Publications related to Lightness

Seeing Photons in Color

Edoardo Charbon, Claudio Bruschini, Paul Mos, Mohit Gupta

Megapixel single-photon avalanche diode (SPAD) arrays have been developed recently, opening up the possibility of deploying SPADs as general-purpose passive cameras for photography and computer vision. However, most previous work on SPADs has been limited ...

ASSOC COMPUTING MACHINERY2023

Wide Gamut Spectral Upsampling with Fluorescence

Wenzel Alban Jakob

Physically based spectral rendering has become increasingly important in recent years. However, asset textures in such systems are usually still drawn or acquired as RGB tristimulus values. While a number of RGB to spectrum upsampling techniques are availa ...

2019

Angular Color Prediction Model for Anisotropic Halftone Prints on a Metallic Substrate

Roger Hersch, Lin Yang, Petar Pjanic

Under specular reflection, non-isotropic halftones such as line halftones printed on an ink-receiving plastic layer superposed with a metallic layer change their colors upon in-plane rotation of the print. This color change is due to the orientation-depend ...

I S & T-SOC IMAGING SCIENCE TECHNOLOGY2019

Laminated glazing with coloured reflection and high solar transmittance suitable for solar energy systems

Andreas Schueler, Josef Andreas Schuler, Virginie Hody-Le Caër

Laminated and etched glazing unit for architectural integration of solar energy systems comprising a substrate delimited by two main faces and a multi-layered interference filter also delimited by two main faces, one main face of said substrate being adapt ...

2017

Image reproduction with compensation of luminance adaptation

Mahmut Sami Arpa

We introduce an image reproduction model that retargets colors for printing purposes to ensure similar luminance perception under photopic and scotopic vision. Our model is based on the physiological functioning of the rod and cone cells in the retina in v ...

Springer London Ltd2017

Put on that colour, it fits your emotion: Colour appropriateness as a function of expressed emotion

Christine Mohr, Cynthia Marchand

People associate affective meaning with colour, and this may influence decisions about colours. Hue is traditionally considered the most salient descriptor of colour and colour-affect associations, although colour brightness and saturation seem to have par ...

Routledge Journals, Taylor & Francis Ltd2016

Human responsive daylighting in offices : a gaze-driven approach for dynamic discomfort glare assessment

Mandana Sarey Khanie

This dissertation proposes a novel gaze-driven approach for dynamic discomfort glare assessments as a first step towards understanding human responsive comfort with respect to daylight. The objective was to observe the natural gaze behaviour in relation to ...

EPFL2015

Color Reproduction with Juxtaposed Halftoning

Vahid Babaei

Recently, non-standard inks have begun to make their way into the world of printing. Non-standard inks are printing materials which exhibit unusual effects such as angular color dependence, texture, or fluorescence. They are made of special-effect pigments ...

EPFL2015

Color Reproduction of Authenticable Luminescent Backlit Transmissive Color Images

Roger Hersch, Julien Alexandre Andres

We propose a method for creating authenticable color images under UV excitation backlight by printing an invisible luminescent white emissive ink layer on the verso side of a transmissive substrate and a classical cmy image on the recto side of the substra ...

Wiley-Blackwell2014

Exact Diagonalization of Heisenberg SU(N) Models

Frédéric Mila, Pierre Marcel Nataf

Building on advanced results on permutations, we show that it is possible to construct, for each irreducible representation of SU(N), an orthonormal basis labeled by the set of standard Young tableaux in which the matrix of the Heisenberg SU(N) model (the ...

2014

HDR image compression: a new challenge for objective quality metrics

Touradj Ebrahimi, Philippe Hanhart

High Dynamic Range (HDR) imaging is able to capture a wide range of luminance values, closer to what the human visual system can perceive. It is believed by many that HDR is a technology that will revolutionize TV and cinema industry similar to how color t ...

2014

Reactively sputtered coatings on architectural glazing for coloured active solar thermal façades

Jean-Louis Scartezzini, Andreas Schueler, Martin Joly, Stefan Mertin, Virginie Hody-Le Caër

Covering a standard solar thermal collector with a coloured glazing, which is opaque to the human eye but highly transparent to solar energy, permits a perfect architectural integration of solar panels into glazed building façades. The colours are based on ...

Elsevier2014

Semantic Awareness for Automatic Image Interpretation

Albrecht Johannes Lindner

Finding relations between image semantics and image characteristics is a problem of long standing in computer vision and related fields. Despite persistent efforts and significant advances in the field, today’s computers are still strikingly unable to achi ...

EPFL2013

What is the color of chocolate? - extracting color values of semantic expressions

Sabine Süsstrunk, Albrecht Johannes Lindner

We present a statistical framework to automatically determine an associated color for a given arbitrary semantic expression. The expression can not only be a color name but any word or character string. In addition to the color value, we are also able to c ...

2012

Synthesis of authenticable luminescent color halftone images

Roger Hersch, Romain Rossier

The present invention enables creating authenticable multi-ink luminescent continuous tone color halftone images offering means of verifying their authenticity. The invented luminescent color halftone image synthesizing techniques enable increasing the att ...

2012

Revisiting Radiometric Calibration for Color Computer Vision

Sabine Süsstrunk, Seungryong Kim, Matthew Brown

We present a study of radiometric calibration and the in-camera imaging process through an extensive analysis of more than 10,000 images from over 30 cameras. The goal is to investigate if image values can be transformed to physically meaningful values and ...

2011

Surface Construction by a 2-D Differentiation-Integration Process: A Neurocomputational Model for Perceived Border Ownership, Depth, and Lightness in Kanizsa Figures

Christoph Strecha

Human visual perception is a fundamentally relational process: Lightness perception depends on luminance ratios, and depth perception depends on occlusion (difference of depth) cues. Neurons in low-level visual cortex are sensitive to the difference (but n ...

2010

Exploiting redundancy in color images

Joanna Marguier

The colors in a digital image do not only depend on the scene's reflectances, but also on the lighting conditions and on the characteristics of the imaging device. It is often necessary to separate the influence of these three elements, in particular to se ...

EPFL2010

Repairing Gamut Problems in CIECAM02: A Progress Report

Sabine Süsstrunk

The color-appearance model CIECAM02 has several problems, which can result in mathematical instabilities, due to the relation of the chromatic-adaptation primaries to the spectrum locus and to the presumed physiological cone primaries. To keep a correspond ...

2008

Color matching functions for a perceptually uniform RGB space

Sabine Süsstrunk, Joanna Marguier

We present methods to estimate perceptual uniformity of color spaces and to derive a perceptually uniform RGB space using geometrical criteria defined in a logarithmic opponent color representation. ...

2006