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Joint contrast optimization and object segmentation in active polarimetric images

OPTICS LETTERS 2012年第16期37卷 3321-3323页

作者： Anna, Guillaume Bertaux, Nicolas Galland, Frederic Goudail, Francois Dolfi, Daniel Univ Paris 11 CNRS Inst Opt Lab Charles FabryUMR 8501 F-91127 Palaiseau France Aix Marseille Univ Inst Fresnel Ecole Cent Marseille CNRS F-13013 Marseille France Thales Res & Technol France RD128 F-91767 Palaiseau France

We present a method for automatic target detection based on the iterative interplay between an active polarimetric imager with adaptive capabilities and a snake-based image segmentation algorithm. It successfully addresses the difficult situations where the target and the background differ only by their polarimetric properties. This method illustrates the benefits of integrating digital processing algorithms at the heart of the image acquisition process rather than using them only for postprocessing. (C) 2012 Optical Society of America

关键词： image processing image processing algorithms Light scattering Medical imaging Mueller matrices Polarimetric imaging

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Wide measurement range scanning heterodyne interferometer utilizing astigmatic position sensing scheme

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OPTICS LETTERS 2011年第16期36卷 3112-3114页

作者： Park, Youngkyu Kim, Kyoung-Eop Kim, Seong-Jin Park, June-Gyu Joo, Young-Hun Shin, Bu Hyun Lee, Seung-Yop Cho, Kyuman Sogang Univ Dept Phys Seoul 121742 South Korea Sogang Univ Dept Mech Engn Seoul 121742 South Korea

A scanning heterodyne I/Q-interferometer scheme is proposed to overcome phase ambiguity caused by the periodic nature of its phase-dependent signal. A position sensing scheme using an astigmatic method in the confocal arrangement has been interfaced to the interferometer to retrieve the real phase value during a scanning process. The experimental results show that the vertical measurement range can be expanded up to 16 mu m. The potential of this interferometer on the scanning microscopy of a rough surface is discussed. (C) 2011 Optical Society of America

关键词： image processing algorithms Phase measurement Phase unwrapping Position sensing Scanning microscopy Three dimensional image processing

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Statistics of the depth-scan photocurrent in time-domain optical coherence tomography

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS image SCIENCE AND VISION 2008年第1期25卷 16-20页

作者： Sherif, Sherif S. Rosa, Carla C. Flueraru, Costel Chang, Shoude Mao, Youxin Podoleanu, Adrian G. Natl Res Council Canada Inst Microstruct Sci Ottawa ON K1A 0R6 Canada Univ Porto Inst Engn Sistemas & Computadores Oporto Portugal Univ Kent Sch Phys Sci Appl Opt Grp Canterbury CT2 7NH Kent England

We derive the time-variant second-order statistics of the depth-scan photocurrent in time-domain optical coherence tomography (TD-OCT) systems using polarized thermal light sources and superluminescent diodes (SLDs). Since the asymptotic-joint-probability-distribution function (JPDF) of the photocurrent due to polarized thermal light is Gaussian and the signal-noise-ratio in TD-OCT is typically high (> 80 dB), the JPDF of the depth-scan photocurrent could be approximated as a Gaussian random process that is completely determined by its second-order statistics. We analyze both direct and differential light detection schemes and include the effect of electronic thermal fluctuations. Our results are a necessary prerequisite for future development of statistical image processing techniques for TD-OCT. (c) 2007 Optical Society of America.

关键词： Digital image processing image processing algorithms Medical imaging Optical coherence tomography Speckle reduction Stochastic processes

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Aperture-type terahertz near-field imaging with a cylindrical frustum-shaped plastic probe

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APPLIED OPTICS 2021年第21期60卷 6308-6312页

作者： Wang, Nan Chang, Tianying Cui, Hong-Liang Jilin Univ Coll Instrumentat & Elect Engn Changchun 130012 Jilin Peoples R China Chinese Acad Sci Shenzhen Inst Adv Technol Shenzhen 518055 Guangdong Peoples R China

We designed an aluminum-coated plastic probe made from the combination of cylinder and a frustum of a cone for terahertz near-field imaging. The bunching width of the probe is 12 mu m and the electric field intensity enhancement factor just outside the probe tip reaches up to 25. An imaging resolution obtained through near-field imaging experiments on a variety of targets, including narrow metals and narrow media, is 6 mu m (lambda/450) at 0.11 THz. By adopting an adaptive threshold segmentation image processing algorithm that combines Hilbert scanning and wavelet transform, the influence of a large area of metal near the imaging area on the imaging result is successfully suppressed. Imaging of a scratch on the plastic substrate makes the new probe feasible for quality identification of nonmetallic cultural relics. (C) 2021 Optical Society of America

