Publications associées à Estimation of phase derivatives using discrete energy separation algorithm in digital holographic interferometry

Computation of "Best" Interpolants in the Lp Sense

We study a variant of the interpolation problem where the continuously defined solution is regularized by minimizing the L p -norm of its second-order derivative. For this continuous-domain problem, we propose an exact discretization scheme that restricts ...

2020

Continuous-Domain Signal Reconstruction Using L-p-Norm Regularization

Michaël Unser, Pakshal Narendra Bohra

We focus on the generalized-interpolation problem. There, one reconstructs continuous-domain signals that honor discrete data constraints. This problem is infinite-dimensional and ill-posed. We make it well-posed by imposing that the solution balances data ...

2020

On design strategies for binary dielectric metasurfaces based on the Fourier modal method

Kévin Müller

Binary dielectric metasurfaces are arrays of sub-wavelength structures that act as a thin layer of artificial material. They are generally lossless and relatively simple to fabricate since only a single structuring step is required. By carefully designing ...

EPFL2020

All-Dielectric Programmable Huygens' Metasurfaces

Hatice Altug, Andreas Tittl, Aleksandrs Leitis

Low-loss nanostructured dielectric metasurfaces have emerged as a breakthrough platform for ultrathin optics and cutting-edge photonic applications, including beam shaping, focusing, and holography. However, the static nature of their constituent materials ...

2020

Bayesian estimation of mixed multinomial logit models: Advances and simulation-based evaluations

Michel Bierlaire, Prateek Bansal

Variational Bayes (VB) methods have emerged as a fast and computationally-efficient alternative to Markov chain Monte Carlo (MCMC) methods for scalable Bayesian estimation of mixed multinomial logit (MMNL) models. It has been established that VB is substan ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Domain-Informed Spline Interpolation

Dimitri Nestor Alice Van De Ville, Zafer Dogan, Hamid Behjat

Standard interpolation techniques are implicitly based on the assumption that the signal lies on a single homogeneous domain. In contrast, many naturally occurring signals lie on an inhomogeneous domain, such as brain activity associated to different brain ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

Measurement of Displacement and Its Derivatives from a Phase Fringe Pattern

Pramod Rastogi, Rishikesh Dilip Kulkarni

Noting the fact that the phase and phase derivatives carry the information on the mechanical deformation in optical interferometric measurements techniques, we propose a noise robust fringe analysis technique for the simultaneous estimation of unwrapped ph ...

SPRINGER INTERNATIONAL PUBLISHING AG2019

Diffractive Optical Elements Investigation in the Phase Domain

Myun Sik Kim, Toralf Scharf, Michail Symeonidis, Dong Cheon Kim

In this work we demonstrate the advantages of investigating diffractive optical elements in the phase domain. In this regime we can detect features that are not restrained by the diffraction limit and relate them to the geometrical and optical properties o ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Phase resolved characterization of nanoscale features in optical microstructures

Michail Symeonidis

In this study, we apply interferometric microscopy to study the phase, alongside the intensity, of the light field transmitted through a wide variety of samples. Additionally, we conduct those interferometric measurements at different wavelengths within th ...

EPFL2019

Estimation of Phase and Its Higher Order Derivatives from a Single Complex Interferogram

Pramod Rastogi, Rishikesh Dilip Kulkarni

This paper reports a method for the simultaneous estimation of unwrapped phase and higher order phase derivatives from a single phase fringe pattern recorded in an optical interferometric setup, thereby overcoming substantial barriers to achieving such mea ...

2016

Spatial fringe analysis techniques for multiple phase and phase derivative estimation

Rishikesh Dilip Kulkarni

Analysis of fringe patterns for the accurate estimation of phase and phase derivatives is of crucial importance in optical interferometry as these quantities provide important information on the physical parameters under study. A wide range of applications ...

EPFL2016

Hermite Snakes with Control of Tangents

Michaël Unser, Virginie Sophie Uhlmann, Julien René Pierre Fageot

We introduce a new model of parametric contours defined in a continuous fashion. Our curve model relies on Hermite spline interpolation and can easily generate curves with sharp discontinuities; it also grants direct access to the tangent at each location. ...

IEEE2016

Simultaneous estimation of unwrapped phase and phase derivative from a closed fringe pattern

Pramod Rastogi, Rishikesh Dilip Kulkarni

We propose a new approach for the direct estimation of the unwrapped phase from a single closed fringe pattern. The fringe analysis is performed along a given row/column at a time by approximating the phase with a weighted linear combination of linearly in ...

2016

Lightfields behind amplitude masks: Creating phase discontinuities

Hans Peter Herzig, Wilfried Noell, Myun Sik Kim, Toralf Scharf, Krishnaparvathy Puthankovilakam

Shaping of light fields behind amplitude and phase masks the basis the lithographic structure reproduction. The aerial image or better the intensity distribution defines the resolution of the structure to be printed. Contrast is the main parameter and to a ...

Ieee2016

Multiple phase derivative estimation using autoregressive modeling in holographic interferometry

Pramod Rastogi, Rishikesh Dilip Kulkarni

A novel technique is proposed for the direct and simultaneous estimation of multiple phase derivatives from a deformation modulated carrier fringe pattern in a multi-wave holographic interferometry set-up. The fringe intensity is represented as a spatially ...

Institute of Physics2015

Femtosecond diffractive imaging of structures, charge and spin textures

Giulia Fulvia Mancini

The study of the dynamical evolution of a system, e.g. a chemical reaction or a phase transition, has become nowadays a subject of growing scientific interest. The direct observation of the steps and the structural changes through which chemical reactions ...

EPFL2015

Sampling and (Sparse) Stochastic Processes: A Tale of Splines and Innovation

Michaël Unser

The commonality between splines and Gaussian or sparse stochastic processes is that they are ruled by the same type of differential equations. Our purpose here is to demonstrate that this has profound implications for the three primary forms of sampling: u ...

IEEE2015

Acquisition of multiple phase derivatives from a single frame in digital holographic interferometry

Pramod Rastogi, Rishikesh Dilip Kulkarni

This paper proposes a technique to extract two-dimensional multiple phase derivatives (strains, slopes, and shearing strains) from a single frame of the interference fringe pattern recorded in an optical setup with multiple illumination beams. In the propo ...

Spie-Soc Photo-Optical Instrumentation Engineers2015

Interior Tomography Using 1D Generalized Total Variation. Part I: Mathematical Foundation

Michaël Unser, John Paul Ward

Motivated by the interior tomography problem, we propose a method for exact reconstruction of a region of interest of a function from its local Radon transform in any number of dimensions. Our aim is to verify the feasibility of a one-dimensional reconstru ...

Siam Publications2015

Heuristic strategies for the approximation of stability factors in quadratically nonlinear parametrized PDEs

Andrea Manzoni, Federico Negri

In this paper we present some heuristic strategies to compute rapid and reliable approximations to stability factors in nonlinear, inf-sup stable parametrized PDEs. The efficient evaluation of these quantities is crucial for the rapid construction of a pos ...

Springer Verlag2015