Publications associées à Objectif fisheye

Laser-based manufacturing of freeform glass micro-optics through topological transformation

Glass has been the material of choice for making optical elements, in large part due to its intrinsic properties: a temperature-dependent viscosity, which enables shaping the material into a broad variety of functional and artistic glassware. Silica glass ...

EPFL2024

Searching for Strong Gravitational Lenses

Frédéric Courbin, Cameron Alexander Campbell Lemon

Strong gravitational lenses provide unique laboratories for cosmological and astrophysical investigations, but they must first be discovered - a task that can be met with significant contamination by other astrophysical objects and asterisms. Here we revie ...

Springer2024

LensWatch. I. Resolved HST Observations and Constraints on the Strongly Lensed Type Ia Supernova 2022qmx ("SN Zwicky")

Frédéric Courbin, Adriano Agnello

Supernovae (SNe) that have been multiply imaged by gravitational lensing are rare and powerful probes for cosmology. Each detection is an opportunity to develop the critical tools and methodologies needed as the sample of lensed SNe increases by orders of ...

IOP Publishing Ltd2023

The ellipticity parameterization for an NFW profile: An overlooked angular structure in strong lens modeling

Frédéric Courbin

Galaxy-scale gravitational lenses are often modeled with two-component mass profiles where one component represents the stellar mass and the second is a Navarro Frenk White (NFW) profile representing the dark matter. Outside of the spherical case, the NFW ...

Edp Sciences S A2023

MaxwellNet: Physics-driven deep neural network training based on Maxwell's equations

Demetri Psaltis, Joowon Lim

Maxwell's equations govern light propagation and its interaction with matter. Therefore, the solution of Maxwell's equations using computational electromagnetic simulations plays a critical role in understanding light-matter interaction and designing optic ...

AIP Publishing2022

SLITRONOMY: Towards a fully wavelet-based strong lensing inversion technique

Frédéric Courbin, Aymeric Alexandre Galan, Austin Chandler Peel, Rémy Elie Joseph

Strong gravitational lensing provides a wealth of astrophysical information on the baryonic and dark matter content of galaxies. It also serves as a valuable cosmological probe by allowing us to measure the Hubble constant independently of other methods. T ...

EDP SCIENCES S A2021

Measuring accretion disk sizes of lensed quasars with microlensing time delay in multi-band light curves

Frédéric Courbin, Vivien François Bonvin, Hung-Hsu Chan, Martin Raoul Robert Millon, Karina Alexandra Rojas Olate

Time-delay cosmography in strongly lensed quasars offers an independent way of measuring the Hubble constant, H-0. However, it has been proposed that the combination of microlensing and source-size effects, also known as microlensing time delay, can potent ...

EDP SCIENCES S A2021

Fixed-wing micro UAV open data with digicam and raw INS/GNSS

Jan Skaloud, Davide Antonio Cucci, Kenneth Joseph Paul

We have recently released in the open domain data originating from a series of flights conducted with a fixed-wing micro UAV carrying high-quality small camera and navigation sensors. This data was previously used in several peer-reviewed publications. How ...

2021

Time-delay Cosmography with Strongly Lensed Quasars

Martin Raoul Robert Millon

The LCDM model has emerged as the concordance model of cosmology for its ability to explain a variety of observations, ranging from the anisotropies of the Cosmic Microwave Background (CMB) to the accelerated expansion of the Universe. However, with the ev ...

EPFL2021

Koehler integrator device and application thereof in a multi-focal confocal microscope

Suliana Manley, Kyle Michael Douglass, Dora Mahecic

A Koehler integrator device (10) comprises a collimating lens (11) being arranged for collimating a light field created by an incoherent or partially coherent light source, a pair of planar first and second micro-lens arrays (12, 13) being arranged for rel ...

2020

COSMOGRAIL: XIX. Time delays in 18 strongly lensed quasars from 15 years of optical monitoring star

Frédéric Courbin, Georges Meylan, Malte Tewes, Eric Gérard Guy Paic, Vivien François Bonvin, Hung-Hsu Chan, Olga Tihhonova, Martin Raoul Robert Millon, Aymeric Alexandre Galan, Rémy Elie Joseph, Cameron Alexander Campbell Lemon

We present the results of 15 years of monitoring lensed quasars, which was conducted by the COSMOGRAIL programme at the Leonhard Euler 1.2 m Swiss Telescope. The decade-long light curves of 23 lensed systems are presented for the first time. We complement ...

EDP SCIENCES S A2020

H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H-0

Frédéric Courbin, Vivien François Bonvin, Hung-Hsu Chan

We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033 - 4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 yr of data obtained by the COSm ...

OXFORD UNIV PRESS2020

Moiré effects produced by superpositions of micro-lens arrays

Thomas Walger

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

Learning stereo reconstruction with deep neural networks

Stepan Tulyakov

Stereo reconstruction is a problem of recovering a 3d structure of a scene from a pair of images of the scene, acquired from different viewpoints. It has been investigated for decades and many successful methods were developed. The main drawback of these ...

EPFL2020

1D moiré shapes by superposed layers of micro-lenses

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

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 animated moirés when th ...

2019

Closed-Form Solution to Disambiguate Defocus Blur in Single-Perspective Images

Sabine Süsstrunk, Majed El Helou, Marjan Shahpaski

Depth-from-defocus techniques suffer an ambiguity problem where depth planes on opposite sides of the focal plane have identical defocus. We solve the ambiguity by relying on the wavelength-dependent relationship between defocus and depth. We conduct a rob ...

2019

Mo(2)Cap(2): Real-time Mobile 3D Motion Capture with a Cap-mounted Fisheye Camera

Pascal Fua, Helge Jochen Rhodin

We propose the first real-time system for the egocentric estimation of 3D human body pose in a wide range of unconstrained everyday activities. This setting has a unique set of challenges, such as mobility of the hardware setup, and robustness to long capt ...

2019

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

Quasi-stellar objects acting as potential strong gravitational lenses in the SDSS-III BOSS survey

Jean-Paul Richard Kneib, Frédéric Courbin, Timothée Guy Olivier Delubac

We present a sample of 12 quasi-stellar objects (QSOs) that potentially act as strong gravitational lenses on background emission line galaxies (ELG) or Lyman-alpha emitters (LAEs) selected through a systematic search of the 297 301 QSOs in the Sloan Digit ...

EDP SCIENCES S A2019

Are Photonic Nanojets Achromatic?

Toralf Scharf, Myun Sik Kim, Michail Symeonidis

In this work we study the evolution of the photonic nanojet (PNJ) phenomenon as the ratio of the sphere's diameter over the illumination wavelength changes, for microspheres with diameters from 2 mu m to 100 mu m. We measure the focal point position by usi ...

SPIE-INT SOC OPTICAL ENGINEERING2019