共查询到20条相似文献,搜索用时 15 毫秒
1.
FANHong-Yi JIANGNian-Quan 《理论物理通讯》2004,42(1):23-26
We show that for n-dimensional complex fractional Fourier transform the corresponding complex fractional Radon transform can also be derived, however, it is different from the direct product of two n-dimensional real fractional Radon transforms. The complex fractional Radon transform of two-mode Wigner operator is calculated. 相似文献
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FAN Hong-Yi JIANG Nian-Quan 《理论物理通讯》2004,42(7)
We show that for n-dimensional complex fractional Fourier transform the corresponding complex fractional Radon transform can also be derived, however, it is different from the direct product of two n-dimensional real fractional Radon transforms. The complex fractional Radon transform of two-mode Wigner operator is calculated. 相似文献
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分数傅立叶变换的进展与展望 总被引:2,自引:1,他引:2
在综合国内外有关文献的基础上,评述分数傅立叶变换在信息光学中的新进展。概述分数傅立叶变换的发展过程,并对其研究现状进行了简略总结,同时对其未来的发展作出展望。 相似文献
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黑白胶片光栅编码彩色摄影术 总被引:5,自引:1,他引:4
用空间光栅将彩色景物记录到一张黑白胶片上(这一过程称为将彩色景物编码,所得的黑白透明片称为编码片)并通过再现(称为解码)装置再现彩色景物的思想和技术可以追溯到1899年,已有近百年的历史,开始时,类似于电子学中用时间信号调制载波方法,用彩色图像来调制光栅,十多年后便出现第一个萧条时期,持续将近半个世纪,期间比较重要的成果是有三个光栅进行三次编码记录的方法,到本世纪六十年代,又兴旺了一段时间,其中最 相似文献
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This paper is a further work of the authors' paper published previously (Liao T H and Gao Q 2005 Chin. Phys. Lett. 22 2316). The amplitudes of fractional Fourier transform of Cantor sets are analysed from the viewpoint of multifractal by wavelet transform maxima method (WTMM). An integral operation is carried out before the application of WTMM, such that the function obtained can be considered as the perturbed devil staircase. Also, wavelets with large number of vanishing moments are used, which makes the complete singularity spectrum more accessible. The validity of multifractal formalism is guaranteed by restricting parameter q to a proper range, so that the phenomenon of multifractal phase transition can be explained reasonably. Particularly, the method of determining the range of parameter q in the above paper is developed to be more operational and rigorous. 相似文献
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从分数傅里叶变换(FRFT)的定义出发,理论分析了联合分数变换相关器(JFRTC)的分数相关特性.从所得JFRTC的数学表达式中可以看出,将FRFT应用到联合变换相关器(JTC)中得到的JFRTC具有与传统JTC不同的性质.对于传统JTC,一旦输入平面上参考图像与目标图像之间的距离给定,相关输出峰的位置即确定,而JFRTC的相关输出峰的位置则可以由分数级次p1和p2来自由调节,这个特性在实际模式识别中非常有用.另一方面,JFRTC的相关输出峰值在大多数情况下低于传统JTC的相关峰值,却是JFRTC的一大缺点.最后,从FRFT的比例性质出发,给出了FRFT谱畸变不变的实现条件,并由此预言了JFRTC畸变不变模式识别的功能. 相似文献
8.
HU Li-Yun FAN Hong-Yi 《理论物理通讯》2008,50(10):951-954
By establishing the relation between the optical scaled fractional Fourier transform (FFT) and quantum mechanical squeezing-rotating operator transform, we employ the bipartite entangled state representation of two-mode squeezing operator to extend the scaled FFT to more general cases, such as scaled complex FFT and entangled scaled FFT. The additiyity and eigenmodes are presented in quantum version. The relation between the scaled FFT and squeezing-rotating Wigner operator is studied. 相似文献
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针对常规傅里叶变换所不能解决的啁啾噪声滤除问题,利用Wigner分布函数分析分数傅里叶变换的空域和频域特性,提出在分数傅里叶变换域进行啁啾滤波的方法。并将该方法应用到图像处理中,对分数傅里叶变换滤除一维和二维图像的啁啾噪声进行了计算机仿真,获得了满意的效果,结果表明该方法在图像处理中的有效性。 相似文献
10.
