共查询到18条相似文献,搜索用时 171 毫秒
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相移相位测量的全息再现算法及测量误差分析 总被引:2,自引:2,他引:0
用全息原理和方法研究相移相位测量,得到了N步整周期相移再现物光波复振幅同步叠加函数(N步相移函数),同时提出一种新的相移相位测量误差分析和最大误差估计方法。N步相移干涉图是以理想平行光为参考光的无衍射同轴全息图,将其与对应的相移参考光相乘后求和得到N步相移函数;在理想情况下,这是一种复振幅分离、测量和物光波复振幅函数同步叠加方法,存在误差时计算出的相位是最小二乘方法的最佳期望结果。利用N步相移函数得到的N 1步相移函数,说明非理想N步相移函数是理想N步相移函数与误差函数之和,可以把相位型误差转化为与振幅和强度相对误差同等的误差来对待,降低了相位测量中误差估计的难度,给出了N步相移算法最大误差的估计方法和公式。 相似文献
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提出了一种基于两步广义相移干涉术的波前再现技术以及基于衍射场统计特性的未知相移值提取算法,并且进行了光学实验验证.该方法中可仅利用两幅干涉图及一次不需精确预设的未知相移,参照物光光强和参考光光强,即可通过计算提取真实的相移量,进而恢复出物波波前复振幅,而无需借助傅里叶谱分析或数字滤波等操作.在光学实验中,对借助于空间光调制器(SLM)的间接输入和三维漫反射物体直接输入两种情况进行了详细地研究,得到的光学实验结果验证了所提方案的有效性和可行性.
关键词:
信息光学
相移干涉术
波前再现
数字图像处理 相似文献
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提出了一种双Lloyd镜数字全息显微测量技术.其基本思想是将Lloyd镜的共光束自干涉特性与双波长光学相位解包裹方法相结合,使用两个Lloyd镜调节参考光与物光夹角以形成共光束自干涉,从而获得一张双波长复合全息图,再通过角谱法再现得到每个波长对应的包裹相位,利用两波长的相位差求得解包裹后的相位图和三维高度分布图.采用532和632 nm两波长记录全息图,通过数值再现重构被测物体的振幅和相位信息.与标定值相比,实验值的误差小于5%,证明了该方法的有效性. 相似文献
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为实现对相位物体的无损检测和成像,克服数字同轴全息相位物体成像技术在消除零级像和孪生像的干扰时存在的系列问题,提出一种基于Stokes参量的新的数字同轴全息技术。该方法区别于传统的利用干涉光场来记录原始像项的数字全息方法,通过测量物参光合成光束的Stokes参量来分别得到这两束光的振幅和相位差,从而准确、唯一地获得原始像项;再利用数字再现即可重构物光的振幅和相位信息。实验中对弱吸收的相位样品进行了测量,得到样品清晰的振幅和相位分布。结果表明,采用该方法对相位物体进行数字全息再现,可以克服传统同轴全息图中零级像和共轭像对相位物体信息的严重干扰,对于提取相位物体的振幅和相位信息是可行和有效的。 相似文献
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提出一种计算全息算法,将物光波进行共轭对称延拓,经快速傅里叶变换直接生成实函数,其中包含物光波的幅度和相位信息,可编码得到灰度全息图.利用此全息图可清晰地再现原物光波.通过共轭延拓生成计算全息图的方法与以往基于干涉的计算全息不同之处在于,这里并不需要模拟物光和参考光的干涉,计算效率很高.利用生成的全息图在数字再现和光电再现实验中均获得了良好的效果.理论推导和实验结果都验证了算法的有效性.
关键词:
计算全息
共轭对称
数字再现
光电再现 相似文献
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相移干涉术及广义相移数字全息干涉术 总被引:1,自引:0,他引:1
在基础光学框架内说明了传统的相移干涉术及近年来发展的广义相移数字全息干涉术的基本原理;前者要求特殊值等步长相移,而后者则可以采用任意未知相移值.着重介绍了广义相移干涉术中的物波恢复算法,以及基于衍射场统计特性的未知相移提取算法.从一个侧面沟通了基础光学与近代光学之间的关系. 相似文献
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基于现有的相位空间光调制器,提出并实现了计算机制相位彩虹全息近眼显示.指出带限条件下物光在全息面上相位分布的计算及高频闪耀光栅纵向色散的控制是实现相位彩虹全息的关键要素.在计算相位彩虹全息图时,首先利用带限条件下的角谱衍射算法获取全息面上物光的复振幅分布,并利用双向误差扩散算法将复振幅分布编码为相位分布.然后,对参考光对应的高频闪耀光栅的相位进行编码,得到计算机制相位彩虹全息图.最后,设计了包含白色点光源、准直透镜、空间光调制器、4f滤波系统及目镜的全息彩色近眼显示系统,并通过光学再现获得了相位彩虹全息近眼显示效果,证明了所提方法的有效性. 相似文献
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A wavefront reconstruction method by two-step generalized phase-shifting interferometry (GPSI) with blind phase shift extraction algorithm is verified by both the computer simulations and optical experiments. This method can retrieve complex object wave field by using two interferograms, the recorded object and reference wave intensities, and an unknown phase shift without additional processing. The simulations with irregular wavefronts have shown the effectiveness and high accuracy of this method for blind phase-shift extraction and wavefront reconstruction over a wide range of phase-shifts, while the optical experiments for both the direct and indirect objects have yielded satisfactory results with a higher resolution of reconstructed image than those reported recently. 相似文献
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叠栅条纹信号细分误差的一种动态补偿方法 总被引:2,自引:0,他引:2
缺乏有效的误差补偿方法足制约长光栅测最精度提高的关键原因之一.提出一种动态的误差补偿方法.可以消除由直流漂移、两路信号不等幅和非止交导致的细分误差.其原理是跟踪光栅信号在一个周期上的8个特征值点(正余弦信号的过零点及绝对值交点),从特征值点的幅度值中首先分解出正弦信号的直流漂移误差.对其进行补偿;然后继续跟踪补偿后的信号.从中义能分解出余弦信号的直流漂移误差.再补偿.再跟踪.又能依次分解出不等幅误差和非正交误差.最多只需要3个光栅信号周期,就能对三种误差依次实现补偿.分析了谐波对该方法的影响并提出r改进措施.实验证实了该方法的有效性. 相似文献
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Junwei Min Baoli Yao Peng Gao Baiheng Ma Shaohui Yan Fei Peng Juanjuan Zheng Tong Ye Romano Rupp 《Optik》2012,123(17):1525-1529
