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Robust silicon-on-insulator adiabatic splitter optimized by metamodeling

APPLIED OPTICS 2017年第8期56卷 2047-2052页

作者： Hassan, Karim Durantin, Cedric Hugues, Vincent Szelag, Bertrand Gliere, Alain Univ Grenoble Alpes CEA LETI Minatec Campus F-38054 Grenoble France

A robust integrated power splitter based on a silicon-on-insulator adiabatic coupler configuration is demonstrated. The power separation is achieved by a slow and simultaneous change of phase and coupling constants. The geometrical parameters of the device are determined thanks to a metamodel-based iterative optimization strategy. Solving the multiple parameter problem together with a realistic bandwidth constraint provides a clear improvement of the power splitting stability. The robustness is confirmed experimentally on a single device and at the wafer scale. (C) 2017 Optical Society of America

关键词： Complementary metal oxide semiconductors computation methods Finite element method Optical directional couplers Optical transceivers Wavelength division multiplexing

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Precise locating approach of the beacon based on gray gradient segmentation interpolation in satellite optical communications

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APPLIED OPTICS 2017年第7期56卷 1826-1832页

作者： Wang, Qiang Liu, Yuefei Chen, Yiqiang Ma, Jing Tan, Liying Yu, Siyuan Harbin Inst Technol Natl Key Lab Tunable Laser Technol Harbin 150001 Peoples R China

Accurate location computation for a beacon is an important factor of the reliability of satellite optical communications. However, location precision is generally limited by the resolution of CCD. How to improve the location precision of a beacon is an important and urgent issue. In this paper, we present two precise centroid computation methods for locating a beacon in satellite optical communications. First, in terms of its characteristics, the beacon is divided into several parts according to the gray gradients. Afterward, different numbers of interpolation points and different interpolation methods are applied in the interpolation area;we calculate the centroid position after interpolation and choose the best strategy according to the algorithm. The method is called a "gradient segmentation interpolation approach," or simply, a GSI (gradient segmentation interpolation) algorithm. To take full advantage of the pixels of the beacon's central portion, we also present an improved segmentation square weighting (SSW) algorithm, whose effectiveness is verified by the simulation experiment. Finally, an experiment is established to verify GSI and SSW algorithms. The results indicate that GSI and SSW algorithms can improve locating accuracy over that calculated by a traditional gray centroid method. These approaches help to greatly improve the location precision for a beacon in satellite optical communications. (C) 2017 Optical Society of America

关键词： Algorithms computation methods Interpolation Laser communications Nonlinear spatial filtering Optical communications

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computational integral imaging reconstruction of perspective and orthographic view images by common patches analysis

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OPTICS EXPRESS 2017年第18期25卷 21887-21900页

作者： Yan, Zhiqiang Yan, Xingpeng Jiang, Xiaoyu Ai, Lingyu Acad Armored Forces Engn Dept Informat Engn Beijing 100072 Peoples R China Kwangwoon Univ HoloDigilog Human Media Res Ctr HoloDigilog Seoul 139701 South Korea

A novel method to computationally reconstruct perspective and orthographic view images with full resolution of a recording device from a single integral photograph is proposed. Firstly, a group of image slices that contain full yet redundant information to reconstruct the view image are generated, and the object surface is divided into pieces by the points that correspond to the centers of image slices. Secondly, the image slices that contribute to the pieces are extracted and redundant information embedded in them are figured out by common patches analysis. Finally, the view image is reconstructed by excluding the redundant information and resampling with maximum sampling rate. Each piece of the object surface is represented with 9 patches at most from 4 adjacent elemental images, and view images with high quality are reconstructed. Both simulations and experiments verify the validity of the method. (C) 2017 Optical Society of America

关键词： computation methods Image display Image processing Image reconstruction Integral photography Light fields

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Improved computation of the adaptation coefficient in the CIE system of mesopic photometry

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OPTICS EXPRESS 2017年第15期25卷 18365-18377页

