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Full-waveform inversion (FWI) with extended sources first computes wavefields with data-driven source extensions, such that the simulated data in inaccurate velocity models match the observed counterpart well enough to prevent cycle…

Geophysics · Physics 2023-03-03 Gaoshan Guo , Stephane Operto , Ali Gholami , Hossein S. Aghamiry

We study the impact of sampling theorems on the fidelity of sparse image reconstruction on the sphere. We discuss how a reduction in the number of samples required to represent all information content of a band-limited signal acts to…

Information Theory · Computer Science 2013-04-17 J. D. McEwen , G. Puy , J. -Ph. Thiran , P. Vandergheynst , D. Van De Ville , Y. Wiaux

In this paper, we study the problem of inferring time-varying Markov random fields (MRF), where the underlying graphical model is both sparse and changes sparsely over time. Most of the existing methods for the inference of time-varying…

Machine Learning · Computer Science 2021-02-09 Salar Fattahi , Andres Gomez

Least-squares migration can, in theory, reduce the acquisition footprint and improve the illumination of the subsurface structures. It can also recover the amplitudes of the events to some extent. However, the migration operator is not…

Geophysics · Physics 2019-02-20 Nasser Kazemi , Daniel Trad , Kris Innanen , Roman Shor

We propose a new reverse time migration method for reconstructing extended obstacles in the planar waveguide using acoustic waves at a fixed frequency. We prove the resolution of the reconstruction method in terms of the aperture and the…

Classical Physics · Physics 2015-10-28 Zhiming Chen , Guanghui Huang

We study the problem of reconstructing an image from information stored at contour locations. We show that high-quality reconstructions with high fidelity to the source image can be obtained from sparse input, e.g., comprising less than…

Computer Vision and Pattern Recognition · Computer Science 2018-04-11 Tali Dekel , Chuang Gan , Dilip Krishnan , Ce Liu , William T. Freeman

Reconstruction of images from noisy linear measurements is a core problem in image processing, for which convex optimization methods based on total variation (TV) minimization have been the long-standing state-of-the-art. We present an…

Information Theory · Computer Science 2016-08-31 Jean Barbier , Eric W. Tramel , Florent Krzakala

Consider the problem of inverse scattering of time-harmonic point sources from an infinite, penetrable rough interface with bounded obstacles buried in the lower half-space, where the interface is assumed to be a local perturbation of a…

Analysis of PDEs · Mathematics 2020-09-02 Jianliang Li , Jiaqing Yang , Bo Zhang

Spectral image reconstruction is an important task in snapshot compressed imaging. This paper aims to propose a new end-to-end framework with iterative capabilities similar to a deep unfolding network to improve reconstruction accuracy,…

Image and Video Processing · Electrical Eng. & Systems 2023-05-09 Zeyu Cai , Jian Yu , Ziyu Zhang , Chengqian Jin , Feipeng Da

The dose of X-ray radiation and the scanning time are crucial factors in computed tomography (CT) for clinical applications. In this work, we introduce a multi-source static CT imaging system designed to rapidly acquire sparse view and…

Medical Physics · Physics 2025-01-03 Ziju Shen , Haimiao Zhang , Bin Dong , Jun Qiu , Yunxiang Li , Zhili Cui

We address the curse of dimensionality in dynamic covariance estimation by modeling the underlying co-volatility dynamics of a time series vector through latent time-varying stochastic factors. The use of a global-local shrinkage prior for…

Methodology · Statistics 2019-08-07 Gregor Kastner

This paper addresses the solution of inverse problems in imaging given an additional reference image. We combine a modification of the discrete geodesic path model for image metamorphosis with a variational model,actually the $L^2$-$TV$…

Numerical Analysis · Mathematics 2019-05-22 Sebastian Neumayer , Johannes Persch , Gabriele Steidl

We consider the resolution of the single frequency reverse time migration (RTM) method for extended targets without the assumption of the validation of geometric optics approximation. The resolution analysis, which applies in both…

Mathematical Physics · Physics 2014-06-11 Junqing Chen , Zhiming Chen , Guanghui Huang

Motivated by the need for efficient estimation of conditional expectations, we consider a least-squares function approximation problem with heavily polluted data. Existing methods that are effective in the small-noise regime are suboptimal…

Machine Learning · Statistics 2026-05-26 Ben Adcock , Bernhard Hientzsch , Akil Narayan , Yiming Xu

A space-time interface-fitted approximation of an inverse source problem for the advection-diffusion equation with moving subdomains is investigated. The problem is reformulated as an optimization problem using Tikhonov regularization. A…

Numerical Analysis · Mathematics 2025-02-11 Thi Thanh Mai Ta , Quang Huy Nguyen , Dinh Nho Hào

We study the real-time dynamics retrieval from a time series via the time-frequency (TF) analysis with the minimal latency guarantee. While different from the well-known intrinsic latency definition in the filter design, a rigorous…

Multimedia · Computer Science 2016-06-30 Li Su , Hau-tieng Wu

How can we compute the pseudoinverse of a sparse feature matrix efficiently and accurately for solving optimization problems? A pseudoinverse is a generalization of a matrix inverse, which has been extensively utilized as a fundamental…

Machine Learning · Computer Science 2020-11-10 Jinhong Jung , Lee Sael

Time-of-Flight (ToF) depth sensing camera is able to obtain depth maps at a high frame rate. However, its low resolution and sensitivity to the noise are always a concern. A popular solution is upsampling the obtained noisy low resolution…

Computer Vision and Pattern Recognition · Computer Science 2015-06-18 Wei Liu , Yijun Li , Xiaogang Chen , Jie Yang , Qiang Wu , Jingyi Yu

This paper addresses the problem of sparse phase retrieval, a fundamental inverse problem in applied mathematics, physics, and engineering, where a signal need to be reconstructed using only the magnitude of its transformation while phase…

Machine Learning · Statistics 2025-04-15 The Tien Mai

In recent years, computational Time-of-Flight (ToF) imaging has emerged as an exciting and a novel imaging modality that offers new and powerful interpretations of natural scenes, with applications extending to 3D, light-in-flight, and…

Image and Video Processing · Electrical Eng. & Systems 2024-11-05 Ruiming Guo , Ayush Bhandari