An on-axis polarization phase-shifting digital holographic microscope, based on a normal upright optical microscope, is constructed to quantitatively measure both the amplitude and phase distributions of specimen. The condenser lens and microscope objective employed in the object beam path enhance the illumination and magnification of the image, however, they induce additional phase aberration of the object wave. The physical formation of the phase aberration is theoretically analyzed, and a formula for the object wave front involving the phase aberration in the CCD plane is derived. The phase aberration can be eliminated in the reconstruction procedure by measuring a specimen-free hologram and then fitting the aberration phase with a least square ellipsoidal model to determine the parameters of the system. This phase aberration compensation procedure also reduces some of noises in the reconstructed phase of the specimen. The practicability of this method is demonstrated by a test experiment on microlenses. 相似文献
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A complex-amplitude-based phase unwrapping approach for digital holographic microscopy is proposed in this paper. A quality map is derived directly from the reconstructed complex amplitude distribution of object wave to evaluate noise influence and phase reliability in the wrapped phase image. Quality-guided phase unwrapping algorithm is then implemented with the quality map to retrieve continuous phase profile. Unwrapping errors caused by unreliable phase data are successfully suppressed. The effectiveness of this method is demonstrated with simulation and experimental results. 相似文献
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The bidirectional error diffusion(BERD) algorithm is free from random phase modulation that introduces speckle noise on the reconstructed images, compared with other computer-generated phase-only hologram(POH) approaches. During the POH generation process, the amplitudes of all pixels are traditionally set to one for diffusing the errors to their neighborhood of unprocessed pixels. In this paper, we reveal that the reconstruction quality depends on the uniform amplitude value for different object pattern. The pattern-adaptive BERD(PA-BERD) algorithm is proposed for high-quality holographic reconstruction. The optimized amplitude value can be acquired for each object pattern and each propagation distance.The PA-BERD-based POHs have shown higher reconstruction quality than traditional BERD-based POHs in simulations as well as optical experiments. 相似文献
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像面数字全息是数字全息技术中常用的测量和成像方式,它通常采用离散傅里叶变换和频率滤波的方法进行物光波的重建.本文讨论了这些算法对重建相位的影响.首先分析了频谱泄露对于相位误差的影响,结果表明当采样周期为整数时,重建相位误差很小,因此具有极高的相位重建精度;而当不满足整周期采样时,相位重建误差有了明显的增加.为了改善频谱泄露所引起的相位误差,采用Hanning函数对数字全息图进行了预处理,结果表明Hanning窗的加入能够有效地提高重建相位的准确程度. 相似文献
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标准球面透镜是斐索型干涉仪的核心器件,综述标准球面透镜的几何特性和误差。分析标准球面透镜在干涉照明光路和成像光路中的作用,重点介绍并实验验证了球面干涉成像的R-sinθ几何特性关系模型,给出了采用Q非球面实现非球面分裂的新型设计方法,以及2片式非球面标准球面透镜结构的实例,概述了针对小F数标准球面透镜球面干涉腔中的待测球面调整误差和移相空间非均匀性误差的研究成果,介绍了校正球面干涉腔中误差的波面差分算法,指出在近标准球面透镜焦点位置测量球面时的回程误差影响,从物像共轭关系角度解释了近焦点位置回程误差较大的原因,比对分析了标准球面透镜的透射波前与斜率对回程误差的影响。提出了在设计标准球面透镜时需注意的几何特性关系,以及使用标准球面透镜时易产生的误差和相应的抑制方法。 相似文献
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We present a digital holography microscopy technique based on a parallel-quadrature phase-shifting method. Two π/2 phase-shifted holograms are recorded simultaneously using polarization phase-shifting principle, slightly off-axis recording geometry, and two identical CCD sensors. The parallel phase-shifting is realized by combining circularly polarized object beam with a 45° degree polarized reference beam through a polarizing beam splitter. DC term is eliminated by subtracting the two holograms from each other and the object information is reconstructed after selecting the frequency spectrum of the real image. Both amplitude and phase object reconstruction results are presented. Simultaneous recording eliminates phase errors caused by mechanical vibrations and air turbulences. The slightly off-axis recording geometry with phase-shifting allows a much larger dimension of the spatial filter for reconstruction of the object information. This leads to better reconstruction capability than traditional off-axis holography. 相似文献