We describe a method of measuring the four paraxial lens parameters-the two radii, the center thickness, and the index-of a realistic-size positive lens using an autostigmatic microscope (ASM). The method is similar t...
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We describe a method of measuring the four paraxial lens parameters-the two radii, the center thickness, and the index-of a realistic-size positive lens using an autostigmatic microscope (ASM). The method is similar to measuring the radius of curvature of a concave mirror with an ASM but slightly more complex in that four characteristic distances must be measured to solve for the four unknown parameters. Once the four distances are measured, it is shown how to use an Excel spreadsheet and the add-in iterative "Solver" to find the four unknown parameters. Finding the paraxial lens parameters is useful for troubleshooting a lens assembly that does not perform as expected due to mislabeling, the incorrect glass type used, insertion into the assembly backward, or for finding a replacement glass type. (C) 2015 Optical Society of America
Ray tracing is a powerful technique to understand the light behavior through an intricate optical system such as that of a human eye. The prediction of visual acuity can be achieved through characteristics of an optic...
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Ray tracing is a powerful technique to understand the light behavior through an intricate optical system such as that of a human eye. The prediction of visual acuity can be achieved through characteristics of an optical system such as the geometrical point spread function. In general, its precision depends on the number of discrete rays and the accurate surface representation of each eye's components. Recently, a method that simplifies calculation of the geometrical point spread function has been proposed for circularly symmetric systems [Appl. Opt. 53, 4784 (2014)]. An extension of this method to 2D noncircularly symmetric systems is proposed. In this method, a two-dimensional ray tracing procedure for an arbitrary number of surfaces and arbitrary surface shapes has been developed where surfaces, rays, and refractive indices are all represented in functional forms being approximated by Chebyshev polynomials. The Liou and Brennan anatomically accurate eye model has been adapted and used for evaluating the method. Further, real measurements of the anterior corneal surface of normal, astigmatic, and keratoconic eyes were substituted for the first surface in the model. The results have shown that performing ray tracing, utilizing the two-dimensional Chebyshev function approximation, is possible for noncircularly symmetric models, and that such calculation can be performed with a newly created Chebfun toolbox. (C) 2015 Optical Society of America
Acoustic multiple scattering by a cluster of cylinders in an acoustic medium is considered. A fast recursive technique is described which takes advantage of the multilevel Block Toeplitz structure of the linear system...
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Acoustic multiple scattering by a cluster of cylinders in an acoustic medium is considered. A fast recursive technique is described which takes advantage of the multilevel Block Toeplitz structure of the linear system. A parallelization technique is described that enables efficient application of the proposed recursive algorithm for solving multilevel Block Toeplitz systems on high performance computer clusters. Numerical comparisons of CPU time and total elapsed time taken to solve the linear system using the direct LAPACK and TOEPLITZ libraries on Intel FORTRAN, show the advantage of the TOEPLITZ solver. computations are optimized by multi-threading which displays improved efficiency of the TOEPLITZ solver with the increase of the number of scatterers and frequency. (C) 2015 Elsevier Inc. All rights reserved.
This paper presents a massively parallel method for the phase reconstruction of an object from its bispectrum phase. Our aim is to recover an enhanced version of a turbulence-corrupted image by developing an efficient...
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This paper presents a massively parallel method for the phase reconstruction of an object from its bispectrum phase. Our aim is to recover an enhanced version of a turbulence-corrupted image by developing an efficient and fast parallel image-restoration algorithm. The proposed massively parallel bispectrum algorithm relies on multiple block parallelization. Further, in each block, we employ wavefront processing through strength reduction to parallelize an iterative algorithm. Results are presented and compared with the existing iterative bispectrum method. We report a speed-up factor of 85.94 with respect to sequential implementation of the same algorithm for an image size of 1024 x 1024. (C) 2015 Optical Society of America
This paper has proposed and illustrated two fast methods of computing antenna factor (AF) of a compact wideband antenna (CWA), which is designed to measure the electromagnetic environment inside spacecraft cabin. The ...
