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《Journal of Modern Optics》2013,60(7):725-732
A computational method has been devised for optimizing holograms of high dynamic range. As an example the Fourier hologram of a slit is given and application to holographic correlation is shown. 相似文献
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《Journal of Modern Optics》2013,60(6):843-855
A method for coding many phase objects by means of a binary synthetic hologram is presented. The paper gives a vectorial analysis of the spectrum of multi-exposure synthetic holograms and the analysis of the storage capacity of the method. On the basis of theoretical considerations and experimental results, the errors caused by the overlapping of the first diffraction order reconstructed wavefront with beat frequencies are discussed. 相似文献
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在分析递归二元搜索算法合成计算全息图原理的基础上,计算机编程设计了递归二元搜索型计算全息图,并在实验上研究了计算全息图的恢复象。实验结果表明,递归二元搜索算法可合成任意波前分布的傅里叶变换计算全息图,并具有恢复象质量好,衍射效率高的特点。 相似文献
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Localization relations arise naturally in the formulation of multi-scale models. They facilitate statistical analysis of local phenomena that may contribute to failure related properties. The computational burden of dealing with such relations is high and recent work has focused on spectral methods to provide more efficient models. Issues with the inherent integrations in the framework have led to a tendency towards calibration-based approaches. In this paper a discrete Fourier transform framework is introduced, leading to an extremely efficient basis for the localization relations. Previous issues with the Green's function integrals are resolved, and the method is validated against finite element analysis. 相似文献
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基于傅里叶变换的正弦信号源波形失真评价方法 总被引:9,自引:1,他引:8
介绍了一种直接利用经典傅里叶变换技术评价正弦信号源波形总失真度的过程和方法。借助于周期的精确测量技术,实现基波参数的精确测量。用时域能量方式计算失真,其内涵全面,包括了谐波、杂波、噪声等全部影响,并对测量系统本身的影响进行了补偿。同时,对不同条件下的失真度测量误差进行了分析,用一组仿真数据的实验结果,验证了正确性及可行性。所述方法可用于正弦信号波形失真度的精确测量和计量校准,尤其适用于大失真度的测量。 相似文献
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Francois J. Resch Rudolf Abel 《International journal for numerical methods in engineering》1975,9(4):869-902
The present study is intended as a guide for those who wish to undertake spectral analyses using Discrete Fast Fourier Transforms. Points of particular difficulty in using Fourier Transforms are derived in some detail. Experimental results are offered to illustrate the mathematical derivations. Finally the case of a signal with discontinuities along the time-axis is discussed. 相似文献
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FFT谱连续细化分析的富里叶变换法 总被引:73,自引:14,他引:73
本文提出了利用富里叶变换对FFT谱的局部进行细化分析的方法。在细化频谱分析时,可以得到某个主要频率成份频率、幅值、相位的精确值,极大地提高频率分辨力,对瞬态及恒定采样长度信号的频率细化分析十分有效。 相似文献
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Guizar-Sicairos M Gutiérrez-Vega JC 《Journal of the Optical Society of America. A, Optics, image science, and vision》2004,21(9):1682-1688
We obtain a Fourier transform scaling relation to find analytically, numerically, or experimentally the spectrum of an arbitrary scaled two-dimensional Dirac delta curve from the spectrum of the nonscaled curve. An amplitude factor is derived and given explicitly in terms of the scaling factors and the angle of the forward tangent at each point of the curve about the positive x axis. With the scaling relation we determine the spectrum of an elliptic curve by a circular geometry instead of an elliptical one. The generalization to N-dimensional Dirac delta curves is also included. 相似文献
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用于沙体三维形态检测的二维傅立叶变换轮廓术 总被引:1,自引:0,他引:1
提出一种二维傅立叶变换轮廓术,对于在变换条纹图象中存在不连续条纹和类散斑结构噪声时,这种方法比传统的傅立叶变换轮廓术方法优越,能够正确地恢复物体三维面形,本文中给出这种方法的理论推导和沙体三维形态检测的实验结果。 相似文献
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提高Fourier变换轮廓术测量精度的新方法 总被引:14,自引:4,他引:14
在傅里叶变换轮廓术测量方法中,对离散的条想方设法进行DFT(离散傅里叶变换)运算,存在“栅栏效应”,离散频谱不能完全无误地代表原连续频谱分布,相当于在频域内发生了谱信息损失。为了减小由“栅栏效应”引入的位相误差,采用了对条纹进行空域数值加权和外插补零方法,从而提高FTP的测量精度。计算机模拟证实了所提方法的有效性。 相似文献
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We consider the dependences of the error of a discrete Fourier transform on the length of the realization of the considered signal. The introduction of a procedure of making a preliminary determination of the period makes it possible to consider signals in short samples and this significantly reduces the computing and apparatus costs. 相似文献
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M. Hegland W. W. Wheeler 《Applicable Algebra in Engineering, Communication and Computing》1997,8(2):143-163
Fast Fourier transform algorithms rely upon the choice of certain bijective mappings between the indices of the data arrays.
The two basic mappings used in the literature lead to Cooley–Tukey algorithms or to prime factor algorithms. But many other
bijections also lead to FFT algorithms, and a complete classification of these mappings is provided. One particular choice
leads to a new FFT algorithm that generalizes the prime factor algorithm. It has the advantage of reducing the floating point
operation count by reducing the number of trigonometric function evaluations.
A certain equivalence relation is defined on the set of bijections that lead to FFT algorithms, and its connection with isomorphism
classes of group extensions is studied. Under this equivalence relation every equivalence class contains bijections leading
to an FFT algorithm of the new type.
Received October 27, 1994; revised version January 25, 1996 相似文献