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Multi-transmitter aperture synthesis

OPTICS EXPRESS 2010年第24期18卷 24937-24945页

作者： Rabb, David J. Jameson, Douglas F. Stafford, Jason W. Stokes, Andrew J. USAF Res Lab Sensors Directorate Wright Patterson AFB OH 45433 USA

Multi-transmitter aperture synthesis is a method in which multiple transmitters can be used to improve resolution and contrast of distributed aperture systems. Such a system utilizes multiple transmitter locations to interrogate a target from multiple look angles thus increasing the angular spectrum content captured by the receiver aperture array. Furthermore, such a system can improve the contrast of sparsely populated receiver arrays by capturing field data in the region between sub-apertures by utilizing multiple transmitter locations. This paper discusses the theory behind multi-transmitter aperture synthesis and provides experimental verification that imagery captured using multiple transmitters will provide increased resolution.

关键词： Aperture synthesis Holographic techniques image processing algorithms image resolution Speckle noise Synthesis methods

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High-precision displacement measurement algorithm based on a depth fusion of grating projection pattern

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APPLIED OPTICS 2022年第4期61卷 1049-1056页

作者： Yu, Hai Wan, Qiuhua Lu, Xinran Du, Yingcai Liang, Lihui Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China

Displacement measurement based on an image recognition algorithm has more advantages in the field of displacement measurement. Due to the uncertainty of image location, the accuracy of the displacement measurement algorithm studied in the previous stage is limited. To improve the accuracy of image-type displacement measurement, a high-precision displacement measurement algorithm based on depth fusion of the grating projection pattern is proposed. First, a line-scan image sensor and parallel light source are placed on both sides of the calibration grating. The marking pattern on the calibration grating is projected onto the image sensor through illumination of the parallel light source to realize the projection imaging. Then, the centroid algorithm is used to calculate the centroid of each line in the collected image, and the mean value of the centroid group is determined. Finally, a linear function is used to fit multiple centroids to calculate the endpoints of the subdivision region, and the subdivision operation is carried out according to a ratio algorithm. To test the performance of the proposed algorithm, a linear displacement measurement device with a 250 mm range and an angular displacement measurement device with a 100 mm diameter grating are both used for experiments. After testing, the linear measurement accuracy of the proposed algorithm is improved from 4.63 to 1.26 mu m, and the angular displacement measurement accuracy is enhanced from 8.87 to 2.88 ''. The research in this paper provides a theoretical basis for high-performance displacement measurement. (C) 2022 Optica Publishing Group

关键词： Digital image processing image detection systems image processing algorithms image recognition algorithms image sensors Spatial resolution

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Adaptive optics implementation with a Fourier reconstructor

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APPLIED OPTICS 2007年第4期46卷 574-580页

作者： Glazer, Oded Ribak, Erez N. Mirkin, Leonid Technion Israel Inst Technol Fac Mech Engn IL-32000 Haifa Israel Technion Israel Inst Technol Fac Phys IL-32000 Haifa Israel

Adaptive optics takes its servo feedback error cue from a wavefront sensor. The common Hartmann-Shack spot grid that represents the wavefront slopes is usually analyzed by finding the spot centroids. In a novel application, we used the Fourier decomposition of a spot pattern to find deviations from grid regularity. This decomposition was performed either in the Fourier domain or in the image domain, as a demodulation of the grid of spots. We analyzed the system, built a control loop for it, and tested it thoroughly. This allowed us to close the loop on wavefront errors caused by turbulence in the optical system.

关键词： Adaptive optics Deformable mirrors image processing algorithms image quality Optical turbulence Phase compensation

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Precise calibration of pupil images in pyramid wavefront sensor

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APPLIED OPTICS 2017年第12期56卷 3281-3286页

作者： Liu, Yong Mu, Quanquan Cao, Zhaoliang Hu, Lifa Yang, Chengliang Xuan, Li Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys State Key Lab Appl Opt Changchun 130033 Peoples R China Univ Chinese Acad Sci Beijing 100039 Peoples R China

