位相调制图像密度假彩色编码的处理方法

介绍了位相调制图像密度假彩色编码的原理及实验方法，并就实验过程中应注意的一些问题作出了较详细的说明     

利用随机位相编码技术对光学图像进行保密

本文介绍了一种利用随机位相编码技术对光学图像进行保密的方法，该方法是利用两个随机位相掩模将振幅识别的初始图像编码为复振幅稳定的白光噪声，使仅对光强敏感的探测器无法接收。保密图像再现所采用光学方法具有最大的光学效应。     

利用随机位相编码技术对光学图像进行保密

本文介绍了一种利用随机位相编码技术对光学图像进行保密的方法．该方法是利用两个随机位相掩模将振幅识别的初始图像编码为复振幅稳定的白光噪声,使仅对光强敏感的探测器无法接收．保密图像再现所采用光学方法具有最大的光学效应．     

用傅科刀口实现位相物体的假彩色编码

本文提出了用傅科刀口法实现位相物体的假彩色化，对方法进行了理论分析，并给出了实现结果。此法与以往的假彩色编码方法相比，结构简单，操作方便，效果良好。     

位相编码振幅调制联合变换相关器的设计

采用位相编码技术减小了经典联合变换相关器中的直流分量 ,及多目标输入时各目标图像之间的互相关项 ,并且同时消除了参考图像和各目标图像之间的共轭相关项。通过对联合功率谱进行振幅调制 ,缩小了相关峰的宽度 ,锐化了相关峰 ,增强了识别能力。最后给出了计算机模拟结果。     

利用液晶电视实现光学图像的实时边缘提取

通过对扭曲向列型液晶电视的光学调制特性研究,利用其位相调制模式下灰度图像与位相调制的映射关系和光学干涉效应,实现了实时光学图像边缘提取.该方法不仅实时处理效果好,而且系统紧凑、操作简单.     

调制边缝位相的全息三缝干涉仪

本文介绍了调制一条边缝光路位相的全息三缝干涉仪。其量程比调制中缝位相的三缝干涉仪扩大一倍,并能对大范围的连续光程变化进行测量。     

利用腔内位相调制改善固体激光器的光束质量

提出一种新的利用腔内位相调制的方法来改善激光器输出的光束质量。位相调制用铌酸锂 (LiNbO3 )电光晶体实现 ,所用激光器为连续氪灯抽运的Nd∶YAG激光器。实验结果表明 ,利用腔内位相调制的方法 ,可以有效地使多模激光变为具有均匀光强分布的近基模光束     

时空域位相调制型光学谐振腔的模式

提出一种含有时空位相调制元件的光学谐振腔 ,利用空间 -频率域的相干模式理论对这种谐振腔的模式作了分析和数值模拟。结果表明 ,对固定位相片 ,腔内光场是完全相干的 ,在一定参数下 ,在一镜面上可得到平顶光束 ;对随机微扰型位相片 ,输出模式是部分相干的 ,在合适参数下 ,也可得到平顶光束。     

可见光通信中的无载波位相调制技术

为了保证可见光通信(VLC)系统能够为智能终端提供高速率、低能耗的数据传输服务。该文基于脉冲位置调制(PPM)技术,提出了一种新型的无载波位相(CPP)调制技术,即通过运用正交滤波器提高了PPM的传输速率。而针对采用CPP调制在VLC系统中功率效率显著降低的问题,提出了全新的时变偏置有效地降低了系统的功耗。最后仿真结果表明,采用时变偏置的CPP系统同采用直流偏置相比,在获得相同BER性能且带宽受限的情况下可以节省2 dB的信噪比。而同时考虑信号时隙之间的相关性,时变偏置可以进一步提升约1.5 dB的BER性能。     

相位型图像实时可调假彩色编码

相位型图像经滤波后写入液晶光阀,用白光读出,可以实现相位型图像实时可调假彩色编码。采用液晶光阀的简化混合场效应模式,论述了这种编码方法的原理。给出了典型的假彩色编码结果。     

Electrooptic phase modulation in CdS optical waveguides

Thin polycrystalline films of CdS have been successfully adapted into a multilayer Configuration to form the basis of low-electrical-drive-power optical phase modulators. An experimental structure with a guide thickness of 1.4 μm, buffer thicknesses of 0.45 μm and an electrode area of 10 × 0.5 mm²requires 11.2 mW. MHz^-1drive power for a phase change of 1 rad.     

