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Wave front sensing of the surface of equal phase for a propagating electromagnetic wave is a vital technology in fields ranging from real time adaptive optics, to high accuracy metrology, to medical optometry. We have developed a new method…

Optics · Physics 2025-10-01 C. L. Carilli , L. Torino , B. Nikolic , N. Thyagarajan , U. Iriso

Phase retrieval (PR) is a crucial problem in many imaging applications. This study focuses on resolving the holographic phase retrieval problem in situations where the measurements are affected by a combination of Poisson and Gaussian…

Signal Processing · Electrical Eng. & Systems 2023-09-22 Zongyu Li , Jason Hu , Xiaojian Xu , Liyue Shen , Jeffrey A. Fessler

Seismic inversion is a core problem in geophysical exploration, where traditional methods suffer from high computational costs and are susceptible to initial model dependence. In recent years, deep generative model-based seismic inversion…

Machine Learning · Computer Science 2026-03-17 Haofei Xu , Wei Cheng , Sizhe Li , Jie Xiong

We present GRaF, Generalizable Radio-Frequency (RF) Radiance Fields, a framework that models RF signal propagation to synthesize spatial spectra at arbitrary transmitter or receiver locations, where each spectrum measures signal power…

Networking and Internet Architecture · Computer Science 2026-04-21 Kang Yang , Yuning Chen , Wan Du

Radar target detection in the presence of a mixture of non-Gaussian clutter and white thermal noise is a challenging problem. This paper proposes a Rectified Flow Matching-based method for radar detection, termed D-RFM. Unlike existing…

Signal Processing · Electrical Eng. & Systems 2026-03-20 P. Meena , Y. A. Rouzoumka , J. Pinsolle , C. Ren , M. N. El Korso , J. -P. Ovarlez

The stepped-frequency (SF) waveform is an effective way to achieve high range resolution (HRR) in modern radars. In this paper, we determine some fundamental limits of SF waveforms on ambiguity, stability and accuracy of stable targets…

Information Theory · Computer Science 2018-08-29 Yimin Liu , Xiqin Wang , Tianyao Huang

An important application of next-generation wide-field radio interferometers is making high dynamic range maps of radio emission. Traditional deconvolution methods like CLEAN can give poor recovery of diffuse structure, prompting the…

Instrumentation and Methods for Astrophysics · Physics 2024-10-23 Katrine A. Glasscock , Philip Bull , Jacob Burba , Hugh Garsden , Michael J. Wilensky

Modern image formation algorithms in radio interferometry rely on repeated applications of the operator {\Phi} modelling the measurement process and its adjoint {Phi^\dagger} to enforce consistency with the acquired data, specifically via…

Instrumentation and Methods for Astrophysics · Physics 2026-05-27 Arwa Dabbech , Yves Wiaux

Full-waveform inversion (FWI) is a powerful technique for reconstructing high-resolution material parameters from seismic or ultrasound data. The conventional least-squares (\(L^{2}\)) misfit suffers from pronounced non-convexity that leads…

Optimization and Control · Mathematics 2025-08-26 Matej Neumann , Yunan Yang

We report for the first time a method-independent geometrical expression for the angular resolution of an arbitrary network of interferometric gravitational wave (GW) detectors when the arrival-time of a GW is unknown. We discuss the…

General Relativity and Quantum Cosmology · Physics 2009-11-13 Linqing Wen , Xilong Fan , Yanbei Chen

In this lecture, we describe a number of advanced gain calibration techniques. In particular, self-calibration is an important tool in interferometric imaging at all wavelengths. It allows the observer to determine and remove residual phase…

Instrumentation and Methods for Astrophysics · Physics 2018-05-15 Crystal L. Brogan , Todd R. Hunter , Ed B. Fomalont

Full Waveform Inversion (FWI) is a successful and well-established inverse method for reconstructing material models from measured wave signals. In the field of seismic exploration, FWI has proven particularly successful in the…

Computational Engineering, Finance, and Science · Computer Science 2023-12-05 Tim Bürchner , Philipp Kopp , Stefan Kollmannsberger , Ernst Rank

In ground-based astronomy, Adaptive Optics (AO) is a pivotal technique, engineered to correct wavefront phase distortions and thereby enhance the quality of the observed images. Integral to an AO system is the wavefront sensor (WFS), which…

Instrumentation and Methods for Astrophysics · Physics 2026-05-07 Yutong Wu , Roland Wagner , Ronny Ramlau , Raymond H. Chan

Seismic full waveform inversion (FWI) is a powerful technique to generate high resolution images of the Earth's interior. However, significant uncertainty exists in all FWI solutions due to imperfect acquisition geometries, inherent noise…

Geophysics · Physics 2026-03-13 Xuebin Zhao , Andrew Curtis

Variational inference, such as the mean-field (MF) approximation, requires certain conjugacy structures for efficient computation. These can impose unnecessary restrictions on the viable prior distribution family and further constraints on…

Statistics Theory · Mathematics 2023-09-11 Rentian Yao , Yun Yang

Flow Matching has become a cornerstone of modern generative models like Stable Diffusion 3, largely due to the efficiency of its Rectified Flow (RF) variant. The success of RF hinges on iteratively learning straight trajectories, pushing…

Machine Learning · Computer Science 2026-05-19 Vansh Bansal , Saptarshi Roy , Purnamrita Sarkar , Alessandro Rinaldo

Conventional optical coherent receivers capture the full electrical field, including amplitude and phase, of a signal waveform by measuring its interference against a stable continuous-wave local oscillator (LO). In optical coherent…

Signal Processing · Electrical Eng. & Systems 2020-06-24 Haoshuo Chen , Nicolas K. Fontaine , Joan M. Gene , Roland Ryf , David T. Neilson , Gregory Raybon

Diffraction tomography aims to recover an object's scattering potential from measured wave fields. In the classical setting, the object is illuminated by plane waves from many directions, and the Fourier diffraction theorem provides a…

Numerical Analysis · Mathematics 2026-03-11 Peter Elbau , Noemi Naujoks

Full Waveform Inversion (FWI) is a highly nonlinear and ill-posed problem that aims to recover subsurface velocity maps from surface-recorded seismic waveforms data. Existing data-driven FWI typically uses small models, as available…

Machine Learning · Computer Science 2026-05-29 Yinan Feng , Peng Jin , Yuzhe Guo , Yinpeng Chen , Youzuo Lin

Most methods tackling the phase retrieval problem of magnitude-only antenna measurements suffer from unrealistic sampling requirements, from unfeasible computational complexities, and, most severely, from the lacking reliability of…

Signal Processing · Electrical Eng. & Systems 2022-02-01 Alexander Paulus , Josef Knapp , Jonas Kornprobst , Thomas F. Eibert