1 西安电子科技大学 物理与光电工程学院，陕西 西安 710071
2 西安电子科技大学 西安市计算成像重点实验室，陕西 西安 710071
3 西安电子科技大学 前沿交叉研究院，陕西 西安 710071
散射是光学成像中普遍存在的现象，成像路径中存在的烟雾、水体、生物组织等散射介质导致光束发生随机散射效应，使得像面处目标信息以杂乱无章的散斑形式存在，如何应对散射介质对成像的限制是当前光学成像领域的研究热点。全息技术能够记录和重建物体全部信息，是获取和解译光场信息的有力工具之一。近年来，传统全息以及相关全息理论被推广应用至散射成像领域，取得了一系列突破性成果，文中主要介绍与归纳了散射成像领域中应用全息技术的理论原理、发展历史及最新进展，并展望其发展前景。
散射成像 计算成像 相位共轭全息 合成波长全息 相关全息 scattering imaging computational imaging phase conjugate holography synthetic wavelength holography correlation holography 红外与激光工程
2022, 51(8): 20220307
1 Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
2 Department of Mining Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
3 College of Information Science and Engineering, Fujian Provincial Key Laboratory of Light Propagation and Transformation, Huaqiao University, Xiamen, Fujian 361021, China
Correlation holography uses incoherent light to reconstruct holograms. This technique reconstructs objects as distributions of two-point coherence function rather than using optical fields, as in conventional holography. The basic principle of correlation holography is derived from the van Cittert--Zernike theorem and relies on the similarity between the optical field and the coherence functions. Experimental implementation of the correlation holography techniques requires a field or intensity interferometer, and fringe analysis and cross-covariance measurement in these interferometers require a conventional camera with array detectors. With the availability of digitally controlled diffractive elements, it is possible to replace the incoherent light source, such as a rotating ground glass, with a digital source loaded with the random patterns in sequence. Such strategies ease the burden on the detector and allow for correlation holography with a single-pixel detector (SPD) to be used. This review paper discusses a close connection between digital holography and correlation holography. The principles of correlation holography with the SPD are reviewed in detail, and the advantages of using digital sources to mimic incoherent illumination in the correlation holography are examined in the context of three-dimensional and complex field imaging.
imaging systems correlation holography single-pixel detector digital holography coherence optics phase recovery 激光与光电子学进展
2021, 58(10): 1011011
华侨大学信息科学与工程学院, 福建省光传输与变换重点实验室, 福建 厦门 361021
由于随机散射效应,相干光束经过强散射介质后,出射光场变成光强呈无序分布的散斑场,因此无法直接从出射场获取入射光的信息。然而,在随机散射过程中,出射散斑场仍然携带着入射光场信息。从散斑场中获取原始信息以实现物体的重建是一个备受关注的研究课题。研究人员针对该问题提出了包括散斑相关、传输矩阵、波前调控及时间反演与相位共轭等技术。着重介绍了基于相关全息原理的散射成像技术,主要包括其原理、发展历史以及最新的研究进展,并对该技术的未来发展趋势进行了展望。
成像系统 散射成像 相关全息 散射介质 散斑场 激光与光电子学进展
2021, 58(2): 0200001
Author Affiliations
Abstract
1 Optical Sciences Centre and ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), School of Science, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
2 Melbourne Centre for Nanofabrication, ANFF, Clayton, VIC 3168, Australia
3 Tokyo Tech World Research Hub Initiative (WRHI), School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
Fresnel incoherent correlation holography (FINCH) is a well-established incoherent imaging technique. In FINCH, three self-interference holograms are recorded with calculated phase differences between the two interfering, differently modulated object waves and projected into a complex hologram. The object is reconstructed without the twin image and bias terms by a numerical Fresnel back propagation of the complex hologram. A modified approach to implement FINCH by a single camera shot by pre-calibrating the system involving recording of the point spread function library and reconstruction by a non-linear cross correlation has been introduced recently. The expression of the imaging characteristics from the modulation functions in original FINCH and the modified approach by pre-calibration in spatial and polarization multiplexing schemes are reviewed. The study reveals that a reconstructing function completely independent of the function of the phase mask is required for the faithful expression of the characteristics of the modulating function in image reconstruction. In the polarization multiplexing method by non-linear cross correlation, a partial expression was observed, while in the spatial multiplexing method by non-linear cross correlation, the imaging characteristics converged towards a uniform behavior.
digital holographic imaging Fresnel incoherent correlation holography holographic techniques imaging systems incoherent holography and speckle noise Chinese Optics Letters
2021, 19(2): 020501
郑州大学 物理工程学院, 河南 郑州 450001
菲涅耳非相干相关全息术(Fresnel Incoherent Correlation Holography, FINCH)属于同轴全息系统, 需要通过相移技术去除零级像和共轭像。通过对FINCH系统记录及再现过程的理论分析, 根据系统点扩散函数推导出了n步相移数学计算公式, 模拟仿真了相移步数n对FINCH系统成像质量的影响, 并搭建了非相干光反射式数字全息记录系统, 对模拟结果进行了实验验证。模拟仿真及实验结果表明: 通过增加相移步数不能显著提高再现像质量; 二步相移能够提高记录速度, 通过去除原始图像和小波分解的方法可以抑制零级像, 提高再现像质量; 通过对三步相移每个相移全息图拍摄多次求平均值后得到的再现像与拍摄一次得到的再现像对比发现, 随着拍摄次数的增加, 得到的再现像质量越来越好, 背景噪声大大减弱, 再现像强度越来越大, 为FINCH系统再现像质量的改善提供了新的思路和新的实验基础。
全息术 菲涅耳非相干相关全息术 相移技术 小波分解 holography Fresnel incoherent correlation holography phase-shifting technology wavelet decomposition 红外与激光工程
2019, 48(8): 0825001
基于菲涅耳非相干相关全息光路的望远系统, 可以在较远距离下, 得到目标物体的数字全息图。基于菲涅耳衍射理论, 计算了成像过程的点扩展函数(PSF), 理论上分析了菲涅耳非相干数字全息望远系统的成像原理、系统的横向放大率以及再现过程中的重建距离; 搭建了基于菲涅耳非相干相关同轴光路的数字全息望远系统, 在白光照明的条件下, 利用探测器(CCD)记录物体的全息图, 使用相移法消除了同轴光路下的零级像和共轭像, 通过角谱算法得到清晰的重建像。孔径光阑的引入, 解决了照明不均匀的问题,提高了成像质量。从实验上验证了系统的分辨率、景深以及三维成像特性。结果表明, 当望远系统角放大率为2.0倍、望远距离为900 mm时, 分辨率可达到16.00 lp/mm。
全息 非相干同轴数字全息 望远系统 菲涅耳非相干相关全息 激光与光电子学进展
2017, 54(12): 120902
