CG光学扫描全息术和FZP光学扫描全息术分辨率比较

本文通过计算机仿真对ＦＺＰ 光学扫描全息术和ＣＧ 光学扫描全息术的横向和纵向分辨率进行了比较。无论是ＦＺＰ 还是ＣＧ 光学扫描全息术,其系统的分辨率与它们的环数有关,当环数越多时,分辨率越高。对于同样大小的ＦＺＰ 和ＣＧ,ＣＧ 光学扫描全息系统的分辨率比ＦＺＰ 光学扫描全息系统的分辨率要好     

环形光栅光学扫描全息术的研究

为了充分利用光学扫描全息系统的分辨率,提出了用环形光栅扫描物体的光学扫描全是术。其优点是：可以用非相干光源记录扫描全息图,系统为单光路,从而可以提高系统的稳定性。阐明了环形光栅光学扫描全息术的基本原理,并给出了实验结果。     

光学扫描全息术研究进展

光学成像技术极大地拓展了人类的视觉极限,提高了人们观察和理解现实世界的能力。越多地获得目标的光学信息,对其的认识越充分。数字全息术是一种可以将样本的三维信息以二维全息图的形式编码记录下来的一种成像技术。通过获得由携带物体信息的物光波和参考光波叠加产生的干涉图案,可以以数字化的方式实现多种重建模态,例如图像恢复、相位成像和切片成像等。光学扫描全息术是一种独特的数字全息成像技术,通过主动式二维化扫描对三维物体进行成像,其完整的波前信息可以被单像素探测器记录,并基于光外差检测进行信号解调,从而恢复出复数全息图。对光学扫描全息术的最新进展进行介绍。首先,基于双光瞳成像系统,通过特殊的硬件和算法设计,提高光学成像系统的性能,如提高空间分辨率、缩短扫描时间。其次,基于计算成像原理,通过改进和优化全息像重建算法,实现高质量的图像恢复,主要涉及切片成像和三维成像等重建模态。第三,介绍光学扫描全息术的其他研究方向,并讨论该领域未来可能的发展方向。     

光学扫描全息术中的孪生像噪音及消除

阐述了光学扫描全息术的基本原理,分析了孪生像噪音的来源,提出了一种新的数字滤波方法.计算机仿真结果表明:孪生像噪音以振荡形式传播,降低了重构图像的信噪比,影响了重构图像的分辨率;用电子复用技术,即用复全息图函数代替实全息图函数的方法可以有效地消除孪生像噪音;采用单一通道对信号进行处理,即只用一个实全息图函数,通过数字滤波方法同样可以消除孪生像噪音,该方法简便、实用而有效.     

高斯光学型扫描全息系统的点扩散函数

根据激光束的空间分布为高斯型分布，文中推导了理想和实际光学扫描系统的点扩散函数，理想系统的点扩散函数为δ函数，实际系统的点扩散函数为高斯函数。     

复合扫描全息术及透过强散射介质三维成像研究

应用菲涅耳波带片光学扫描全息术原理,研究强散射介质中吸收体的三维成像.针对由成像物体强散射背景产生的背景噪音,提出复合扫描全息术成像方法.实验中应用这一方法,对嵌埋在浓度为1%,深度为1.7 cm的脂肪乳剂中的吸收体成像,得到了信噪比和对比度较好的再现像.在此基础上,对复合扫描全息成像系统的信噪比,对比度及分辨率等性能进行了深入的理论分析和实验测试.研究表明,与单一模式相比,复合扫描全息术在信噪比和对比度方面有较大改善,但分辨率还需进一步提高.     

基于菲涅耳波带板扫描全息术的光学层析成像

基于光学扫描全息术原理和编码孔径层析成像技术,提出了一种三维物体层析成像技术——菲涅耳波带板扫描全息术。该技术通过将物体的光强分布函数与菲涅耳波带板的光强分布函数进行卷积运算来得到物体的扫描全息图,通过相关解卷积的方法来进行扫描全息图的数字重建。依据该技术原理设计了实验系统,系统结构简单紧凑,具有三维物体层析成像功能。提出用数字高通滤波器来减少重建图像的背景噪声。计算机仿真及对实物的扫描记录和重建实验结果表明,该技术原理正确,用于三维物体层析成像是可行的,用数字高通滤波的方法提高重建图像的对比度是有效的。     

X射线全息术

本文介绍了Ｘ射线全息术的工作原理和进展状况，详细地论述了与Ｘ射线全息术有关的Ｘ射线光学、Ｘ射线光学元件和Ｘ射线源的特性，并讨论了Ｘ射线全息实验的要求和记录方式，最后着重探讨了包括记录过程和重现过程中影响Ｘ射线全息术分辨率的各种因素。     

振镜扫描光学多道谱仪

以平面光栅单色仪和光学扫描振镜为基础研制一套具有高时间分辨能力的光学多道分析系统,并利用计算机进行实时控制与数据采集。实验表明：本系统在保持谱分辨的同时,时间分辨率达到１０ｍｓ以内。     

全息术的发展和应用

本简介了光全息术的原理，并对半个世纪以来光全息术的发展及应用作了概述。     

Twin-image elimination in optical scanning holography

We propose a novel multiplexing technique to solve the twin image problem in optical scanning holography without the use of a spatial carrier, as commonly used in conventional off-axis holography. The technique involves simultaneously acquiring sine and cosine Fresnel zone-lens plate coded images by optical scanning. A complex addition of the two coded images will then be performed and decoded to give a twin-image rejection reconstruction. Computer simulations will be presented to demonstrate the validity of the idea.     

