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In the last five decades, iterative phase retrieval methods draw large amount of interest across the research community as a non-interferometric approach to recover quantitative phase distributions from one (or more) intensity measurement.…

Optics · Physics 2020-07-21 Nathaniel Hai , Joseph Rosen

We propose a data-driven algorithm for reconstructing the irregular, chaotic flow dynamics around two side-by-side square cylinders from sparse, time-resolved, velocity measurements in the wake. We use Proper Orthogonal Decomposition (POD)…

Fluid Dynamics · Physics 2022-09-08 Flavio Savarino , George Papadakis

We introduce a higher order phase averaging method for nonlinear oscillatory systems. Phase averaging is a technique to filter fast motions from the dynamics whilst still accounting for their effect on the slow dynamics. Phase averaging is…

Dynamical Systems · Mathematics 2022-03-09 Werner Bauer , Colin J. Cotter , Beth Wingate

The estimation of phase errors from digital-holography data is critical for applications such as imaging or wave-front sensing. Conventional techniques require multiple i.i.d. data and perform poorly in the presence of high noise or large…

Data Analysis, Statistics and Probability · Physics 2017-10-11 Casey J. Pellizzari , Mark F. Spencer , Charles A. Bouman

We propose Flow Mismatching, an unsupervised anomaly detection method that deliberately avoids reconstruction-based paradigms. Instead, we treat flow matching as geometric dynamics and leverage a key insight: anomalies occur at places where…

Computer Vision and Pattern Recognition · Computer Science 2026-05-25 Shengzhe Chen , Mehrdad Moradi , Kamran Paynabar , Hao Yan

In this work we propose a one-class self-supervised method for anomaly segmentation in images that benefits both from a modern machine learning approach and a more classic statistical detection theory. The method consists of four phases.…

Computer Vision and Pattern Recognition · Computer Science 2024-06-04 Matías Tailanian , Álvaro Pardo , Pablo Musé

In recent years, consumer-level depth cameras have been adopted for various applications. However, they often produce depth maps at only a moderately high frame rate (approximately 30 frames per second), preventing them from being used for…

Graphics · Computer Science 2018-11-06 Ming-Ze Yuan , Lin Gao , Hongbo Fu , Shihong Xia

This paper introduces a new algorithm to improve the accuracy of numerical phase-averaging in oscillatory, multiscale, differential equations. Phase-averaging is a timestepping method which averages a mapped variable to remove highly…

Numerical Analysis · Mathematics 2024-11-07 Timothy C. Andrews , Beth A. Wingate

The propagation of light through a turbulent flow field around an aircraft results in optical distortions commonly known as aero-optic effects. The development of methods to mitigate these effects requires large amounts of realistic…

Signal Processing · Electrical Eng. & Systems 2026-05-08 Jeffrey W. Utley , Gregery T. Buzzard , Charles A. Bouman , Matthew R. Kemnetz

In this paper we consider the nonlinear inverse problem of phase retrieval in the context of dynamical sampling. Where phase retrieval deals with the recovery of signals & images from phaseless measurements, dynamical sampling was…

Numerical Analysis · Mathematics 2021-02-02 Robert Beinert , Marzieh Hasannasab

Event cameras such as DAVIS can simultaneously output high temporal resolution events and low frame-rate intensity images, which own great potential in capturing scene motion, such as optical flow estimation. Most of the existing optical…

Computer Vision and Pattern Recognition · Computer Science 2022-11-18 Zhexiong Wan , Yuchao Dai , Yuxin Mao

The framework of normalizing flows provides a general strategy for flexible variational inference of posteriors over latent variables. We propose a new type of normalizing flow, inverse autoregressive flow (IAF), that, in contrast to…

Machine Learning · Computer Science 2017-02-01 Diederik P. Kingma , Tim Salimans , Rafal Jozefowicz , Xi Chen , Ilya Sutskever , Max Welling

Phase imaging techniques extract the optical path-length information of a scene, whereas wavefront sensors provide the shape of an optical wavefront. Since these two applications have different technical requirements, they have developed…

Optics · Physics 2018-02-28 F. Soldevila , V. Durán , P. Clemente , J. Lancis , E. Tajahuerce

Many problems in the geophysical sciences demand the ability to calibrate the parameters and predict the time evolution of complex dynamical models using sequentially-collected data. Here we introduce a general methodology for the joint…

Computation · Statistics 2018-12-12 Sara Pérez-Vieites , Inés P. Mariño , Joaquín Míguez

Each training step for a variational autoencoder (VAE) requires us to sample from the approximate posterior, so we usually choose simple (e.g. factorised) approximate posteriors in which sampling is an efficient computation that fully…

Machine Learning · Statistics 2018-05-29 Laurence Aitchison , Vincent Adam , Srinivas C. Turaga

Fourier Ptychography is a recently proposed imaging technique that yields high-resolution images by computationally transcending the diffraction blur of an optical system. At the crux of this method is the phase retrieval algorithm, which…

Computer Vision and Pattern Recognition · Computer Science 2018-05-10 Lokesh Boominathan , Mayug Maniparambil , Honey Gupta , Rahul Baburajan , Kaushik Mitra

Wave-front sensing from focal plane multiple images is a promising technique for high-contrast imaging systems. However, the wave-front error of an optics system can be properly reconstructed only when it is very small. This paper presents…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Jiangpei Dou , Deqing Ren , Yongtian Zhu

Iterative phase retrieval algorithms are widely used in digital optics for their efficiency and simplicity. Conventionally, these algorithms do not consider aberrations as they assume an ideal, aberration-free optical system. Here, we…

Optics · Physics 2025-02-10 Dylan Brault , Corinne Fournier , Tatiana Latychevskaia

Phase retrieval in dynamical sampling is a novel research direction, where an unknown signal has to be recovered from the phaseless measurements with respect to a dynamical frame, i.e. a sequence of sampling vectors constructed by the…

Numerical Analysis · Mathematics 2021-03-19 Robert Beinert , Marzieh Hasannasab

We introduce a temporal scheme for data sampling, based on a variable delay between two successive data acquisitions. The scheme is designed so as to reduce the average data flow rate, while still retaining the information on the data…

Soft Condensed Matter · Physics 2016-08-06 A. Philippe , S. Aime , V. Roger , R. Jelinek , G. Prévot , L. Berthier , L. Cipelletti
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