关键词： Electric fields image processing image processing algorithms Medical imaging Spatial resolution Wavelet transforms

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Fast, sub-pixel accurate, displacement measurement method: optical and terahertz systems

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OPTICS LETTERS 2020年第24期45卷 6611-6614页

作者： Wan, Min Healy, John J. Sheridan, John T. Univ Coll Dublin Coll Architecture & Engn Sch Elect & Elect Engn Dublin 4 Ireland

A novel (to the best of our knowledge), fast method to measure in-plane object motion in 1D with sub-pixel accuracy which complements the correlation technique is proposed. The method is verified experimentally using both visible and terahertz images. The absolute sum of grey level accumulated change is used to quantify object motion. The method requires calibration for each target, but only addition and. subtraction operations. This results in a decrease of two orders of magnitude in the computation time. (C) 2020 Optical Society of America

关键词： Diode pumped lasers image processing algorithms image quality Optical measurement Ptychography Terahertz imaging

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Algorithm for detecting artificial objects against natural backgrounds

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JOURNAL OF OPTICAL TECHNOLOGY 2018年第6期85卷 338-342页

作者： Pronin, S., V Russian Acad Sci IP Pavlov Inst Physiol St Petersburg Russia

This paper describes an algorithm for distinguishing between images of two classes of objects: artificial and natural. An approximation to the image is generated using graphical elements similar to the receptor fields of neurons in the primary visual cortex (Zone VI). We show that the approximation-error distribution for natural-object images lies at higher values of the approximation error than that for artificial-object images. This difference makes it possible to detect artificial objects against natural backgrounds. (C) 2018 Optical Society of America

关键词： Bandpass filters image processing algorithms image recognition Nonlinear spatial filtering Spatial frequency Visual system

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Optical topography of rough surfaces using vortex localization of fluorescent markers

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OPTICS LETTERS 2020年第16期45卷 4468-4471页

作者： Schovanek, Petr Bouchal, Petr Bouchal, Zdenek Palacky Univ Dept Opt 17 Listopadu 1192-12 Olomouc 77146 Czech Republic Meopta Optika Sro Kabelikova 1 Prerov 75002 Czech Republic Brno Univ Technol Fac Mech Engn Inst Phys Engn Tech 2 Brno 61669 Czech Republic Brno Univ Technol Cent European Inst Technol Purkynova 656-123 Brno 61200 Czech Republic

Measuring rough surfaces is challenging because the proven topographic methods are impaired by the adverse effects of diffuse light. In our method, the measured surface is marked by fluorescent nanobeads allowing a complete suppression of diffuse light by bandpass filtering. Light emitted by each fluorescent bead is shaped to a double-helix point spread function used for three-dimensional bead localization on the surface. This non-interferometric measurement of rough surface topography is implemented in a vibration resistant setup. The comparison of our method with vertical scanning interferometry shows that a commercial profiler is surpassed when ground glass surfaces with steep slopes are measured. (C) 2020 Optical Society of America

关键词： Bandpass filters Fluorescent markers Green fluorescent protein image processing algorithms Phase unwrapping Vibration

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Modeling of the optical system illuminated by quasi-monochromatic spatially incoherent light: new numerical approach

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OPTICS LETTERS 2012年第22期37卷 4723-4725页

作者： Czerwinski, A. Kakarenko, K. Sypek, M. Makowski, M. Ducin, I. Suszek, J. Kolodziejczyk, A. Bomba, J. Warsaw Univ Technol Fac Phys PL-00662 Warsaw Poland

This Letter presents a new method for modeling of complex optical setups illuminated by quasi monochromatic spatially incoherent light. The algorithm provides better performance and quality than other modeling methods both for isoplanatic and nonisoplanatic systems. The algorithm maintains energy relations, image orientation, and magnification of the system. Computer modeling and experimental results are presented. (C) 2012 Optical Society of America

关键词： Computer simulation image processing algorithms Imaging systems Point spread function Speckle patterns Thermal imaging

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PZT calibration

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OPTIK 2013年第17期124卷 2803-2806页

作者： Ionita, Bogdan Florin Garoi, Florin Logofatu, Petre Catalin Apostol, Dan GSI Darmstadt Helmholtz Ctr Heavy Ion Res D-64220 Darmstadt Germany Natl Inst Laser Plasma & Radiat Phys Lasers Dept Magurele 077125 Romania

