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Resolution enhancement of optical scanning holography with a spiral modulated point spread function

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Photonics Research 2016年第1期4卷 1-6页

作者： Ni Chen Zhenbo Ren Haiyan Ou Edmund y.lam Department of Electrical and Electronic Engineering The University of Hong Kong Institute of Applied Physics University of Electronic Science and Technology of China

In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolution of the hologram reconstruction is affected by the point spread function(PSF) of the optical system. In this paper, we modulate the PSF by a spiral phase plate, which significantly enhances the lateral and depth resolution. We explain the theory for such resolution enhancement and show simulation results to verify the efficacy of the approach.

关键词： PSF Resolution enhancement of optical scanning holography with a spiral modulated point spread function

Fast and robust phase retrieval for masked coherent diffractive imaging

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Photonics Research 2022年第3期10卷 758-768页

作者： Li Song Edmund y.lam Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong KongChina

Conventional phase retrieval algorithms for coherent diffractive imaging(CDI)require many iterations to deliver reasonable results,even using a known mask as a strong constraint in the imaging setup,an approach known as masked *** paper proposes a fast and robust phase retrieval method for masked CDI based on the alternating direction method of multipliers(ADMM).We propose a plug-and-play ADMM to incorporate the prior knowledge of the mask,but note that commonly used denoisers are not suitable as regularizers for complex-valued latent images ***,we develop a regularizer based on the structure tensor and Harris corner *** with conventional phase retrieval methods,our technique can achieve comparable reconstruction results with less time for the masked ***,validation experiments on real in situ CDI data for both intensity and phase objects show that our approach is more than 100 times faster than the baseline method to reconstruct one complex-valued image,making it possible to be used in challenging situations,such as imaging dynamic ***,phase retrieval results for single diffraction patterns show the robustness of the proposed ADMM.

关键词： coherent phase retrieval

Unsupervised learning on scientific ocean drilling datasets from the South China Sea

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Frontiers of Earth Science 2019年第1期13卷 180-190页

作者： Kevin C.TSE Hon-Chim CHIU Man-yin TSANG yiliang LI Edmund y.lam Department of Earth Sciences The University of Hong KongPokfulamHong KongChina Department of Geography and Centre for Geo-computation Studies Hong Kong Baptist UniversityKowloon TongHong KongChina Department of Earth Sciences University of TorontoTorontoON M5S 2M8Canada Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong KongChina

Unsupervised learning methods were applied to explore data patterns in multivariate geophysical datasets collected from ocean floor sediment core samples coming from scientific ocean drilling in the South China *** to studies on similar datasets,but using supervised learning methods which are designed to make predictions based on sample training data,unsupervised learning methods require no a priori information and focus only on the input *** this study,popular unsupervised learning methods including K-means,self-organizing maps,hierarchical clustering and random forest were coupled with different distance metrics to form exploratory data *** resulting data clusters were externally validated with lithologic units and geologic time scales assigned to the datasets by conventional methods. Compact and connected data clusters displayed varying degrees of correspondence with existing classification by lithologic units and geologic time scales.K-means and self-organizing maps were observed to perform better with lithologic units while random forest corresponded best with geologic time *** study sets a pioneering example of how unsupervised machine learning methods can be used as an automatic processing tool for the increasingly high volume of scientific ocean drilling data.

关键词： machine learning unsupervised learning ODP IODP clustering

On the use of deep learning for phase recovery

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Light(Science & Applications) 2024年第2期13卷 190-235页

作者： Kaiqiang Wang Li Song Chutian Wang Zhenbo Ren Guangyuan Zhao Jiazhen Dou Jianglei Di George Barbastathis Renjie Zhou Jianlin Zhao Edmund y.lam Department of Electrical and Electronic Engineering The University of Hong KongHong Kong SARChina School of Physical Science and Technology Northwestern Polytechnical UniversityXi’anChina Department of Biomedical Engineering The Chinese University of Hong KongHong Kong SARChina School of Information Engineering Guangdong University of TechnologyGuangzhouChina Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMAUSA

Phase recovery(PR)refers to calculating the phase of the light field from its intensity *** exemplified from quantitative phase imaging and coherent diffraction imaging to adaptive optics,PR is essential for reconstructing the refractive index distribution or topography of an object and correcting the aberration of an imaging *** recent years,deep learning(DL),often implemented through deep neural networks,has provided unprecedented support for computational imaging,leading to more efficient solutions for various PR *** this review,we first briefly introduce conventional methods for ***,we review how DL provides support for PR from the following three stages,namely,pre-processing,in-processing,and *** also review how DL is used in phase image ***,we summarize the work in DL for PR and provide an outlook on how to better use DL to improve the reliability and efficiency of ***,we present a live-updating resource(https://***/kqwang/phase-recovery)for readers to learn more about PR.