透镜组合实现光学分数傅里叶变换 总被引:4,自引:0,他引:4
从光学系统脉冲响应函数理论的角度分析了秀镜组合实现光学分数傅里叶变换的结构及标准焦距的物理意义,推导了几种较普遍的实现光学分数傅里叶变换的结构,利用该结构可以方便地改变其标准焦距,这对设计由多级数傅里叶变换级联构成的空间变化滤波系统具有重要的指导意义。 相似文献
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FRTH(fractional Fourier transform hologram) is a new kind of hologram that differs from common Fresnel holograms and Fourier transform holograms. Due to the flexibility of zone plate. A method that uses the -1 order diffraction wave of zone plate as the object wave and the 0 order diffraction wave as the reference wave to record FRTH is presented. It provides a new simple way to record FRTH. In this paper, the theory of achieving FRT and recording FRTH using holographic zone plate is presented and experimental results are given. 相似文献
13.
1 Introduction FRT(FractionalFourierTransform )wasfirstlyintroducedbyNamiasin 1 980asamathematictoolinquantummechanics[1] .In1 993,MendlovicandOzaktasimplementedtheFRTatopticalfieldwhentheystudiedgradientindex (GRIN )fiber[2 ] andappliedthepuremathematicformulatio… 相似文献
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分析了联合广义分数傅里叶变换相关器相关峰的特性,得到通过改变广义分数傅里叶变换的系统参量可以提高广义分数相关峰性能的结论.进行了数值模拟和光学实验,并根据两者的结果对四个相关峰的性能指标相关峰强度最大值、峰能比、识别能力、信噪比进行了比较分析,说明只要适当控制系统参量,联合广义分数傅里叶变换相关器比联合分数傅里叶变换相关器具有更好的相关性能,有助于提高光学相关器识别的准确率. 相似文献
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为了提高图像加密的安全性, 提出了一种多参数加权类分数傅里叶变换。此类多参数加权类分数傅里叶变换是C.C.Shih提出的四项加权类分数傅里叶变换的一种扩展, 除了分数阶数, 还有四个在四项加权系数之中的自由参数, 称其为向量参数。同时给出此多参数加权类分数傅里叶变换的离散形式, 并把这种算法应用到光学图像加密中。此算法在应用一次二维分数傅里叶变换可以有十个密键:一类为阶数参数; 另一类为向量参数, 因此这种加密算法在增加了安全性的同时, 加密过程的复杂度降低。数值仿真验证了此算法的有效性和可靠性。 相似文献
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We deduce entangled fractional Fourier transformation (EFFT) for
the multipartite entangled state representation, which was newly
constructed with two mutually conjugate n-mode entangled states of
continuum variables in n-mode Fock space. We establish a formalism
of EFFT for quantum mechanical wave functions, which provides
us a convenient way to derive some wave functions. We find that
the eigenmode of EFFT is different from the usual Hermite Polynomials.
We also derive the EFFT of the n-mode squeezed state. 相似文献
19.
基于随机分数傅里叶变换的双图像加密算法 总被引:1,自引:2,他引:1
利用光学随机分数傅里叶变换设计了一种双图像加密算法,并给出了相应的光学实现.加密算法中,将两幅原始图像分别作为加密系统输入复函数的振幅和位相分布函数,利用随机分数傅里叶变换进行加密,所得复函数的振幅即为加密图像,而位相部分是变换的输出相位,随机位相作为加密算法的密码.在数值模拟中,二值文本图像和灰度图像分别被作为原始图像用于加密结果分析和加密安全测试,结果表明该加密算法具有很好的安全性. 相似文献