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Phase-retrieval from coded diffraction patterns (CDP) is important to X-ray crystallography, diffraction tomography and astronomical imaging, yet remains a hard, non-convex inverse problem. We show that CDP recovery can be reformulated…

In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a…

Optical phased arrays (OPAs) which beam-steer in 2D have so far been unable to pack emitting elements at $\lambda/2$ spacing, leading to grating lobes which limit the field-of-view, introduce signal ambiguity, and reduce optical efficiency.…

Applied Physics · Physics 2020-08-25 Nathan Dostart , Bohan Zhang , Michael Brand , Daniel Feldkhun , Miloš Popović , Kelvin Wagner

We consider a popular nonsmooth formulation of the real phase retrieval problem. We show that under standard statistical assumptions, a simple subgradient method converges linearly when initialized within a constant relative distance of an…

Optimization and Control · Mathematics 2018-01-09 Damek Davis , Dmitriy Drusvyatskiy , Courtney Paquette

We describe a new algorithm to solve a particular phase retrieval problem, that has wide applications in audio processing: the reconstruction of a function from its scalogram, that is from the modulus of its wavelet transform. It is a…

Optimization and Control · Mathematics 2017-04-11 Irène Waldspurger

Compressed sensing is a signal processing scheme that reconstructs high-dimensional sparse signals from a limited number of observations. In recent years, various problems involving signals with a finite number of discrete values have been…

Statistical Mechanics · Physics 2024-08-20 Mikiya Doi , Masayuki Ohzeki

The one-dimensional phase retrieval problem consists in the recovery of a complex-valued signal from its Fourier intensity. Due to the well-known ambiguousness of this problem, the determination of the original signal within the extensive…

Numerical Analysis · Mathematics 2021-03-19 Robert Beinert

Phase retrieval is in general a non-convex and non-linear task and the corresponding algorithms struggle with the issue of local minima. We consider the case where the measurement samples within typically very small and disconnected subsets…

Signal Processing · Electrical Eng. & Systems 2022-06-28 Jonas Kornprobst , Alexander Paulus , Josef Knapp , Thomas F. Eibert

The line spectral estimation problem consists in recovering the frequencies of a complex valued time signal that is assumed to be sparse in the spectral domain from its discrete observations. Unlike the gridding required by the classical…

Information Theory · Computer Science 2021-10-18 Maxime Ferreira Da Costa , Wei Dai

Phase retrieval (PR) aims to recover a signal from the magnitudes of a set of inner products. This problem arises in many audio signal processing applications which operate on a short-time Fourier transform magnitude or power spectrogram,…

Sound · Computer Science 2021-02-24 Pierre-Hugo Vial , Paul Magron , Thomas Oberlin , Cédric Févotte

In many applications and physical phenomena, bivariate signals are polarized, i.e. they trace an elliptical trajectory over time when viewed in the 2D planes of their two components. The smooth evolution of this elliptical trajectory,…

Signal Processing · Electrical Eng. & Systems 2025-06-26 Yusuf Yigit Pilavci , Pierre Palud , Julien Flamant , Pierre-Antoine Thouvenin , Jérémie Boulanger , Pierre Chainais

Optical two-dimensional (2D) coherent spectroscopy excels in studying coupling and dynamics in complex systems. The dynamical information can be learned from lineshape analysis to extract the corresponding linewidth. However, it is usually…

Optics · Physics 2020-06-24 Srikanth Namuduri , Michael Titze , Shekhar Bhansali , Hebin Li

Generally, wave field reconstructions obtained by phase-retrieval algorithms are noisy, blurred and corrupted by various artifacts such as irregular waves, spots, etc. These disturbances, arising due to many factors such as non-idealities…

Optics · Physics 2012-07-24 Artem Migukin , Mostafa Agour , Vladimir Katkovnik

We propose a robust and efficient approach to the problem of compressive phase retrieval in which the goal is to reconstruct a sparse vector from the magnitude of a number of its linear measurements. The proposed framework relies on…

Information Theory · Computer Science 2015-10-28 Sohail Bahmani , Justin Romberg

We present a new four-dimensional phase unwrapping approach for time-lapse quantitative phase microscopy, which allows reconstruction of optically thick objects that are optically thin in a certain temporal point and angular view. We thus…

Optics · Physics 2019-09-04 Gili Dardikman , Gyanendra Singh , Natan T. Shaked

A recently proposed convex formulation of the phase retrieval problem estimates the unknown signal by solving a simple linear program. This new scheme, known as PhaseMax, is computationally efficient compared to standard convex relaxation…

Information Theory · Computer Science 2017-10-17 Oussama Dhifallah , Christos Thrampoulidis , Yue M. Lu

In this paper, we consider the highly ill-posed problem of jointly recovering two real-valued signals from the phaseless measurements of their circular convolution. The problem arises in various imaging modalities such as Fourier…

Image and Video Processing · Electrical Eng. & Systems 2020-03-02 Fahad Shamshad , Ali Ahmed

Reconstructing continuous signals from a small number of discrete samples is a fundamental problem across science and engineering. In practice, we are often interested in signals with 'simple' Fourier structure, such as bandlimited,…

Data Structures and Algorithms · Computer Science 2018-12-24 Haim Avron , Michael Kapralov , Cameron Musco , Christopher Musco , Ameya Velingker , Amir Zandieh

We consider the problem of recovering fusion frame sparse signals from incomplete measurements. These signals are composed of a small number of nonzero blocks taken from a family of subspaces. First, we show that, by using a-priori…

Information Theory · Computer Science 2014-07-30 Ulaş Ayaz , Sjoerd Dirksen , Holger Rauhut

Neuromorphic sampling is a paradigm shift in analog-to-digital conversion where the acquisition strategy is opportunistic and measurements are recorded only when there is a significant change in the signal. Neuromorphic sampling has given…

Signal Processing · Electrical Eng. & Systems 2023-06-09 Abijith Jagannath Kamath , Chandra Sekhar Seelamantula