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Depth extraction of three-dimensional objects using block matching for slice images in synthetic aperture integral imaging

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APPLIED OPTICS 2011年第29期50卷 5624-5629页

作者： Lee, Joon-Jae Lee, Byung-Gook Yoo, Hoon Dongseo Univ Dept Visual Content Pusan 617716 South Korea Keimyung Univ Dept Game Mobile Contents Taegu 705701 South Korea Sangmyung Univ Seoul 110743 South Korea

We describe a computational method for depth extraction of three-dimensional (3D) objects using block matching for slice images in synthetic aperture integral imaging (SAII). SAII is capable of providing high-resolution 3D slice images for 3D objects because the picked-up elemental images are high-resolution ones. In the proposed method, the high-resolution elemental images are recorded by moving a camera;a computational reconstruction algorithm based on ray backprojection generates a set of 3D slice images from the recorded elemental images. To extract depth information of the 3D objects, we propose a new block-matching algorithm between a reference elemental image and a set of 3D slice images. The property of the slices images is that the focused areas are the right location for an object, whereas the blurred areas are considered to be empty space;thus, this can extract robust and accurate depth information of the 3D objects. To demonstrate our method, we carry out the preliminary experiments of 3D objects;the results indicate that our method is superior to a conventional method in terms of depth-map quality. (C) 2011 Optical Society of America

关键词： computation methods Image processing Image quality Imaging systems Reconstruction algorithms Three dimensional imaging

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Probabilistic 3D object recognition and pose estimation using multiple interpretations generation

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2011年第12期28卷 2607-2618页

作者： Lu, Zhaojin Lee, Sukhan Sungkyunkwan Univ Sch Informat & Commun Engn Seoul South Korea Sungkyunkwan Univ Dept Interact Sci Seoul South Korea

This paper presents a probabilistic object recognition and pose estimation method using multiple interpretation generation in cluttered indoor environments. How to handle pose ambiguity and uncertainty is the main challenge in most recognition systems. In order to solve this problem, we approach it in a probabilistic manner. First, given a three-dimensional (3D) polyhedral object model, the parallel and perpendicular line pairs, which are detected from stereo images and 3D point clouds, generate pose hypotheses as multiple interpretations, with ambiguity from partial occlusion and fragmentation of 3D lines especially taken into account. Different from the previous methods, each pose interpretation is represented as a region instead of a point in pose space reflecting the measurement uncertainty. Then, for each pose interpretation, more features around the estimated pose are further utilized as additional evidence for computing the probability using the Bayesian principle in terms of likelihood and unlikelihood. Finally, fusion strategy is applied to the top ranked interpretations with high probabilities, which are further verified and refined to give a more accurate pose estimation in real time. The experimental results show the performance and potential of the proposed approach in real cluttered domestic environments. (C) 2011 Optical Society of America

关键词： Clouds computation methods Feature extraction Machine vision Range imaging Three dimensional imaging

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Biologically inspired framework for spatial and spectral velocity estimations

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2011年第4期28卷 713-723页

作者： Liang, Xuefeng McOwan, Peter W. Johnston, Alan Queen Mary Univ London Sch Elect Engn & Comp Sci London E1 4NS England UCL CoMPLEX London WC1H 0AP England

The multichannel gradient model (McGM) is an established, biologically plausible framework for the robust extraction of image velocity. Here we describe the McGM extension into color space and report the resulting performance improvement. Our new model, in contrast to existing approaches that process color channels separately, incorporates spectral energy measures to form a local description of the stimulus chromatic spatio-temporal structure from which we can recover both spatial and spectral velocities. We present a range of comparative experiments on synthetic and natural test data that demonstrate that our new method reduces errors and is more robust over a range of viewing environments. (c) 2011 Optical Society of America

关键词： Color spaces computation methods Motion estimation Optical flow Visual system White light

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An efficient iterative algorithm for computation of scattering from dielectric objects

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OPTICS EXPRESS 2011年第4期19卷 3304-3315页

作者： Liao, Shaolin Gopalsami, N. Venugopal, A. Heifetz, A. Raptis, A. C. Argonne Natl Lab Argonne IL 60439 USA

We have developed an efficient iterative algorithm for electromagnetic scattering of arbitrary but relatively smooth dielectric objects. The algorithm iteratively adapts the equivalent surface currents until the electromagnetic fields inside and outside the dielectric objects match the boundary conditions. Theoretical convergence is analyzed for two examples that solve scattering of plane waves incident upon air/dielectric slabs of semi-infinite and finite thicknesses. We applied the iterative algorithm for simulation of sinusoidally-perturbed dielectric slab on one side and the method converged for such unsmooth surfaces. We next simulated the shift in radiation pattern of a 6-inch dielectric lens for different offsets of the feed antenna on the focal plane. The result is compared to that of the Geometrical Optics (GO). (C) 2011 Optical Society of America

关键词： computation methods Electromagnetic scattering Geometric optics In field scattering Millimeter waves Physical optics

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Super-resolution via nonlinearity in computational optics

Super-resolution via nonlinearity in computational optics

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computational Optical Sensing and Imaging, COSI 2011

作者： Barsi, Christopher Fleischer, Jason W. Department of Electrical Engineering Princeton University Princeton NJ 08544 United States

All computational methods suffer from resolution limits due to finite-aperture effects. Using digital holography, we show that nonlinearity breaks down linear limits, as formulated by Abbe, as high-frequency spatial m... 详细信息

ISBN: (纸本)9781557529145

关键词： computation methods Digital holographic imaging Image enhancement Image metrics Image quality Visibility Digital holography (090.1995) Inverse problems (100.3190) Photorefractive optics (190.5330)