基于光学全息指纹锁的设计与仿真

本文提出了一种基于光学全息的“指纹锁”,将其放置在智能卡的IC芯片前面,用于对用户的个人识别号(PIN码)进行预先加密和认证,和智能卡原有的数字加密算法相结合,可进一步提高信息存储和提取的安全性.该指纹锁是以指纹图像和随机相位板为密钥,记录在光折变晶体材料内的一组角度复用加密全息图.这种光学加密全息图与传统的角度复用全息图不同,其参考光兼有指纹密钥的振幅调制和随机相位调制,具有私密性好、携带方便、安全性高等优点.     

Relationship between the fringe number of the scanning beam and the twin-image noise

A method of digital filtering for eliminating the twin-image noise of reconstructed images in optical scanning holography is proposed and demonstrated by the example of slit objects. The fringe number of the scanning beam in relation to the twin-image noise is investigated in detail. Some results of computer simulations are obtained. In the far field, the further object scanned by the scanning beam with fewer fringes has lower and flatter amplitude of the twin-image noise for reconstructed images. However, being independent of the fringe number the twin-image noise affects seriously on the reconstruction in the near field. So the twin-image noise should be considered in reconstruction in the near field.     

Variable tomographic scanning with wavelength scanning digital interference holography

We present a new method for variable tomographic scanning based on the wavelength scanning digital interference holography (WSDIH). A series of holograms are generated with a range of scanned wavelengths. The object field is reconstructed in a number of selected tilted planes from each hologram, and the numerical superposition of all the tilted object fields results in a variable tomographic scanning. The scanning direction can be arbitrary angles in 3D space but not limited in a 2D plane, thus the proposed algorithm offers more flexibility for acquiring and observing randomly orientated features of a specimen in a WSDIH system. Experiments are performed to demonstrate the effectiveness of the method.     

Spectral holography of pico- and nanosecond optical pulses

Recording and reconstruction of pico- and nanosecond pulses have been accomplished with spectral holography. The development of spectral holography in the nanosecond time-domain was achieved while using high-spectral-resolution equipment based on a Fabry-Perot etalon with a side entrance/exit. The recognition of the shaped nanosecond light pulses was also realized.     

新型高时间分辨的光扫描模块偏转特性

随着惯性约束聚变研究的深入发展,对高精密诊断设备的要求越来越高,基于半导体材料的光致折射率变化这一特性,对新型高时间分辨的全光扫描技术进行了深入研究。重点介绍了影响光扫描模块偏转特性的两大关键技术,即光扫描模块的设计以及泵浦光与信号光时间同步。通过分解实验开展验证性研究,结果表明：通过前期设计制作的光扫描模块可较好地应用于实验中,在一定范围内,泵浦光功率密度越大信号光的偏转也就越大。同时,时间同步对信号光的偏转程度影响也较大,即高时间同步关系也决定了光扫描装置的时间分辨率。     

Optical receiving solution for optical scanning lag effect of LADAR

Optical scanning plays a very important role in LADAR system for large field of view (FOV). But it introduces the optical scanning lag effect due to the optical scanning and the time delay between laser pulse transmitting and receiving. Optical scanning lag angle will make a part of received optical energy fall out of the optical sensitive area of detector, which will greatly degrade the detecting performance of LADAR in many cases. Optical scanning lag effect and optical scanning lag angle are firstly computational analyzed in detail in this paper. A novel optical receiving design approach is proposed, and the experimental result is given.     

Functional imaging in photorefractive tissue speckle holography

Cellular motion produces highly dynamic speckle in wide-field depth-gated holographic optical coherence imaging. The speckle provides cell scale information such as cell membrane and organelle motion, even though the spatial resolution of the optics is above the cell scale. The statistical properties of dynamic speckle can be used for functional imaging of motile activity at depth within tissue. In this paper we develop a motility metric using time autocorrelation to create a three-dimensional motility map of tissue. The effect of noise and the shimmering showerglass effect in functional optical coherence imaging are evaluated quantitatively, and we demonstrate that meaningful motility information can be extracted from functional imaging using dynamic speckle.     

共口径双通道红外扫描成像光学系统

对双波段红外扫描成像光学系统进行了研究,结合三次成像技术和100%冷光栏效率技术,设计了一个共口径双通道红外扫描成像光学系统。该系统包括前端共用的双反射系统、分束镜、准直镜组、扫描镜和成像镜组。光波经过双反射系统在主镜之后被分束镜分成中波红外通道（3 m～5 m）和长波红外通道（10 m～12 m）,经准直镜组及成像镜组会聚探测器上,实现中波红外系统与长波红外系统共口径同步成像。设计结果表明,长波红外系统传递函数在18 lp/mm处达到0.4以上,中波红外系统传递函数在18 lp/mm处达到0.78以上,满足实际应用的要求。