Publications associées à Simultaneous measurement of in-plane and out-of-plane displacements using pseudo-Wigner-Hough transform

Moiré effects produced by superpositions of micro-lens arrays

Moiré effects result from the superimposition of repetitive structures. The beauty of these moirés comes from the fact that macroscopic shapes seem to appear from the superposition of layers containing microscopic patterns. In addition, the moirés are dyna ...

EPFL2020

Level-line moirés by superposition of cylindrical microlens gratings

Roger Hersch, Jürgen Brugger, Valentin Flauraud, Théophane Besson, Thomas Walger

Two superposed layers of transparent cylindrical lenslet gratings create classical moiré fringes when illuminated from behind. We rely on this observation to conceive special devices made of superposed lenslet gratings that produce compelling beating shape ...

2020

Holographic imaging of electromagnetic fields via electron-light quantum interference

Fabrizio Carbone, Ivan Madan, Enrico Pomarico, Tom Theodorus Antonius Lummen, Gabriele Berruto, Giovanni Maria Vanacore, Tatiana Latychevskaia

Holography relies on the interference between a known reference and a signal of interest to reconstruct both the amplitude and the phase of that signal. With electrons, the extension of holography to the ultrafast time domain remains a challenge, although ...

American Association for the Advancement of Science (AAAS)2019

Signal Analysis Based on Complex Wavelet Signs

Martin Kurt Storath

We propose a signal analysis tool based on the sign (or the phase) of complex wavelet coefficients, which we call a signature. The signature is defined as the fine-scale limit of the signs of a signal's complex wavelet coefficients. We show that the signat ...

Elsevier2017

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

Patch-wise denoising of phase fringe patterns based on matrix enhancement

Pramod Rastogi, Rishikesh Dilip Kulkarni

We propose a new approach for the denoising of a phase fringe pattern recorded in an optical interferometric setup. The phase fringe pattern which is generally corrupted by high amount of speckle noise is first converted into an exponential phase field. Th ...

2016

Multiple phase estimation via signal separation using a windowed Fourier transform in digital holographic interferometry

Pramod Rastogi, Rishikesh Dilip Kulkarni

This paper proposes a novel method for the simultaneous estimation of multiple interference phases from a single recording of the interference field in a multi-wave digital holographic interferometry set-up. The method involves the separation of signal com ...

Institute of Physics2015

Three-dimensional displacement measurement from phase signals embedded in a frame in digital holographic interferometry

Pramod Rastogi, Rishikesh Dilip Kulkarni

A novel technique is proposed for the simultaneous measurement of all three components of displacement from a single recording of the interference field in digital holographic interferometry. The interference field is divided into a number of rectangular s ...

Optical Soc Amer2015

Iterative signal separation based multiple phase estimation in digital holographic interferometry

Pramod Rastogi, Rishikesh Dilip Kulkarni

We propose a new method for signal separation from a multicomponent interference field recorded in a digital holographic interferometry setup. The setup consisting of multiple object illuminating beams results in an interference field containing multiple s ...

Optical Society of America2015

Towards an incoherent off-axis digital holographic microscope

Frédéric Montfort, Christian Depeursinge

We propose and experimentally demonstrate a system in which off-axis digital holographic microscopy is realized using a broadband illumination source. Single-shot holographic measurements are enabled, while the coherence noise is removed thanks to the broa ...

Spie-Int Soc Optical Engineering2015

Brillouin dynamic gratings in optical fibres for distributed sensing and advanced optical signal processing

Andrey Denisov

This thesis presents results of a research on applications of Brillouin dynamic gratings - distributed reflectors that can be dynamically created in an optical fibre by two optical waves. A basic theory of stimulated Brillouin scattering (SBS) is introduce ...

EPFL2015

Measurement of in-plane and out-of-plane displacements and strains using digital holographic moiré

Pramod Rastogi, Sai Siva Gorthi, Rishikesh Dilip Kulkarni

The paper proposes a non-destructive method for simultaneous measurement of in-plane and out-of-plane displacements and strains undergone by a deformed specimen from a single moire fringe pattern obtained on the specimen in a dual beam digital holographic ...

Taylor & Francis2014

Off-axis digital holographic camera for quantitative phase microscopy

Frédéric Montfort, Christian Depeursinge, Christophe Moser, Zahra Monemhaghdoust

We propose and experimentally demonstrate a digital holographic camera which can be attached to the camera port of a conventional microscope for obtaining digital holograms in a self-reference configuration, under short coherence illumination and in a sing ...

Optical Soc Amer2014

Full field vertical scanning in short coherence digital holographic microscope

Frédéric Montfort, Etienne Cuche, Christian Depeursinge, Christophe Moser

In Digital holography Microscopes (DHM) implemented in the so-called "off axis" configuration, the object and reference wave fronts are not co-planar but form an angle of a few degrees. This results into two main drawbacks. First, the contrast of the inter ...

Optical Soc Amer2013

Multiple phase estimation in digital holographic interferometry using product cubic phase function

Pramod Rastogi, Rishikesh Dilip Kulkarni

Digital holographic interferometry (DHI) involves multi-directional illumination of an object to measure the in-plane and out-of plane displacements simultaneously. This results in multiple interference phases which have to be reliably estimated. The paper ...

Elsevier2013

Estimation of multiple phases from a single fringe pattern in digital holographic interferometry

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

Simultaneous measurement of multidimensional displacements using digital holographic interferometry involves multi-directional illumination of the deformed object and requires the reliable estimation of the resulting multiple interference phase distributio ...

Optical Society of America2012

Phase Gradient Estimation Techniques in Fringe Analysis

Rajshekhar Gannavarpu

The thesis introduces novel techniques in the field of fringe analysis for direct estimation of phase gradients or derivatives. A pseudo Wigner-Ville distribution based method is proposed to reliably estimate the phase derivatives from a single fringe patt ...

EPFL2012

Simultaneous multidimensional deformation measurements using digital holographic moiré

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

This paper proposes an elegant technique for the simultaneous measurement of in-plane and out-of-plane displacements of a deformed object in digital holographic interferometry. The measurement relies on simultaneously illuminating the object from multiple ...

Optical Society of America2011

Complex index refraction tomography with sub ?/6-resolution

Christian Depeursinge, Nicolas Pavillon, Yann Jérôme Michel Pascal Cotte

The present invention discloses a method to improve the image resolution of a microscope. This improvement is based on the mathematical processing of the complex field computed from the measurements with a microscope of the wave emitted or scattered by the ...

2011

Phase extraction in speckle interferometry by a circle fitting procedure in the complex plane

Pierre Jacquot, Sébastien Equis

In speckle interferometry (SI), temporal signals are amplitude- and frequency-modulated signals and exhibit a fluctuating background. Prior to phase computation, this background intensity must be eliminated. Here our approach is to build a complex signal f ...

Optical Society of America2011