作者： Gao, Cheng Xu, Yang Wang, Zhifeng Melgosa, Manuel Pointer, Michael Luo, Ming Ronnier Xiao, Kaida Li, Changjun Univ Sci & Technol Liaoning Sch Elect & Informat Engn Anshan 114051 Peoples R China Univ Granada Fac Sci Dept Opt E-18071 Granada Spain Univ Leeds Sch Design Leeds LS2 9JT W Yorkshire England Zhejiang Univ State Key Lab Modern Opt Instrumentat Hangzhou 310058 Zhejiang Peoples R China Wenzhou Univ Coll Phys & Informat Engn Wenzhou 325035 Peoples R China

New values of parameters a and b are proposed for the CIE system of mesopic photometry MES2 [CIE Publication 191: 2010], because from the original values this model may have no solution or multi-solutions. From the new values of parameters a and b it is shown that the CIE MES2 system has a unique solution. The difference however, between the original and the new values of parameters a and b is very small and the changes do not affect previous conclusions based on the MES2 model. To compute such a solution, we propose a Bisection-Newton method which exhibits fast convergence (8 iterations in the worst case), and improves the fixed-point method recommended by the CIE MES2 system, which has convergence problems for high values of the photopic luminance and very high values of the scotopic/photopic ratio. Comparative results for the fixed-point method, the Bisection method, the Newton method, and the Bisection-Newton method, in terms of the number of iterations necessary for convergence and the computation time used, are reported. (C) 2017 Optical Society of America

关键词： Color rendering computation methods Light sources Photoreceptors Vision adaptation Visual system

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The FLAME-slab method for electromagnetic wave scattering in aperiodic slabs

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OPTICS EXPRESS 2017年第26期25卷 32602-32617页

作者： Mansha, Shampy Tsukerman, Igor Chong, Y. D. Nanyang Technol Univ Sch Phys & Math Sci Div Phys & Appl Phys Singapore 637371 Singapore Univ Akron Dept Elect & Comp Engn Akron OH 44325 USA Nanyang Technol Univ Ctr Disrupt Photon Technol Singapore 637371 Singapore

The proposed numerical method, "FLAME-slab," solves electromagnetic wave scattering problems for aperiodic slab structures by exploiting short-range regularities in these structures. The computational procedure involves special difference schemes with high accuracy even on coarse grids. These schemes are based on Trefftz approximations, utilizing functions that locally satisfy the governing differential equations, as is done in the Flexible Local Approximation Method (FLAME). Radiation boundary conditions are implemented via Fourier expansions in the air surrounding the slab. When applied to ensembles of slab structures with identical short-range features, such as amorphous or quasicrystalline lattices, the method is significantly more efficient, both in runtime and in memory consumption, than traditional approaches. This efficiency is due to the fact that the Trefftz functions need to be computed only once for the whole ensemble. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： computation methods Electromagnetic scattering Fast Fourier transforms Fourier transforms Matrix methods Photonic crystal lasers

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Method for calculation and analysis of a cemented component with achromatic and aplanatic correction

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JOURNAL OF OPTICAL TECHNOLOGY 2017年第8期84卷 548-551页

作者： Ivanova, T. V. Romanova, G. E. Zhukova, T. I. Kalinkina, O. S. ITMO Univ St Petersburg Russia

This paper presents a method for calculating and analyzing a cemented component, developed on the basis of the methodology of G. G. Slyusarev. According to the given values of the main parameters P, W, and C, which determine the aberration characteristics of the system, several suitable pairs of glasses are selected that provide the required values of the third-order aberrations. For each pair, the design parameters of the cemented component are calculated, and the residual aberrations are determined according to the calculation of the real ray path. (C) 2017 Optical Society of America

关键词： Algorithms Analytical techniques Chromatic aberrations computation methods Lens design Optical systems

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A Novel Method to Compute Breathing Volumes via Motion Capture Systems: Design and Experimental Trials

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JOURNAL OF APPLIED BIOMECHANICS 2017年第5期33卷 361-365页

作者： Massaroni, Carlo Cassetta, Eugenio Silvestri, Sergio Campus Biomed Roma Univ Res Unit Measurements & Biomed Instrumentat Rome Italy