关键词： networks phase optics

A Novel Multiple-Network Analysis Integrating Metabolomics and Pharmacology for Mechanism Study of Medicine:A Case Study of CDD-2101 Against Constipation

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Journal of Analysis and Testing 2024年第4期8卷 415-430页

作者： Jingchun Shi Li Xiang yan y.lam Ziwan Ning Jie Liu yaqi Li yujuan Zhou Lixiang Zhai Chengyuan Lin Lin Zhu Zhaoxiang Bian Centre for Chinese Herbal Medicine Drug Development Limited Hong Kong Baptist University School of Chinese Medicine Hong Kong Baptist University State Key Laboratory of Environmental and Biological Analysis Department of ChemistryHong Kong Baptist University Department of Medicine School of Clinical MedicineLKS Faculty of MedicineThe University of Hong Kong

Constipation aff ects more than 14% of the global population with complex pathogenesis. Compound Traditional Chinese medicines(TCM), such as CDD-2101, a manufactured version of a time-tested TCM, hold great promise for constipation treatment due to the multiple-component-multiple-target strategy. Here, a novel multiple network analysis based on metabolomics and network pharmacology was developed to decipher the complex interplays between CDD-2101 and constipation. First, CDD-2101 alleviated constipation in a loperamide-induced acute constipation mice model and no adverse eff ect was observed. Then, fecal metabolomics and phytochemistry profi les were conducted by liquid chromatography-mass spectrometry analysis. The untargeted metabolomics built a metabolomic network related to signifi cantly modulated pathways during the constipation alleviation, including bile acid secretion, steroid hormone biosynthesis, glycerophospholipid metabolism, and linoleic acid metabolism. Based on the phytochemistry, network pharmacology predicted similar modulated pathways and built a hub-target network including retinoid X receptor alpha(RXRA), cytochrome P450 1A1(CyP1A1), cytochrome P450 1A2(CyP1A2), and phospholipase A2-IVA(PLA2G4). Third, integrated networks were built to select the key pathways and targets, as well as the key ingredients, including rhein, hesperetin, albifl orin, and magnolol from the TCM, which were corroborated by molecular docking, in vitro enzyme assays, and targeted metabolomics results. Finally, an integrated network was built to elucidate the multi-ingredient-multi-symptom linkage during the treatment. In conclusion, the novel multiple-network analysis revealed the complex “multi-component-multi-target-multi-pathway” mechanisms of CDD-2101 against constipation. Our work provides insight into the understanding of active compounds and pharmacological mechanisms, contributing to the development of natural medicines.

关键词： Constipation Mass spectrometry Medicine Metabolomics Network pharmacology

Enhanced depth resolution in optical scanning holography using a configurable pupil

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Photonics Research 2014年第2期2卷 64-70页

作者： Haiyan Ou Ting-Chung Poon Kenneth K.y.Wong Edmund y.lam Department of Electrical and Electronic Engineering University of Hong KongPokfulamHong KongChina Institute of Applied Physics University of Electronic Science and Technology of China610054ChengduChina Bradley Department of Electrical and Computer Engineering Virginia TechBlacksburgVirginia 24061USA

The optical scanning holography(OSH)technique can capture all the three-dimensional volume information of an object in a hologram via a single raster *** digital hologram can then be processed to reconstruct individual sectional images of the *** this paper,we present a scheme to reconstruct sectional images in OSH with enhanced depth resolution,where a spatial light modulator(SLM)is adopted as a configurable point *** switching the SLM between two states,different Fresnel zone plates(FZPs)are generated based on the same optical *** extra information provided by different FZPs,a depth resolution at 0.7μm can be achieved.