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ISBN:
(纸本)9781467394451
This paper has proposed and illustrated two fast methods of computing antenna factor (AF) of a compact wideband antenna (CWA), which is designed to measure the electromagnetic environment inside spacecraft cabin. The computational results show good agreement with the experimental ones.
A modification of the Monte-Carlo ray tracing procedure for axisymmetric surfaces is proposed. The main idea consists in the approximation of optical surfaces by truncated cones and the use of an unconventional k-d tr...
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A modification of the Monte-Carlo ray tracing procedure for axisymmetric surfaces is proposed. The main idea consists in the approximation of optical surfaces by truncated cones and the use of an unconventional k-d tree. The simulation results show high performance of the proposed method, with the ray tracing procedure working 3-12 times faster than conventional algorithms based on a triangle approximation.
Optical tweezers have found widespread application in many fields, from physics to biology. Here, we explain in detail how optical forces and torques can be described within the geometrical optics approximation, and w...
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Optical tweezers have found widespread application in many fields, from physics to biology. Here, we explain in detail how optical forces and torques can be described within the geometrical optics approximation, and we show that this approximation provides reliable results in agreement with experiments for particles whose characteristic dimensions are larger than the wavelength of the trapping light. Furthermore, we provide an object-oriented software package implemented in MATLAB for the calculation of optical forces and torques in the geometrical optics regime: Optical Tweezers in Geometrical Optics (OTGO). We provide all source codes for OTGO as well as documentation and code examples-e.g., standard optical tweezers, optical tweezers with elongated particles, the windmill effect, and Kramers transitions between two optical traps-necessary to enable users to effectively employ it in their research. (C) 2015 Optical Society of America
Previous research [Appl. Opt. 52, A290 (2013)] has revealed that Fourier analysis of three-dimensional affine transformation theory can be used to improve the computation speed of the traditional polygonbased method. ...
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Previous research [Appl. Opt. 52, A290 (2013)] has revealed that Fourier analysis of three-dimensional affine transformation theory can be used to improve the computation speed of the traditional polygonbased method. In this paper, we continue our research and propose an improved full analytical polygonbased method developed upon this theory. Vertex vectors of primitive and arbitrary triangles and the pseudo-inverse matrix were used to obtain an affine transformation matrix representing the spatial relationship between the two triangles. With this relationship and the primitive spectrum, we analytically obtained the spectrum of the arbitrary triangle. This algorithm discards low-level angular dependent computations. In order to add diffusive reflection to each arbitrary surface, we also propose a whole matrix computation approach that takes advantage of the affine transformation matrix and uses matrix multiplication to calculate shifting parameters of similar sub-polygons. The proposed method improves hologram computation speed for the conventional full analytical approach. Optical experimental results are demonstrated which prove that the proposed method can effectively reconstruct three-dimensional scenes. (c) 2014 Optical Society of America
We present a wide-field microscopy technique for the 3D mapping of optical intensity distributions using Brownian gold nanoparticles as local probes, which are localized by off-axis holography. Fast computation method...
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We present a wide-field microscopy technique for the 3D mapping of optical intensity distributions using Brownian gold nanoparticles as local probes, which are localized by off-axis holography. Fast computation methods allow us to localize hundreds of particles per minute with accuracies as good as 3 x 3 x 10nm(3) for immobilized particles. Factors limiting this accuracy are discussed and the possibilities of the technique are illustrated through the 3D optical mapping of an evanescent and a propagative wave. Our results pave the way for a new stochastic imaging technique, well adapted to subwavelength optical characterization in water-based systems. (C) 2014 Optical Society of America
This paper has proposed and illustrated two fast methods of computing antenna factor(AF) of a compact wideband antenna(CWA),which is designed to measure the electromagnetic environment inside spacecraft *** computatio...
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This paper has proposed and illustrated two fast methods of computing antenna factor(AF) of a compact wideband antenna(CWA),which is designed to measure the electromagnetic environment inside spacecraft *** computational results show good agreement with the experimental ones.
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