Respiratory assessment can be carried out by using motion capture systems. A geometrical model is mandatory in order to compute the breathing volume as a function of time from the markers' trajectories. This study describes a novel model to compute volume changes and calculate respiratory parameters by using a motion capture system. The novel method, ie, prism-based method, computes the volume enclosed within the chest by defining 82 prisms from the 89 markers attached to the subject chest. Volumes computed with this method are compared to spirometry volumes and to volumes computed by a conventional method based on the tetrahedron's decomposition of the chest wall and integrated in a commercial motion capture system. Eight healthy volunteers were enrolled and 30 seconds of quiet breathing data collected from each of them. Results show a better agreement between volumes computed by the prism-based method and the spirometry (discrepancy of 2.23%, R-2 =.94) compared to the agreement between volumes computed by the conventional method and the spirometry (discrepancy of 3.56%, R-2 =.92). The proposed method also showed better performances in the calculation of respiratory parameters. Our findings open up prospects for the further use of the new method in the breathing assessment via motion capture systems.

关键词： optoelectronic plethysmography breathing respiratory assessment prisms volume computation methods

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A Review of methods for Analysis of the Expected Value of Information

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MEDICAL DECISION MAKING 2017年第7期37卷 747-758页

作者： Heath, Anna Manolopoulou, Ioanna Baio, Gianluca UCL Dept Stat Sci 1-19 Torrington Pl London WC1E 7HB England

In recent years, value-of-information analysis has become more widespread in health economic evaluations, specifically as a tool to guide further research and perform probabilistic sensitivity analysis. This is partly due to methodological advancements allowing for the fast computation of a typical summary known as the expected value of partial perfect information (EVPPI). A recent review discussed some approximation methods for calculating the EVPPI, but as the research has been active over the intervening years, that review does not discuss some key estimation methods. Therefore, this paper presents a comprehensive review of these new methods. We begin by providing the technical details of these computation methods. We then present two case studies in order to compare the estimation performance of these new methods. We conclude that a method based on nonparametric regression offers the best method for calculating the EVPPI in terms of accuracy, computational time, and ease of implementation. This means that the EVPPI can now be used practically in health economic evaluations, especially as all the methods are developed in parallel with R functions and a web app to aid practitioners.

关键词： probabilistic sensitivity analysis value of information computation methods EVPPI

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Mobile Microscope for Quantitative Fluorescence Sensing Through Highly Autofluorescent and Scattering Media

Mobile Microscope for Quantitative Fluorescence Sensing Thro...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Gorocs, Zoltan Rivenson, Yair Koydemir, Hatice Ceylan Tseng, Derek Troy, Tamara L. Demas, Vasiliki Ozcan, Aydogan Univ Calif Los Angeles Dept Elect Engn Los Angeles CA 90095 USA Univ Calif Los Angeles Dept Bioengn Los Angeles CA 90095 USA Univ Calif Los Angeles Calif NanoSyst Inst CNSI Los Angeles CA 90095 USA Verily Life Sci LLC Mountain View CA 94043 USA

We created a mobile fluorescence microscope weighing <40 grams and demonstrated a computational sensing method for quantitative measurement of fluorescent dyes through highly autofluorescent, scattering and absorbi... 详细信息

ISBN: (纸本)9781943580279

关键词： computation methods Diode lasers Fluorescence microscopy Image processing Image processing algorithms Scattering media

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Ray-pathing: a generalized extension and possible alternative to conventional ray aiming

Ray-pathing: a generalized extension and possible alternativ...

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International Optical Design Conference (IODC)

作者： Greynolds, Alan W. 10741 E Placita Metate Tucson AZ 85749 USA

Given two points at opposite ends of a sequence of optical surfaces, simultaneously determine the points on each surface of the ray (i.e. path) that connects them. computationally, this requires repeated solving of sy... 详细信息

ISBN: (数字)9781510616738

ISBN: (纸本)9781510616738;9781510616721

关键词： computation methods geometric optical design stray light

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