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Capturing screens is now routine in our everyday lives. But the photographs of emissive displays are often influenced by the flicker-banding (FB), which is alternating bright%u2013dark stripes that arise from temporal aliasing between a…

Computer Vision and Pattern Recognition · Computer Science 2025-10-20 Libo Zhu , Zihan Zhou , Xiaoyang Liu , Weihang Zhang , Keyu Shi , Yifan Fu , Yulun Zhang

All optical systems, which involve the collimation of a reflected, transmitted or scattered wave subsequent to tight focusing, are subject to two kinds of deviations. One is the wavefront curvature due to inaccurate focal placement of the…

Optics · Physics 2024-06-10 Nitish Kumar , Anirban Debnath , Nirmal K. Viswanathan

Face forgery has attracted increasing attention in recent applications of computer vision. Existing detection techniques using the two-branch framework benefit a lot from a frequency perspective, yet are restricted by their fixed frequency…

Computer Vision and Pattern Recognition · Computer Science 2022-03-29 Neng Wang , Yang Bai , Kun Yu , Yong Jiang , Shu-tao Xia , Yan Wang

This paper addresses the problem of frequency-domain inter-carrier interference (ICI) mitigation for differential orthogonal frequency-division multiplexing (OFDM) systems. The classical fractional fast Fourier transform (F-FFT), adopting…

Information Theory · Computer Science 2021-10-12 Jihui Qiu , Yuzhou Li , Yunlong Huang , Yimeng Wang , Lingyu Gu

Context. Narrow-band interference filters can be tuned toward shorter wavelengths by tilting them from the perpendicular to the optical axis. This can be used as a cheap alternative to real tunable filters, such as Fabry-P\'erot…

Instrumentation and Methods for Astrophysics · Physics 2011-08-31 Mats G. Löfdahl , Vasco M. J. Henriques , Dan Kiselman

This dissertation is concerned with understanding and analyzing some of the effects of diffraction in the near field. The contributions of homogeneous and of evanescent waves to two-dimensional near-field diffraction patterns of scalar…

Optics · Physics 2007-05-23 Marek W. Kowarz

We report on an experimental measurement of the pulse front tilt (PFT) of spatiotemporally focused femtosecond laser pulses in the focal plane in both air and bulk transparent materials, which is achieved by examination of the interference…

The measurement of extremely small displacements is of utmost importance, both for fundamental studies [1-4], and practical applications [5-7]. One way to estimate a small displacement is to measure the Doppler shift generated in light…

Instrumentation and Detectors · Physics 2019-01-30 Bethany J. Little , Julián Martínez-Rincón , Umberto Bortolozzo , Stefania Residori , John C. Howell

The Fast Fourier Transform (FFT) is a numerical operation that transforms a function into a form comprised of its constituent frequencies and is an integral part of scientific computation and data analysis. The objective of our work is to…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-02-04 Sudhanshu Kulkarni , Burlen Loring , E. Wes Bethel

FFT-based solvers introduced in the 1990s for the numerical homogenization of heterogeneous elastic materials have been extended to a wide range of physical properties. In parallel, alternative algorithms and modified discrete Green…

Materials Science · Physics 2015-05-20 Lionel Gélébart , Franck Ouaki

The use of one or more gold nanoballs as reference objects for Fourier Transform holography (FTH) is analysed using experimental soft X-ray diffraction from objects consisting of separated clusters of these balls. The holograms are…

Spectra derived from fast Fourier transform (FFT) analysis of time-domain data intrinsically contain statistical fluctuations whose distribution depends on the number of accumulated spectra contributing to a measurement. The tail of this…

Solar and Stellar Astrophysics · Physics 2015-06-19 Gelu M. Nita , Gregory D. Fleishman , Dale E. Gary , William Marin , Kristine Boone

To comprehensively assess optical fiber communication system conditions, it is essential to implement joint estimation of the following four critical impairments: nonlinear signal-to-noise ratio (SNRNL), optical signal-to-noise ratio…

Signal Processing · Electrical Eng. & Systems 2023-08-29 Ting Jiang , Zheng Gao , Yizhao Chen , Zihe Hu , Ming Tang

We employ electrostatic conversion drift calculations to match CCD pixel signal covariances observed in flat field exposures acquired using candidate sensor devices for the LSST Camera. We thus constrain pixel geometry distortions present…

A simple analytic method of estimating the error involved in using an approximate boundary condition for diffuse radiation in two adjoining scattering media with differing refractive index is presented. The method is based on asymptotic…

Optics · Physics 2015-05-28 Adrian C. Selden

As opposed to metasurfaces, metagratings represent themselves sparse arrangements of scatterers. Established rigorous analytical models allow metagratings to overcome performance of metasurfaces in beam steering applications while handling…

Applied Physics · Physics 2020-04-22 Vladislav Popov , Fabrice Boust , Shah Nawaz Burokur

Fresnel zone plates are diffractive elements that are essential to form images in many scientific and technological areas, especially where refractive optics is not available. One of the main shortcomings of Fresnel zone plates, which limit…

Optics · Physics 2007-05-23 Walter D. Furlan , Genaro Saavedra , Juan A. Monsoriu

As has been known, the Nyquist first condition promises no intersymbol interference (ISI) as derived in the frequency domain. However, the practical implementation using the FIR filter truncates the Fourier transform by its window and…

Signal Processing · Electrical Eng. & Systems 2024-02-08 Zijian Zhou , Lifeng Lin , Bingli Jiao

The enhanced-NA Fresnel hologram reconstructs a holographic image at a viewing angle larger than the diffraction angle of a hologram pixel. The image space is limited by the bandwidth of a digital hologram. In this study, we investigate the…

Optics · Physics 2022-06-28 Byung Gyu Chae

Atomic diffusion at nanometer length scale may differ significantly from bulk diffusion, and may sometimes even exhibit counterintuitive behavior. In the present work, taking Cu/Ni as a model system, a general phenomenon is reported which…

Materials Science · Physics 2019-05-15 Atul Tiwari , M. K. Tiwari , Mukul Gupta , H. -C. Wille , Ajay Gupta
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