,误差在10-3数量级,但这并不影响算法的性能. 最后把算法用于一种典型的标量衍射系统及分数傅里叶变换的计算,获得了很好的结果.
关键词:
快速啁啾算法
啁啾Z变换
菲涅耳变换
分数傅里叶变换 相似文献
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弹光调制傅里叶变换光谱仪(PEM-FTS)的调制光程差是高速、非线性变化,每秒可产生上万张干涉图。为了实现高速等时间采样干涉信号的快速光谱反演,对大光程差弹光调制干涉信号的特性、加速非均匀快速傅里叶变换算法(NUFFT)进行研究。加速非均匀快速傅里叶变换算法是基于卷积核函数插值的快速傅里叶变换算法,此算法的核函数类型、参数τ、延伸影响因子q、过采样率μ等参数的选择对算法准确度以及复杂度有影响。在分析这些参数对算法影响的基础上,在μ=2,q=10,τ=1×10-6时,将加速的NUFFT算法应用于弹光调制傅里叶变换光谱仪中,重建了632.8 nm的激光和氙灯光谱,复原的632.8 nm激光光谱的频率偏差小于0.013 52,插值时间小于0.267 s。实验表明加速的NUFFT算法有较快的运行速度和小的频率偏差,能快速准确地重建大光程差PEM-FTS的光谱。 相似文献
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Schaaf Peter Müller Alexander Carpene Ettore Kahle Michael 《Hyperfine Interactions》2002,144(1-4):129-139
Hyperfine Interactions - Thin films are playing a more and more important role for technological applications and there are many aspects of materials surface processing and thin film production,... 相似文献
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We review some experimental results which cannot be understood within the usual concepts of dissipative collisions. We present a dynamical model in which fast fission phenomenon appears in a natural way if certain conditions are fulfilled. Two kinds of fast fission are described, according to the size of the system. An extended notion of the so called fusion process is proposed and calculations of fusion cross sections are compared with experimental data. The fluctuations associated with the collective variables which are involved during fast fission and compound nucleus fission are treated within the framework of the linear response theory. The study of mass distributions supports the existence of fast fission with medium systems as an intermediate mechanism between the deep inelastic collisions and the compound nucleus formation. 相似文献
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We consider proton decay in the testable flipped SU(5)×UX(1) models with TeV-scale vector-like particles which can be realized in free fermionic string constructions and F-theory model building. We significantly improve upon the determination of light threshold effects from prior studies, and perform a fresh calculation of the second loop for the process p→e+π0 from the heavy gauge boson exchange. The cumulative result is comparatively fast proton decay, with a majority of the most plausible parameter space within reach of the future Hyper-Kamiokande and DUSEL experiments. Because the TeV-scale vector-like particles can be produced at the LHC, we predict a strong correlation between the most exciting particle physics experiments of the coming decade. 相似文献
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Fast deflagration-to-detonation transition 总被引:1,自引:0,他引:1
S. M. Frolov 《Russian Journal of Physical Chemistry B, Focus on Physics》2008,2(3):442-455
Studies of fast deflagration-to-detonation transition in gas and drop air-fuel explosive mixtures are reviewed. Fast deflagration-to-detonation transition is understood as the appearance of detonation at which a turbulent flame is sped up to a much lower velocity than that required for the classic deflagration-to-detonation transition in a straight tube with smooth or rough walls. The main goal of studies was to determine conditions under which fast deflagration-to-detonation transition was possible in weakly sensitive explosive mixtures at very low ignition energies. Examples of fast deflagration-to-detonation transitions checked experimentally and by multidimensional numerical calculations are given, including deflagration-to-detonation transitions (1) in a tube segment with regular obstacles of a special shape, (2) in tube coils, and (3) in tubes with U-shaped bends. In all cases, fast deflagration-to-detonation transition occurs because of the formation of distributed ignition zones in reflections of a running shock wave formed by an accelerated flame. The use of various combinations of reflecting elements can induce fast deflagration-to-detonation transition in an air mixture of aviation kerosene at ignition energies at a level of 5 J. 相似文献
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Mathematical optimization methods based on the topological sensitivity analysis have been used to develop innovative ultrasonic imaging methods. With a single illumination of the medium, they have proved experimentally to yield a lateral resolution comparable to classical multiple-illumination techniques. As these methods are based on the numerical simulations of two wave fields, they require extensive computation. A time-domain finite-difference scheme is usually used for that purpose. This paper presents the development of an experimental imaging method based on the topological sensitivity. The numerical cost is reduced by replacing the numerical simulations by simple mathematical operations between the radiation patterns of the array’s transducers and the frequency-domain signals to be emitted. These radiation patterns are preliminary computed once and for all. They were obtained with a finite element model for the anisotropic elastodynamic case and with semi-analytical integrations for the acoustic case. Experimental results are presented for a composite material sample and for a prefractal network immersed in water. A lateral resolution below 2.5 times the wavelength is obtained with a single plane wave illumination. The method is also applied with multiple illuminations, so that objects hidden in complex media can be investigated. 相似文献
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《Nuclear Physics A》1988,477(2):277-317
At a bombarding energy of 14.7 MeV/u the charge, mass and angular distributions have been measured as a function of energy loss for reaction products induced by 98Mo and 92Mo projectiles on targets of 98Mo, 147Sm, 154Sm and 92Mo, 154Sm, 238U, respectively. An analysis of the product distributions shows the presence of a non-equilibrium sharing of the excitation energy, an exponential growth of the charge and mass variances, a complete equilibration and a large yield of non-binary complex fragments. Monte Carlo simulations are found to be an indispensable tool of the analysis. 相似文献
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