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360° reconstruction of a 3D object using cylindrical computer generated holography

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APPLIED OPTICS 2011年第34期50卷 H147-H152页

作者： Jackin, Boaz Jessie Yatagai, Toyohiko Utsunomiya Univ Ctr Opt Res & Educ Utsunomiya Tochigi 3200072 Japan

Simulated reconstruction of a three-dimensional (3D) object in 360 from cylindrical hologram is proposed. The simulation is done using a fast calculation method, where wave propagation in spectral domain and in cylindrical coordinates is used to generate the cylindrical hologram of a 3D object. The same procedure is followed to reconstruct the object back. The reconstructions resembled the original object and could be seen from all 360 degrees. The whole simulation process is done using open-source software. (C) 2011 Optical Society of America

关键词： computation methods Computer generated holograms Line scan cameras Surface waves Three dimensional reconstruction Wave propagation

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Mathematic models for a ray tracing method and its applications in wireless optical communications

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OPTICS EXPRESS 2010年第17期18卷 18431-18437页

作者： Zhang, Minglun Zhang, Yangan Yuan, Xueguang Zhang, Jinnan Beijing Univ Posts & Telecommun Minist Educ Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China

This paper presents a new ray tracing method, which contains a whole set of mathematic models, and its validity is verified by simulations. In addition, both theoretical analysis and simulation results show that the computational complexity of the method is much lower than that of previous ones. Therefore, the method can be used to rapidly calculate the impulse response of wireless optical channels for complicated systems. (C) 2010 Optical Society of America

关键词： computation methods Infrared radiation Optical wireless communication Photons Ray tracing Reflection coefficient

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Analytic-domain lens design with proximate ray tracing

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2010年第8期27卷 1791-1802页

作者： Zheng, Nan Hagen, Nathan Brady, David J. Duke Univ Dept Elect & Comp Engn Fitzpatrick Inst Photon Durham NC 27708 USA Duke Univ Dept Phys Durham NC 27708 USA

We have developed an alternative approach to optical design which operates in the analytical domain so that an optical designer works directly with rays as analytical functions of system parameters rather than as discretely sampled polylines. This is made possible by a generalization of the proximate ray tracing technique which obtains the analytical dependence of the rays at the image surface (and ray path lengths at the exit pupil) on each system parameter. The resulting method provides an alternative direction from which to approach system optimization and supplies information which is not typically available to the system designer. In addition, we have further expanded the procedure to allow asymmetric systems and arbitrary order of approximation, and have illustrated the performance of the method through three lens design examples. (C) 2010 Optical Society of America

关键词： computation methods Genetic algorithms Lens design Matrix methods Optical design software Ray tracing

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Modeling and interpretation of extinction spectra of oriented nonspherical composite particles: application to biological cells

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APPLIED OPTICS 2010年第23期49卷 4460-4471页

作者： Serebrennikova, Yulia M. Garcia-Rubio, Luis H. Claro Sci LLC St Petersburg FL 33706 USA

The majority of cells and microorganisms have a nonspherical shape and complex structure that challenge the interpretation of their spectral features. To address this issue, two approximations to the coreshell Mie theory were proposed. These included the approximation of light extinction by an ellipsoid with representation of the extinction by an equivalent sphere and representation of the extinction by a population of ellipsoidal particles with those of two weighted particle orientations. These hypotheses were first tested through numerical interpretation of the theoretical extinction spectra of prolate nucleated ellipsoids mimicking biological cells generated with anomalous diffraction approximation used as a reference method. Theoretical cases of fixed and random particle orientations demonstrated excellent capabilities of the proposed approach to retrieve the size, shape, and composition parameters of the model particles. Second, the UV-visible spectra of Leishmania species, promastigotes, elongated cells with prominent nuclei, were interpreted. The retrieved estimates of the protozoa size, shape, nucleus size, and nucleotide composition were in agreement with the corresponding microscopy estimates and literature values. Both theoretical tests and experimental results illustrated that the proposed approach can be successfully applied to estimate the structural and compositional parameters of cells from spectroscopic measurements. (C) 2010 Optical Society of America

关键词： computation methods Extinction Light scattering Mie theory Refractive index Scattering theory

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computational method for deriving the geometric point spread function of an optical system

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APPLIED OPTICS 2010年第1期49卷 126-136页

作者： Liu, Chien-Sheng Lin, Psang Dain Natl Cheng Kung Univ Dept Mech Engn Tainan 70101 Taiwan Ind Technol Res Inst Laser Applicat Technol Ctr Tainan 734 Taiwan

The distribution of the ray density of the spot diagram formed in the image plane is called the geometric point spread function (PSF). It plays an important role in the image formation theory, since it describes the impulse response of an optical system to a source point. However, the literature contains very few techniques for deriving the PSF of optical systems. Accordingly, this study presents a method based on an irradiance model for computing the geometric PSF of an optical system by considering the energy conservation along a single light ray. It is shown that the proposed method obtains a reliable and accurate estimate of the PSF and enables the computation of the centroid and root-mean-square radius of the focus spot on the image plane. In addition, compared to existing ray-counting methods presented in the literature, in which the quality of the PSF solution depends on the number of rays traced and the grid size used to mesh the image plane, the proposed irradiance-based method requires just one tracing operation. Overall, the results presented in this study confirm that the proposed method provides an ideal solution for calculating the merit function and modulation transfer function of an optical system. (C) 2009 Optical Society of America

关键词： computation methods Image formation theory Modulation transfer function Optical systems Point spread function Ray tracing

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