共查询到19条相似文献,搜索用时 984 毫秒
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利用描述光波傍轴传输的光学分数傅里叶变换基本关系式,对单透镜系统进行分析,结果表明,单透镜系统可实现任意阶分数傅里叶变换,Lohmann第一类光学分数傅里叶变换装置是其特例,单透镜成像过程是进行阶次为π的分数傅里叶变换,进一步表明光学分数傅里叶变换的物理实质是光波的菲涅耳衍射。 相似文献
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分数傅里叶变换的无透镜光学实现 总被引:6,自引:0,他引:6
利用球面波照射物体的自由空间非涅耳衍射,完成任意级次分数傅里叶变换的无透镜光学实现,给出了不同条件下远透镜模式基本参量的选择法则及其分类傅里叶变换的数学表达,计算机模拟实验证明了结论的可靠与可行。 相似文献
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提出两种分数傅里叶变换数值计算新方法。本文用分数傅里叶变换描述信息在光学系统中的传输过程 ,分别基于分数傅里叶变换与菲涅尔变换之间联系和基于基本光学单元 (薄透镜及其组合 )实现分数傅里叶变换。该算法与光传输物理过程有着直观的联系 ,计算时光学系统的焦距、距离等参数可调。避免了传统算法中“变换核”等复杂计算 ,便于计算复杂光路和缩短计算时间。以三种飞机 (及字符 )光学模式识别实验为例 ,给出了空域 -频域变换混合光路的计算流程与结果 相似文献
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提出变形分数傅里叶变换双随机相位编码技术。详细阐述了编码与解码的光学原理,由于变形分数傅里叶变换比分数傅里叶变换多两个分数傅里叶变换阶次,所以,变形分数傅里叶变换双随机相位编码技术比分数傅里叶变换双随机相位编码技术增加了两重密钥,进一步提高了系统的保密性能。并进行了计算机模拟验证,结果证明该原理是正确的。 相似文献
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分数傅里叶变换全息图及其再现像的解析性 总被引:3,自引:0,他引:3
将分数傅里叶变换用于全息图制作,针对各种记录方式,全面研究了分数傅里叶变换全息图无透镜再现像的共轭关系和放大率关系,确切完整地给出了分数傅里叶全息术傍轴几何光学理论的数学表达和物理解释。计算机模拟实验证明了结论的可靠与可行。 相似文献
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Minsik Park Byung Gyu Chae Hyun‐Eui Kim Joonku Hahn Hwi Kim Cheong Hee Park Kyungae Moon Jinwoong Kim 《ETRI Journal》2014,36(2):232-241
A holographic display system with a 22‐inch LCD panel is developed to provide a wide viewing angle and large holographic 3D image. It is realized by steering a narrow viewing window resulting from a very large pixel pitch compared to the wave length of the laser light. Point light sources and a lens array make it possible to arbitrarily control the position of the viewing window for a moving observer. The holographic display provides both eyes of the observer with a holographic 3D image using two vertically placed LCD panels and a beam splitter to support the holographic stereogram. 相似文献
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虚拟透镜成像技术是一种可以兼顾远、中、近不同距离的成像新技术,但该技术是在被动成像的基础上发展起来的,适用于被动成像、半主动成像以及常规相控阵成像。在主动全息成像以及合成孔径成像系统中,由于天线单元依次工作并收发信号,目标回波信号具有不同的传播路径和相位延迟特性,因而不能直接采用虚拟透镜成像技术。文中对虚拟透镜成像技术进行扩展,针对主动全息成像和合成孔径成像的特点,引入了阵列属性参数,将其与信号传播路径和相位延迟特性进行关联,建立了一种多体制兼容的成像快速算法统一架构,并对相位加权算法进行了优化。所提出的新算法适用范围更广泛,且相位加权算法简洁易实现。最后进行了成像验证,实验及仿真结果证实了新算法的有效性。 相似文献
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针对“低慢小”目标光学成像识别能力差、复杂背景下信噪比低等问题,设计了一款低空高空间分辨率激光雷达光学系统。发射光学系统扫描器件采用MEMS反射镜,设计了专用扩束光学系统保证不同扫描角度发射激光的光束质量;接收光学系统采用物镜、数字微反射镜器件结合偏振器件,可同时实现激光回波接收与可见光成像,相较于采用单点探测器接收的激光接收系统,具有背景噪声低的优势。给出了光学系统的性能参数,利用光学设计软件设计了光学系统,该系统空间分辨率为0.5 mrad/pixel,扫描点阵列规模为200×200。模拟结果表明设计方法可行,计算其在大气中的探测距离可达到1000 m,背景噪声相较于单点探测器接收系统可降低约22162倍。 相似文献
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S. E. Bankov M. D. Duplenkova E. V. Frolova 《Journal of Communications Technology and Electronics》2014,59(10):1010-1032
A millimeter-band planar lens designed on the basis of an inhomogeneous medium with forced refraction, which is formed by a periodic grating of metal strips placed on the surfaces of a dielectric plate, is considered. The possibility of application of this lens as the basis for the design of a multibeam receiving antenna for a radio imaging system is analyzed. The structure of an antenna consisting of a planar lens and a multichannel feed is proposed. The results of the design of a planar lens based on an inhomogeneous medium with forced refraction are presented. A multichannel feed in the form of an array of E-plane horns is analyzed and the results of simulation of this feed with the help of an approximate technique and numerical solution of an electromagnetic problem are given. The design of the multibeam antenna and its experimental characteristics are presented. The possibility of computer correction of radiation patterns of the multibeam antenna is considered. 相似文献
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A unified framework for the fractional Fourier transform 总被引:8,自引:0,他引:8
Cariolaro G. Erseghe T. Kraniauskas P. Laurenti N. 《Signal Processing, IEEE Transactions on》1998,46(12):3206-3219
The paper investigates the possibility for giving a general definition of the fractional Fourier transform (FRT) for all signal classes [one-dimensional (1-D) and multidimensional, continuous and discrete, periodic and aperiodic]. Since the definition is based on the eigenfunctions of the ordinary Fourier transform (FT), the preliminary conditions is that the signal domain/periodicity be the same as the FT domain/periodicity. Within these classes, a general FRT definition is formulated, and the FRT properties are established. In addition, the multiplicity (which is intrinsic in a fractional operator) is clearly developed. The general definition is checked in the case in which the FRT is presently available and, moreover, to establish the FRT in new classes of signals 相似文献
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研究了如何利用普通网卡完成两台计算机之间的激光数字通信,介绍了光发射机、接
收机的设计考虑、基本原理和具体构成。并对系统的具体应用进行分析和讨论。 相似文献