Publications associées à Method, system and computer program for determining a reflectance distribution function of an object

Practical Byzantine-resilient Stochastic Gradient Descent

Algorithms are everywhere. The recipe for the frangipane cake is an algorithm. If all the listed ingredients are available and the cook is sufficiently deft, after a finite number of small, well-defined steps a delicious dessert will exit the oven. Now, wh ...

EPFL2022

Pitfalls in the spectral measurements of polarization-altering metasurfaces

Olivier Martin, Hsiang-Chu Wang

The optical characterization of metasurfaces and nanostructures that alter the polarization of light is tricky and can lead to unphysical results, such as reflectance beyond unity. We track the origin of such pitfalls to the response of some typical optica ...

Optica Publishing Group2022

Effects of illuminance intensity on the green channel of remote photoplethysmography (rPPG) signals

Ata Jedari Golparvar

Point-of-care remote photoplethysmography (rPPG) devices that utilize low-cost RGB cameras have drawn considerable attention due to their convenience in contactless and non-invasive vital signs monitoring. In rPPG, sufficient lighting conditions are essent ...

SPRINGER2022

Light Path Gradients for Forward and Inverse Rendering

Tizian Lucien Zeltner

Physically based rendering is a process for photorealistic digital image synthesis and one of the core problems in computer graphics. It involves simulating the light transport, i.e. the emission, propagation, and scattering of light through a virtual scen ...

EPFL2021

Precise and accurate image-based measurements of optical material properties

Marjan Shahpaski

The appearance of objects is governed by how they reflect, transmit and absorb the light they receive. That, in turn, depends on the material's internal structure, surface structure, and viewing and illumination directions. Changes in those characteristics ...

EPFL2020

Effects of multiple scattering on angle-independent structural color in disordered colloidal materials

Sofia Magkiriadou

Disordered packings of colloidal spheres show angle-independent structural color when the particles are on the scale of the wavelength of visible light. Previous work has shown that the positions of the peaks in the reflectance spectra can be predicted acc ...

AMER PHYSICAL SOC2020

Large field of view multi-camera endoscopic apparatus with omni-directional illumination

Yusuf Leblebici, Ömer Cogal

A multi-camera hemispherical very wide field of view imaging apparatus with omnidirectional illumination capability comprises a cylindrical body (4, 4.a, 4.b), a hemispherical mechanical frame (2) arranged on one end of the cylindrical body (4, 4.a, 4.b), ...

2020

Ultra-Broadband and Omnidirectional Perfect Absorber Based on Copper Nanowire/Carbon Nanotube Hierarchical Structure

Giulia Tagliabue, Fateme Kiani Shahvandi, Theodoros Tsoulos

Zero reflection and complete light absorption are required in a wide range of applications ranging from sensing devices to solar heaters and photoelectrodes. However, simultaneously satisfying the requirements of the broadband spectrum, omnidirectionality, ...

AMER CHEMICAL SOC2020

System for personalized robotic therapy and related methods

Nawal Noëlle Kinany, Elvira Pirondini, Silvestro Micera, Christian Giang, Camilla Pierella

The present invention provides an apparatus and a method able to estimate motor improvement in real-time during three-dimensional rehabilitation tasks and to consequently dynamically personalize the therapy.The method can be carried out by a computer progr ...

2019

Sampling the Multiple Facets of Light

Gilles Baechler

The theme of this thesis revolves around three important manifestations of light, namely its corpuscular, wave and electromagnetic nature. Our goal is to exploit these principles to analyze, design and build imaging modalities by developing new signal proc ...

EPFL2018

A Comparison between Two Automatic Assessment Approaches for Programming: An Empirical Study on MOOCs

Pierre Dillenbourg, Patrick Jermann

Computer-graders have been in regular use in the context of MOOCs (Massive Open Online Courses). The automatic grading of programs presents an opportunity to assess and provide tailored feedback to large classes, while featuring at the same time a number o ...

2018

Distributed analyses using distinct classes of Brillouin scatterings in optical fibres

Desmond Chow Ming Chia

Brillouin scattering is an interaction between light and sound in a material. This inelastic light scattering had been observed in the first optical fibres that were used in cross-continent communication. Via Brillouin scattering, the guided light wave in ...

EPFL2018

Phase Bifurcation and Zero Reflection in Planar Plasmonic Metasurfaces

Olivier Martin, Chen Yan

We introduce a general formalism combining the coupled oscillator model with the transfer matrix method to analyze and engineer the phase of the light reflected from a Fano-resonant metasurface. This method accounts for periodicity and the presence of subs ...

2017

Large Field of View Multi-Camera Endoscopic Apparatus with Omni-Directional Illumination

Yusuf Leblebici, Ömer Cogal

A multi-camera hemispherical very wide field of view imaging apparatus with omnidirectional illumination capability comprises a cylindrical body (4, 4.a, 4.b), a hemispherical mechanical frame (2) arranged on one end of the cylindrical body (4, 4.a, 4.b), ...

2017

Apparatus for imaging a page of a book or other similar document

Martin Vetterli, Loïc Arnaud Baboulaz

The present invention relates to an apparatus for imaging a page of a book or other similar document comprising: - a table defining a support plane, the book being disposed on the table such that the page to image is substantially parallel to the support p ...

2017

Self-Tracking Solar Concentrator Device

Jacques-Edouard Moser, Volker Günter Zagolla, Christophe Moser

A device for self-tracking a light source, including a focusing optical device configured to focus incoming light to a focal spot, an adaptive device configured to reflect the light of the focal spot and arranged to provide for a phase change at an area of ...

2016

Device for photoactivation and reaction monitoring

Dominique Pioletti, Pierre-Etienne Bourban, Andreas Schmocker, Christophe Moser

The present invention relates to a device to photocure and/or photoactivate a photosensitive material. The device comprises several subsystems to transmit light towards an area of interest where a photosensitive material is applied as well as to collect li ...

2016

Transition of optical regime in miniaturized optical systems: light interactions beyond the refraction limit

Hans Peter Herzig, Myun Sik Kim, Toralf Scharf

We investigate the transition of optical regimes of miniaturized optical systems using two canonical examples, where the refraction of light limits the system performance. A ball-lens and a solid immersion lens (SIL) are considered, whose refractive respon ...

Spie-Int Soc Optical Engineering2016

Transflective holographic film for head worn display

Jürgen Brugger, Jonas Grossenbacher, Victor Javier Cadarso Busto, Christophe Moser, Eric Tremblay

A display panel assembly comprises a transflective holographic screen, i.e., a transparent screen that reflects light from a projection system, comprising at least a volume hologram, a first protective element and a second protective element, each arranged ...

2015

Microstructured glazing for daylighting, glare protection, seasonal thermal control and clear view

André Gabriel Kostro

The appropriate choice of glazing in a facade depends on many factors. They include amongst other criteria: location, orientation, climatic condition, energetic efficiency, usage of the building, required user comfort, and the architectural concept. On the ...

EPFL2015