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Related papers: Decomposition of Optical Flow on the Sphere

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Turbulence organization, long conceptualized in terms of spatial coherent-structures, has resisted clear description. A major limitation has been the lack of tools to identify instantaneous spatial organization, while unravelling the…

Fluid Dynamics · Physics 2024-06-19 Siddhartha Mukherjee , Merlijn Mascini , Luis M. Portela

Real-space refinement of atomic models in macromolecular crystallography or in cryo electron microscopy fits a model to a map obtained experimentally. This requires generating model maps of a limited resolution which moreover may vary from…

Computational Engineering, Finance, and Science · Computer Science 2022-06-22 Ludmila Urzhumtseva , Vladimir Y. Lunin , Alexandre Urzhumtsev

A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields. In this context, we present…

Astrophysics · Physics 2007-05-23 M. Gillon , P. Magain , V. Chantry , G. Letawe , S. Sohy , F. Courbin , F. Pont , C. Moutou

Normalizing flows have shown great promise for modelling flexible probability distributions in a computationally tractable way. However, whilst data is often naturally described on Riemannian manifolds such as spheres, torii, and hyperbolic…

Machine Learning · Statistics 2020-12-10 Emile Mathieu , Maximilian Nickel

We propose to incorporate feature correlation and sequential processing into dense optical flow estimation from event cameras. Modern frame-based optical flow methods heavily rely on matching costs computed from feature correlation. In…

Computer Vision and Pattern Recognition · Computer Science 2021-10-22 Mathias Gehrig , Mario Millhäusler , Daniel Gehrig , Davide Scaramuzza

Some metrological means, such as Shack-Hartmann, deflectometry sensors or fringe projection profilometry, measure the shape of an optical surface indirectly from slope measurements. Zonal shape reconstruction, a method to reconstruct shape…

The notion of inertial reference frame is abandoned and I replaced it by a local reference frame on which the fundamental law of mechanics is expressed. The distant interactions of cause and effect are modeled by the propagation of waves…

Fluid Dynamics · Physics 2020-08-10 Jean-Paul Caltagirone

This work advocates Eulerian motion representation learning over the current standard Lagrangian optical flow model. Eulerian motion is well captured by using phase, as obtained by decomposing the image through a complex-steerable pyramid.…

Computer Vision and Pattern Recognition · Computer Science 2016-09-09 S. L. Pintea , J. C. van Gemert

Recent advances in cross-modal few-shot adaptation treat visual-semantic alignment as a continuous feature transport problem via Flow Matching (FM). However, we argue that Euclidean-based FM overlooks fundamental limitations of flat…

Computer Vision and Pattern Recognition · Computer Science 2026-02-25 Lin Li , Ziqi Jiang , Gefan Ye , Zhenqi He , Jiahui Li , Jun Xiao , Kwang-Ting Cheng , Long Chen

The aim of this paper is to establish a nonlinear variational approach to the reconstruction of moving density images from indirect dynamic measurements. Our approach is to model the dynamics as a hyperelastic deformation of an initial…

Numerical Analysis · Mathematics 2015-12-01 Martin Burger , Jan Modersitzki , Sebastian Suhr

Astrophysical turbulent flows display an intrinsically multi-scale nature, making their numerical simulation and the subsequent analyses of simulated data a complex problem. In particular, two fundamental steps in the study of turbulent…

Instrumentation and Methods for Astrophysics · Physics 2024-07-10 David Vallés-Pérez , Susana Planelles , Vicent Quilis , Frederick Groth , Tirso Marin-Gilabert , Klaus Dolag

We present a multipole expansion theory for optical force exerting on a particle immersed in generic monochromatic free-space optical field. Based on the theory, we have, for the first time, successfully decomposed the optical force on a…

Optics · Physics 2018-01-01 Yikun Jiang , Jun Chen , Jack Ng , Zhifang Lin

Conley indices and Morse decompositions of flows can be found by using algorithms which rigorously analyze discrete dynamical systems. This usually involves integrating a time discretization of the flow using interval arithmetic. We compare…

Dynamical Systems · Mathematics 2015-11-16 Konstantin Mischaikow , Marian Mrozek , Frank Weilandt

Three-dimensional (3D) biomedical image sets are often acquired with in-plane pixel spacings that are far less than the out-of-plane spacings between images. The resultant anisotropy, which can be detrimental in many applications, can be…

Computer Vision and Pattern Recognition · Computer Science 2018-12-24 Berkay Kanberoglu , Dhritiman Das , Priya Nair , Pavan Turaga , David Frakes

The wave equation for vectors and symmetric tensors in spherical coordinates is studied under the divergence-free constraint. We describe a numerical method, based on the spectral decomposition of vector/tensor components onto spherical…

General Relativity and Quantum Cosmology · Physics 2009-11-23 Jerome Novak , Jean-Louis Cornou , Nicolas Vasset

We formulate a method for computing Stokes flow past a highly deformed sphere with arbitrarily defined surface velocity. The fundamental ingredient is an explicit extrapolation operator extending a velocity field from the surface of a…

Soft Condensed Matter · Physics 2018-01-25 Amir Nourhani , Paul E. Lammert

Unsupervised optical flow methods typically lack reliable uncertainty estimation, limiting their robustness and interpretability. We propose U$^{2}$Flow, the first recurrent unsupervised framework that jointly estimates optical flow and…

Computer Vision and Pattern Recognition · Computer Science 2026-04-14 Xunpei Sun , Wenwei Lin , Yi Chang , Gang Chen

This paper is devoted to numerical approximations for the wave equation with a multiscale character. Our approach is formulated in the framework of the Localized Orthogonal Decomposition (LOD) interpreted as a numerical homogenization with…

Numerical Analysis · Mathematics 2015-09-23 Assyr Abdulle , Patrick Henning

Real-time motion detection in non-stationary scenes is a difficult task due to dynamic background, changing foreground appearance and limited computational resource. These challenges degrade the performance of the existing methods in…

Computer Vision and Pattern Recognition · Computer Science 2018-11-22 Junjie Huang , Wei Zou , Zheng Zhu , Jiagang Zhu

The stationary velocity field (SVF) approach allows to build parametrizations of invertible deformation fields, which is often a desirable property in image registration. Its expressiveness is particularly attractive when used as a block…

Computer Vision and Pattern Recognition · Computer Science 2024-10-16 Johannes Bostelmann , Ole Gildemeister , Jan Lellmann