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Image steganography is the art of hiding secret message in grayscale or color images. Easy detection of secret message for any state-of-art image steganography can break the stego system. To prevent the breakdown of the stego system data is…

Multimedia · Computer Science 2022-01-05 Soumendu Chakraborty , Anand Singh Jalal , Charul Bhatnagar

For many profilometry techniques, phase unwrapping is one of the most challenging process. In order to sidestep the phase unwrapping process, Perciante et. al [Appl Opt 2015; 54(10):3018-23] proposed a wrapping-free method based on the…

Data Analysis, Statistics and Probability · Physics 2017-06-28 Minmin Wang , Canlin Zhou , Shuchun Si , XiaoLei Li , Zhenkun Lei , YanJie Li

In this work, we demonstrate that the ptychographic phase problem can be solved in a live fashion during scanning, while data is still being collected. We propose a generally applicable modification of the widespread projection-based…

Image and Video Processing · Electrical Eng. & Systems 2023-09-20 Simon Welker , Tal Peer , Henry N. Chapman , Timo Gerkmann

A cascadic multigrid method is proposed for the GPE problem based on the multilevel correction scheme. With this new scheme, the ground state eigenvalue problem on the finest space can be solved by smoothing steps on a series of multilevel…

Numerical Analysis · Mathematics 2015-04-22 Xiaole Han , Hehu Xie

Reconstructing dynamic objects from monocular videos is a severely underconstrained and challenging problem, and recent work has approached it in various directions. However, owing to the ill-posed nature of this problem, there has been no…

Computer Vision and Pattern Recognition · Computer Science 2024-04-02 Devikalyan Das , Christopher Wewer , Raza Yunus , Eddy Ilg , Jan Eric Lenssen

The geometric multigrid algorithm is an efficient numerical method for solving a variety of elliptic partial differential equations (PDEs). The method damps errors at progressively finer grid scales, resulting in faster convergence compared…

Numerical Analysis · Mathematics 2024-03-14 Francisco Holguin , GS Sidharth , Gavin Portwood

We present \code{phaser}, an open-source Python package that provides a unified interface to both conventional and gradient descent-based ptychographic algorithms. Features such as mixed-state probe, probe position correction, and…

Computational Physics · Physics 2025-07-21 Colin Gilgenbach , Menglin Zhu , James M. LeBeau

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

The problem of phase retrieval has been intriguing researchers for decades due to its appearance in a wide range of applications. The task of a phase retrieval algorithm is typically to recover a signal from linear phase-less measurements.…

Signal Processing · Electrical Eng. & Systems 2020-03-11 Naveed Naimipour , Shahin Khobahi , Mojtaba Soltanalian

Transmission expansion planning (TEP) plays a critical role in ensuring power system reliability and facilitating the integration of renewable energy resources. However, this process requires planners to constantly deal with significant…

Systems and Control · Electrical Eng. & Systems 2026-04-21 Victor Schmitt , Farzaneh Pourahmadi , Angela Flores-Quiroz , Pablo Apablaza , Pierluigi Mancarella

This paper proposes a new framework to regularize the highly ill-posed and non-linear phase retrieval problem through deep generative priors using simple gradient descent algorithm. We experimentally show effectiveness of proposed algorithm…

Machine Learning · Computer Science 2018-08-20 Fahad Shamshad , Ali Ahmed

Phase reconstruction is important in transmission electron microscopy for structural studies. We describe electron Fourier ptychography and its application to phase reconstruction of both radiation-resistant and beam-sensitive materials. We…

Recovering the transmission matrix of a disordered medium is a challenging problem in disordered photonics. Usually, its reconstruction relies on a complex inversion that aims at connecting a fully-controlled input to the deterministic…

Separable multi-block convex optimization problem appears in many mathematical and engineering fields. In the first part of this paper, we propose an inertial proximal ADMM to solve a linearly constrained separable multi-block convex…

Numerical Analysis · Mathematics 2020-12-29 Peng Li , Wengu Chen , Qiyu Sun

The classical problem of phase retrieval arises in various signal acquisition systems. Due to the ill-posed nature of the problem, the solution requires assumptions on the structure of the signal. In the last several years, sparsity and…

Computer Vision and Pattern Recognition · Computer Science 2019-03-08 Rakib Hyder , Viraj Shah , Chinmay Hegde , M. Salman Asif

We present an iterative scheme, reminiscent of the Multigrid method, to solve large boundary value problems with Probabilistic Domain Decomposition (PDD). In it, increasingly accurate approximations to the solution are used as control…

Numerical Analysis · Mathematics 2017-01-06 Francisco Bernal , Juan A. Acebrón

In this article, we address the issue of recovering latent transparent layers from superimposition images. Here, we assume we have the estimated transformations and extracted gradients of latent layers. To rapidly recover high-quality image…

Computer Vision and Pattern Recognition · Computer Science 2012-11-20 Han Li , Kun Gai , Pinghua Gong , Changshui Zhang

Ptychography is a lensless imaging technique, which considers reconstruction from a set of far-field diffraction patterns obtained by illuminating small overlapping regions of the specimen. In many cases, a distribution of light inside the…

Numerical Analysis · Mathematics 2022-10-05 Frank Filbir , Oleh Melnyk

This paper presents our approach to the NTIRE 2026 3D Restoration and Reconstruction Challenge (Track 1), which focuses on reconstructing high-quality 3D representations from degraded multi-view inputs. The challenge involves recovering…

Computer Vision and Pattern Recognition · Computer Science 2026-05-12 Yuhao Liu , Dingju Wang , Ziyang Zheng

Phase retrieval is a nonlinear inverse problem that arises in a wide range of imaging modalities, from electron microscopy to Fourier ptychography. In particular, the reconstruction is facilitated when the sensing matrix is i.i.d. random,…