The pyramid wavefront sensor (PWFS) is a novel wavefront sensor with several inspiring advantages compared with Shack-Hartmann wavefront sensors. The PWFS uses four pupil images to calculate the local tilt of the incoming wavefront. Pupil images are conjugated with a telescope pupil so that each pixel in the pupil image is diffraction-limited by the telescope pupil diameter, thus the sensing error of the PWFS is much lower than that of the Shack-Hartmann sensor and is related to the extraction and alignment accuracy of pupil images. However, precise extraction of these images is difficult to conduct in practice. Aiming at improving the sensing accuracy, we analyzed the physical model of calibration of a PWFS and put forward an extraction algorithm. The process was verified via a closed-loop correction experiment. The results showed that the sensing accuracy of the PWFS increased after applying the calibration and extraction method. (c) 2017 Optical Society of America

关键词： Adaptive optics image processing algorithms Large telescopes Liquid crystal modulators Pupil Wavefront aberrations

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Analysis of cellular objects through diffraction images acquired by flow cytometry

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OPTICS EXPRESS 2013年第21期21卷 24819-24828页

作者： Zhang, Jun Feng, Yuanming Moran, Marina S. Lu, Jun Q. Yang, Li V. Sa, Yu Zhang, Ning Dong, Lixue Hu, Xin-Hua Tianjin Univ Dept Biomed Engn Tianjin 300072 Peoples R China Tianjin Med Univ Canc Inst & Hosp Dept Radiat Oncol Tianjin 300060 Peoples R China E Carolina Univ Dept Phys Greenville NC 27858 USA E Carolina Univ Brody Sch Med Dept Oncol Greenville NC 27834 USA

It was found that the diffraction images acquired along the side scattering directions with objects in a cell sample contain pattern variations at both the global and local scales. We show here that the global pattern variation is associated with the categorical size and morphological heterogeneity of the imaged objects. An automated image processing method has been developed to separate the acquired diffraction images into three types of global patterns. Combined with previously developed method for quantifying local texture pattern variations, the new method allows fully automated analysis of diffraction images for rapid and label-free classification of cells according to their 3D morphology. (C) 2013 Optical Society of America

关键词： Forward scattering image analysis image processing image processing algorithms Speckle patterns Systems design

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Label-free non-invasive subwavelength-resolution imaging using yeast cells as biological lenses

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BIOMEDICAL OPTICS EXPRESS 2021年第11期12卷 7113-7121页

作者： Jiang, Chunlei Yue, Hangyu Yan, Bing Dong, Taiji Cui, Xiangyu Chen, Peng Wang, Zengbo Northeast Petr Univ Coll Elect & Informat Engn Daqing 163318 Peoples R China Bangor Univ Sch Comp Sci & Elect Engn Dean St Bangor LL57 1UT Gwynedd Wales Chinese Acad Sci Ctr Opt Hlth Suzhou Inst Biomed Engn & Technol 88 Keling St Suzhou 215163 Jiangsu Peoples R China Northeast Petr Univ Coll Comp & Informat Technol Daqing 163318 Peoples R China

There is a growing interest to use live cells to replace the widely used non-biological microsphere lenses. In this work, we demonstrate the use of yeast cells for such imaging purpose. Using fiber-based optical trapping technique, we trap a chain of three yeast cells and bring them to the vicinity of imaging objects. These yeast cells work as near-field magnifying lenses and simultaneously pick up the sub-diffraction information of the nanoscale objects under each cell and project them into the far-field. The experimental results demonstrated that Blu-ray disc of 100 nm feature can be clearly resolved in a parallel manner by each cell. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： image processing algorithms image quality Imaging techniques Optical imaging Scanning electron microscopy White light

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Multi-Megahertz OCT: High quality 3D imaging at 20 million A-scans and 4.5 GVoxels per second

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OPTICS EXPRESS 2010年第14期18卷 14685-14704页

作者： Wieser, Wolfgang Biedermann, Benjamin R. Klein, Thomas Eigenwillig, Christoph M. Huber, Robert Univ Munich Fak Phys Lehrstuhl BioMol Opt D-80538 Munich Germany

We present ultra high speed optical coherence tomography (OCT) with multi-megahertz line rates and investigate the achievable image quality. The presented system is a swept source OCT setup using a Fourier domain mode locked (FDML) laser. Three different FDML-based swept laser sources with sweep rates of 1, 2.6 and 5.2MHz are compared. Imaging with 4 spots in parallel quadruples the effective speed, enabling depth scan rates as high as 20.8 million lines per second. Each setup provides at least 98dB sensitivity and similar to 10 mu m resolution in tissue. High quality 2D and 3D imaging of biological samples is demonstrated at full scan speed. A discussion about how to best specify OCT imaging speed is included. The connection between voxel rate, line rate, frame rate and hardware performance of the OCT setup such as sample rate, analog bandwidth, coherence length, acquisition dead-time and scanner duty cycle is provided. Finally, suitable averaging protocols to further increase image quality are discussed. (C) 2010 Optical Society of America