One important source of error in phase-shift interferometry consists of a nonuniform application of phase steps, due, for example, to a nonlinear piezoelectric effect in the phase shifter. We developed a method for inline PZT calibration using a video camera for acquiring interferograms and an ATI Radeon X1650 video card for frame processing. The PZT was calibrated over a voltage range of 40 V and a displacement range of 11 mu m. We acquired 801 interferograms in a Twyman-Green interferometer and a 801 x 801 matrix computed from the subtraction of each interferogram from every other interferogram was obtained and used for calibration. The speed and accuracy of frame processing of the video card was compared to the results obtained by an Intel QuadCore processor. In terms of accuracy there are no significant differences, but the processing using the video card was similar to 5 times faster than the processing using the processor. The processing took similar to 5 min and we obtained a dispersion of similar to 10 nm when we fitted the displacement of the PZT to a polynomial of degree 5 in voltage. (C) 2012 Elsevier GmbH. All rights reserved.

关键词： Phase-shift interferometry image processing algorithms

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Chromophoric cerium oxide nanoparticle-loaded sucking disk-type strip sensor for optical measurement of glucose in tear fluid

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BIOMATERIALS RESEARCH 2023年第1期27卷 1-13页

作者： Park, Sijin Nam, Dong Yeon Jeon, Hee-Jae Han, Jae Hoon Jang, Dawon Hwang, Juil Park, Yeong-Seo Han, Young-Geun Choy, Young Bin Lee, Dong Yun Hanyang Univ Coll Engn Dept Bioengn 222 Wangsimni Ro Seoul 04763 South Korea Hanyang Univ BK FOUR Biopharmaceut Innovat Leader Educ & Res Gr 222 Wangsimni Ro Seoul 04763 South Korea Seoul Natl Univ Coll Engn Interdisciplinary Program Bioengn 1 Gwanak Ro Seoul 08826 South Korea Kangwon Natl Univ Dept Mech & Mechatron Engn 1 Gangwondaehak Gil Chunchon 24341 South Korea Hanyang Univ Dept Phys Coll Nat Sci 222 Wangsimni Ro Seoul 04763 South Korea Seoul Natl Univ Dept Biomed Engn Coll Med 101 Daehak Ro Seoul 03080 South Korea Seoul Natl Univ Inst Med & Biol Engn Med Res Ctr 101 Daehak Ro Seoul 03080 South Korea Hanyang Univ Inst Nano Sci & Technol INST 222 Wangsimni Ro Seoul 04763 South Korea Hanyang Univ Inst Bioengn & Biopharmaceut Res IBBR 222 Wangsimni Ro Seoul 04763 South Korea Elixir Pharmatech Inc 222 Wangsimni Ro Seoul 04763 South Korea

BackgroundNoninvasive monitoring of tear glucose levels can be convenient for patients to manage their diabetes mellitus. However, there are issues with monitoring tear glucose levels, such as the invasiveness of some methods, the miniaturization, inaccuracy, or the high cost of wearable devices. To overcome the issues, we newly designed a sucking disk-type (SD) strip biosensor that can quickly suck tear fluid and contains cerium oxide nanoparticle (CNP) that causes a unique color change according to the glucose level of the tear without complicated electronic *** SD strip biosensor composed of three distinct parts (tip, channel, and reaction chamber) was designed to contain the sensing paper, onto which tear fluid can be collected and delivered. The sensing paper treated with CNP/APTS (aminopropyltriethoxysilane) /GOx (glucose oxidase) was characterized. Then we carried out the reliability of the SD strip biosensor in the diabetic rabbit animals. We quantitatively analyzed the color values of the SD strip biosensor through the colorimetric analysis *** contacted the inferior palpebral conjunctiva (IPC) of a diabetic rabbit eye using an SD strip biosensor to collect tears without eye irritation and successfully verified the performance and quantitative efficacy of the sensor. An image processing algorithm that can optimize measurement accuracy is developed for accurate color change measurement of SD strip biosensors. The validation tests show a good correlation between glucose concentrations measured in the tear and *** findings demonstrate that the CNP-embedded SD strip biosensor and the associated image processing can simply monitor tear glucose to manage diabetes mellitus.

关键词： Sucking disk-type (SD) strip biosensor Cerium oxide nanoparticles (CNPs) image processing algorithms Tear glucose Diabetes

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