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1	Color constancy improves for real 3D objects Hedrich, Monika, Bloj, Marina, Ruppertsberg, Alexa I. January 2009 (has links) No / In this study human color constancy was tested for two-dimensional (2D) and three-dimensional (3D) setups with real objects and lights. Four different illuminant changes, a natural selection task and a wide choice of target colors were used. We found that color constancy was better when the target color was learned as a 3D object in a cue-rich 3D scene than in a 2D setup. This improvement was independent of the target color and the illuminant change. We were not able to find any evidence that frequently experienced illuminant changes are better compensated for than unusual ones. Normalizing individual color constancy hit rates by the corresponding color memory hit rates yields a color constancy index, which is indicative of observers¿ true ability to compensate for illuminant changes. Colour constancy 3D Real objects Typical illuminants Atypical illuminants Colour memory Surface matches
2	Basic colour names for 2D samples: Effects of presentation media and illuminants. Hedrich, Monika, Bloj, Marina January 2010 (has links) no / We have previously shown (Bloj et al., 2008; Abstracts Materials & Sensations 2008) that under particular conditions colour memory is independent of presentation media, and of the illuminants under which colours are viewed. In the present study we investigate whether colour naming is also unaffected by these two factors. Forty-eight colour samples from the Natural Colour System (NCS) collection were presented as real paper samples or as accurate computer simulations displayed on a calibrated monitor. The colour swatches could be presented under a daylight illuminant ¿ two intensities, 85 ( D1 ) or 60 cd m)2 ( D2 ) ¿ or a purple illuminant, 45 cd m)2 ( Lily ). The colour samples were shown in arrays of 16 (4 · 4 layout) and the observer s task was to assign one of the eleven basic colour terms to each of the samples. Six observers repeated this colour naming task five times for each presentation medium and illuminant. On average, in 73% of the cases the same colour term was assigned to surface and display colours. This level of agreement was highest for colour samples under daylight (D1-82%, D2-73%) and poor for Lily (65%). Although colour memory is unaffected by the nature of the colour stimulus, here we show that there are limitations to cross-media agreement in colour naming. Colour 2D Colour naming Cross-media comparison Illuminants Stimuli
3	Human colour perception : a psychophysical study of human colour perception for real and computer-simulated two-dimensional and three-dimensional objects Hedrich, Monika January 2009 (has links) No description available. 617.7
4	Human colour perception. A psychophysical study of human colour perception for real and computer-simulated two-dimensional and three-dimensional objects. Hedrich, Monika January 2009 (has links) Pontificia Universidad Católica de Valparaíso Colour constancy Colour memory Colour categories 2D and 3D objects Typical and atypical illuminants Human colour perception Visual perception Colour vision
5	Mesure et Analyse Statistique Tout Temps du Spectre du Rayonnement Solaire / All Weather Solar Spectrum Measurement and Statistical Analysis Tourasse, Guillaume 19 December 2016 (has links) Ce document présente la mise en place d’un système de mesure des éclairements énergétiques spectraux solaires pour tout type de temps, sur 4 plans. Les 4 spectromètres mesurent au total 900 spectres/min et produisent chacun un spectre/min moyen et son écart type. Entre 2014 et 2015, 700 000 spectres ont été enregistrés sur un domaine compris entre 400 et 1000 nm avec un pas ≤1 nm. Un échantillon de 145 000 spectres représentatifs du climat lyonnais a été sélectionné pour une analyse statistique. Pour ce faire, l’échantillon a été réduit par partitionnement à 1175 spectres. Son domaine spectral a été étendu de 280 à 1500 nm à l’aide du RTM SMARTS. Une ACP de cet échantillon extrapolé a permis d’en réduire la description à 3 composantes et ainsi de réviser le modèle des illuminants D de la CIE. Enfin, la relation entre composition spectrale et paramètres environnementaux ou colorimétriques ouvre une voie vers des modèles statistiques de génération de spectres du rayonnement solaire. / This manuscript presents the design and setup of an all-weather spectral irradiance measurement system on 4 planes. The 4 spectrometers measure a total of 900 spectra/min to produce every minute, a mean spectral irradiance and its standard deviation. Between 2014 and 2015, this system recorded 700,000 spectra, for wavelengths ranging between 400 and 1,000 nm with a step ≤1 nm. A sample of 145,000 spectra representative of the Lyon climate was selected for statistical analysis. For this purpose, the sample was reduced in size by partitioning it in 1,175 spectra. Its spectral domain was extended to 280-1,500 nm by extrapolating the spectra with curve fitting using the SMARTS2 RTM. A PCA of the extrapolated sample reduced its description to only 3 components; hence, allowing a revision of the CIE’s illuminant D series. Finally, the relation between spectral power distribution and environmental or colorimetric parameters opens a way towards statistical models for generating solar spectra. Mesure au sol Etalonnage Eclairements énergétiques spectraux Climatologie spectrale Représentativité climatique Partitionnement de données Extrapolation spectrale Analyse en composantes principales Illuminants D Paramètres météorologiques Colorimétrie Modèle statistique Tout temps Ground measurements Calibration Spectral irradiance Spectral Climatology Climatic Representativeness Cluster analysis Spectral extrapolation Principal component analysis D series of illuminants Meteorological parameters Colorimetry Statistical model All weather

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