关键词： resolution sectional Fresnel

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光学扫描全息术研究进展

光学学报 2020年第1期40卷 146-156页

作者：任振波林彥民西北工业大学物理科学与技术学院超常条件材料物理与化学教育部重点实验室陕西省光信息技术重点实验室陕西西安710129 香港大学工程学院电机与电子工程系香港

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... 详细信息

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。

关键词：成像系统数字全息术光学扫描全息术计算成像图像重建

Enhancing image resolution of confocal fluorescence microscopy with deep learning

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PhotoniX 2023年第1期4卷 652-673页

作者： Boyi Huang Jia Li Bowen yao Zhigang yang Edmund y.lam Jia Zhang Wei yan Junle Qu Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Department of Electrical and Electronic Engineering University of Hong KongPokfulamHong KongSARChina

Super-resolution optical imaging is crucial to the study of cellular *** super-resolution fluorescence microscopy is restricted by the need of special fluorophores or sophisticated optical systems,or long acquisition and computational *** this work,we present a deep-learning-based super-resolution technique of confocal *** devise a two-channel attention network(TCAN),which takes advantage of both spatial representations and frequency contents to learn a more precise mapping from low-resolution images to high-resolution *** scheme is robust against changes in the pixel size and the imaging setup,enabling the optimal model to generalize to different fluorescence microscopy modalities unseen in the training *** algorithm is validated on diverse biological structures and dual-color confocal images of actin-microtubules,improving the resolution from~230 nm to~110 *** but not least,we demonstrate live-cell super-resolution imaging by revealing the detailed structures and dynamic instability of microtubules.

关键词： Super-resolution fluorescence microscopy Image resolution enhancement Deep learning Generative adversarial network

Hybrid brightfield and darkfield transport of intensity approach for high-throughput quantitative phase microscopy

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Advanced Photonics 2022年第5期4卷 15-26页

作者： Linpeng Lu Jiaji Li yefeng Shu Jiasong Sun Jie Zhou Edmund y.lam Qian Chen Chao Zuo Nanjing University of Science and Technology Smart Computational Imaging Laboratory(SCILab)NanjingChina Nanjing University of Science and Technology School of Electronic and Optical EngineeringNanjingChina Jiangsu Key Laboratory of Spectral Imaging&Intelligent Sense NanjingChina Nanjing University of Science and Technology Smart Computational Imaging Research Institute(SCIRI)NanjingChina The University of Hong Kong Department of Electrical and Electronic EngineeringPokfulamHong KongChina

Transport of intensity equation(TIE)is a well-established non-interferometric phase retrieval approach that enables quantitative phase imaging(QPI)by simply measuring intensity images at multiple axially displaced *** advantage of a TIE-based QPI system is its compatibility with partially coherent illumination,which provides speckle-free imaging with resolution beyond the coherent diffraction ***,TIE is generally implemented with a brightfield(BF)configuration,and the maximum achievable imaging resolution is still limited to the incoherent diffraction limit(twice the coherent diffraction limit).It is desirable that TIE-related approaches can surpass this limit and achieve high-throughput[high-resolution and wide field of view(FOV)]*** propose a hybrid BF and darkfield transport of intensity(HBDTI)approach for highthroughput quantitative phase *** through-focus intensity stacks corresponding to BF and darkfield illuminations are acquired through a low-numerical-aperture(NA)objective *** high-resolution and large-FOV complex amplitude(both quantitative absorption and phase distributions)can then be synthesized based on an iterative phase retrieval algorithm taking the coherence model decomposition into *** effectiveness of the proposed method is experimentally verified by the retrieval of the USAF resolution target and different types of biological *** experimental results demonstrate that the half-width imaging resolution can be improved from 1230 nm to 488 nm with 2.5×expansion across a 4×FOV of 7.19 mm2,corresponding to a 6.25×increase in space-bandwidth product from∼5 to∼30.2 *** contrast to conventional TIE-based QPI methods where only BF illumination is used,the synthetic aperture process of HBDTI further incorporates darkfield illuminations to expand the accessible object frequency,thereby significantly extending the maximum available resolution from 2NA to∼5NA with a∼5×promotion of the coherent diffra

关键词： transport of intensity equation phase retrieval darkfield imaging high-throughput microscopy