点光源照射下彩色图像随机相位编码的实现

为了实现对彩色图像的单随机相位编码,根据随机相位编码原理,提出采用单色点光源照射系统结合波长多路技术,实现了对组成彩色图像的三基色图像进行随机相位编码。理论分析和数值模拟显示,采用单色点光源照射系统,对彩色图像进行随机相位编码是可行的;同时由于系统装置的减少,有效地减少了由于随机相位掩膜所引起的相应光能损失和图像噪声。结果表明,这种方法在追求彩色还原度高的场合具有实用价值。     

An electric-field sensitive fiber with coaxial electrodes for optical phase modulation

It was shown that an electric-field sensitive optical fiber utilizing a radially poled piezoactive copolymer jacket is suitable for application as an all-fiber optical phase modulator. The jacket used was a copolymer of vinylidene fluoride and trifluoroethylene (P(VDF73/TrFE27)), 63-μm thickness, and was made radially piezoactive by corona discharge poling. The optical response of induced phase shift due to applied dc voltages was measured to be between0.80 times 10^{-5}and1.24 times 10^{-5}rad/(V/m) per meter of fiber. The performance of the jacketed fibers with coaxial electrodes as an optical phase modulator was tested over a wide frequency of range, from 20 Hz to 20 KHz.     

Piezoelectrically induced optical phase modulation of light insingle-mode fibers

Optical phase modulation induced in piezoelectric copolymer, vinylidene fluoride (73 mol.%)/trifluoroethylene (27 mol.%), coated single-mode fibers has been examined and analyzed from both experimental and theoretical aspects. High-sensitive phase modulation, which is more than four times as large as those of vinylidene fluoride/tetrafluoroethylene copolymer, is obtained over a flat response range from 10 kHz to 3 MHz. At frequencies below 7 kHz and higher than 6 MHz the optical responses are dominated by axial and radial resonances, respectively, of the fiber-jacket composite. The theoretical prediction on induced phase shifts at high frequencies is carried out based on radial vibration analysis and followed by the experimental results     

High-performance optical phase modulation using piezoelectricZnO-coated standard telecommunication fiber

Optical phase modulation in a standard telecommunication fiber coated with a piezoelectric ZnO jacket has been investigated both experimentally and theoretically. The frequency response of the modulator exhibits 18 peaks between 20 and 800 MHz, which correspond to radial resonances of the coated fiber composite. A theoretical model was developed to explain the experimental results. The model takes into account the geometry of the modulator, nonuniform strain distributions, and the structure of the ZnO film. The calculated positions of the resonances and cancellation of phase modulation at frequencies higher than 800 MHz agree well with the measured data. The analysis also demonstrates the capability of tuning the resonances positions by varying the thickness of the ZnO jacket or the metal electrodes     

相位调制在可见光与红外图像融合中的应用

根据实际应用中要求图像融合算法简单有效的要求,提出了相位调制的图像融合算法,首先对可见光图像和红外图像按照通信原理中的相位调制方法进行相位调制,然后通过逆变换得到融合图像,通过实验表明,该算法在图像视觉效果、包含的信息量以及细节信息上都取得很好的效果,融合效果优于小波变换等算法。     

Cascadability study for optical label swapping using synchronous phase modulation

We experimentally investigate the cascadability of optical label swapping using a synchronous phase modulation technique without wavelength conversion in a recirculating loop to emulate multihop networks. We find that the power penalties for both label and payload are below 1 dB at 10/sup -7/ bit-error rate after five hops. We also show that a system penalty can be maintained below 1 dB for an accumulated timing mismatch of 20% of bit period using synchronous phase modulation-based optical label swapping. The results show the potential to save up to 80% of wavelength converters in optical packet switched networks applications.     

Phase modulation efficiency and transmission loss of silicon optical phase shifters

This paper focuses on understanding the phase efficiency and optical loss of MOS-capacitor-based silicon waveguide phase shifters. A total of nine designs have been fabricated using poly-silicon and characterized at wavelengths around 1.55 /spl mu/m. Detailed comparison of design parameters shows that scaling down the waveguide dimensions, placing the capacitor gate oxide near the center of the optical mode, and reducing the oxide thickness significantly enhance phase modulation efficiency. Our best design to date demonstrates a /spl pi/-radian phase shift with 0.8-cm device length and 3-V drive. This phase shifter has a transmission loss of 15 dB, the primary source of which is the poly-silicon regions inside the device. An improved material can reduce loss to as little as 4 dB.     

Characterization of an optical frequency-shift-keying transmitter based on carrier-suppressed phase modulation

We experimentally characterize an optical frequency-shift-keying transmitter based on optical carrier-suppressed phase modulation. Only one laser source is needed to generate an optical FSK signal. The demonstration of 10-Gb/s FSK signal generation and 50-km transmission verified the improved performance of the proposed transmitter, compared with the previous two-laser schemes. To further reduce the complexity of the transmitter, the phase modulator is omitted and a single MZM modulator is used for both optical carrier-suppression (OCS) and phase modulation. This simplified structure is verified by simulation, implying the feasibility that a FSK transmitter can be constructed with only one laser source and one modulator.