关键词： Biological imaging High speed imaging image processing algorithms image quality Point spread function Three dimensional imaging

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Detecting the morphology of single graphene sheets by dual channel sampling plasmonic imaging

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OPTICS EXPRESS 2020年第4期28卷 4686-4693页

作者： Wei, Ruxue Jiang, Liwen Sun, Xuqing Liu, Hongyao Wang, Xue Wang, Chang Lu, Xinchao Huang, Chengjun Chinese Acad Sci Inst Microelect Beijing 100029 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Tianjin Univ Ctr Terahertz Waves Coll Precis Instrument & Optoelect Engn Tianjin 300072 Peoples R China Tianjin Univ Key Lab Optoelect Informat & Technol Minist Educ Tianjin 300072 Peoples R China

Due to their excellent physical and chemical properties, graphene sheets are widely used in industry, which makes detection important to guarantee their performance. Atomic force microscopy, scanning electron microscopy, and Raman spectroscopy are the most common detection methods, which is either time-consuming or easily destructive. In this work, we presented a fast and nondestructive method to detect single graphene sheets by using plasmonic imaging. Dual channel sampling plasmonic imaging combining the image processing algorithm is used to improve the deterioration from propagation length of surface plasmon polaritons and reconstruct the complete morphology of single graphene sheets. The fast and nondestructive detection method paves the way to applications of graphene, and can be extended to the detections of two-dimensional materials, single biological molecule, viruses, and nanomaterials. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Beam expanders Chemical vapor deposition High power lasers image processing image processing algorithms Scanning electron microscopy

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Accurate 3D autostereoscopic display using optimized parameters through quantitative calibration

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS image SCIENCE AND VISION 2017年第5期34卷 804-812页

作者： Fan, Zhencheng Chen, Guowen Xia, Yan Huang, Tianqi Liao, Hongen Tsinghua Univ Sch Med Dept Biomed Engn Beijing 100084 Peoples R China

Quality of three-dimensional (3D) autostereoscopic displays is mainly influenced by the mismatch between the optical apparatus setups and image generation algorithms. In this paper, we take the optical apparatus setups into consideration and present an accurate 3D autostereoscopic display method using optimized parameters through quantitative calibration. Rotational and translational alignments are operated quantitatively to rectify the optical apparatus. In addition, the main parameters in a 3D display are evaluated for accurate 3D image rendering. Using the proposed method, the 3D autostereoscopic display can be calibrated quantitatively and provide 3D images with accurate spatial information. Experiments verified the availability and feasibility of the proposed method. (C) 2017 Optical Society of America

关键词： Crystalline lens image processing image processing algorithms Integral photography Refractive index Three dimensional displays

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Super-resolution fluorescence blinking imaging using modified Fourier ptychography

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OPTICS EXPRESS 2018年第3期26卷 2740-2748页

作者： Wu, Jingjing Yu, Bin Zhang, Saiwen Li, Siwei Wang, Xuehua Chen, Danni Qu, Junle Shenzhen Univ Coll Optoelect Engn Minist Educ & Guangdong Prov Key Lab Optoelect Devices & Syst Shenzhen 518060 Peoples R China Shenzhen Univ Coll Optoelect Engn Shenzhen Key Lab Micro Nano Measuring & Imaging B Shenzhen 518060 Peoples R China

In this paper, we propose a new super-resolution imaging technique based on fluorescence blinking (SRFB). Contrary to structured illumination microscopy (SIM), SRFB considers the time-varying fluorescence distribution under a suitable density as the varying illuminated speckle pattern, and therefore, external speckle patterns or diffusers are not required. With several images recorded at different times, a super-resolution image can be obtained through an iterative algorithm modified from Fourier ptychography. Recorded image sequences in a microscopy imaging experiment based on photo switching or fluorescence blinking effects, such as STORM and SOFI, can be handled with SRFB and used to recover a super-resolution image. The simulation and experimental results confirm that the SRFB scheme can surpass the diffraction limit by a factor greater than two. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Diffraction limit image processing algorithms Imaging techniques Optical imaging Speckle patterns Structured illumination microscopy

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