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Quantification and prediction of visually perceived specular gloss at three illumination/viewing geometries / Fereshteh Mirjalili in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 13, N° 2 (03/2016)
[article]
Titre : Quantification and prediction of visually perceived specular gloss at three illumination/viewing geometries Type de document : texte imprimé Auteurs : Fereshteh Mirjalili, Auteur ; Siamak Moradian, Auteur ; Farhad Ameri, Auteur ; Mohammad Amani Tehran, Auteur Année de publication : 2016 Article en page(s) : p. 239-256 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Brillance (optique)
Eclairage
Evaluation visuelle
Mesure
vision des couleursTags : 'Brillant spéculaire' 'Evaluation visuelle' 'Niveau de brillance achromatique' 'Eclairage unidirectionnel' 'Brillance mètre trois angles' Index. décimale : 667.9 Revêtements et enduits Résumé : In the present study, attempts were made to clarify the existence of a correlation between visually perceived and instrumentally measured specular gloss of a series of achromatic samples. To this end, seven achromatic physical scales of specular gloss each consisting of 10 or 11 samples were prepared using lithographically printed black, white, and five in between gray papers. The samples were visually assessed and subsequently quantified in terms of a visually uniform color constant lightness scale, by a panel of 14 observers in an especially designed unidirectional light compartment at three illumination/observation geometries, namely 20°/20°, 60°/60°, and 85°/85°. Four statistical parameters were utilized to determine the correlation between visually perceived and instrumentally measured specular gloss. The results show that the instrumental 60°/60° geometry is capable of efficiently quantifying the equivalent specular gloss as perceived by a human observer. Surprisingly, it was also possible to accurately predict the visually quantified specular gloss both at the 20° and the 85° geometries by the aid of applying special linear relationships derived from the instrumentally measured specular gloss of the 60° geometry. Note de contenu : - EXPERIMENTAL : Preparation of specular gloss scales - Instrumental characterization - Visual assessments
- RESULTS AND DISCUSSION : Correlation between visual results and instrumental measurementsDOI : 10.1007/s11998-015-9756-2 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-015-9756-2.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26109
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 13, N° 2 (03/2016) . - p. 239-256[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 17962 - Périodique Bibliothèque principale Documentaires Disponible Assessment of visibility of facial wrinkle reduction by various types of observers / Joyce H. D. M. Westerink in IFSCC MAGAZINE, Vol. 7, N° 1 (01-02-03/2004)
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Titre : Assessment of visibility of facial wrinkle reduction by various types of observers Type de document : texte imprimé Auteurs : Joyce H. D. M. Westerink, Auteur Année de publication : 2004 Article en page(s) : p. 31-36 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Réduction des rides' 'Douceur de peau' 'Evaluation visuelle' 'Types d'observateur' Index. décimale : 668.5 Parfums et cosmétiques Résumé : The prime objective of many facial wrinkle-reduction treatments is to achieve visible improvement. The visibility of before/after treatment differences is therefore often part of the efficacy assessment. This paper investigates whether the background knowledge of the people acting as observers in such assessments has an impact on the results, e.g., the subjects themselves are familiar with their faces, skin professionals have much experience in judging skin quality, and thus both might be more sensitive to small changes.
In a clinical study, 44 female subjects were regularly treated during a period of 12 weeks with one of three wrinkle-reduction treatments : K, L and M (placebo). Photographs were taken before treatment and after 6 and 12 weeks. Three different types of observers judged the photographs:
- Observer type I : Twenty-four lay observers were given the 0- and 6-week and the 0- and 12-week pairs of photographs of all subjects to indicate the one with the least wrinkles in a two-alternative forced-choice procedure,
- Observer type II : The subjects themselves were given the 0- and 6-week and the 0- and 12-week pairs of their own photographs (eight replications) to indicate the photograph with the least wrinkles (two-alternative forced-choice),
- Observer type III : A trained panel of skin professionals (n = 3) each gave a 9-point Fitzpatrick wrinkle-severity score for all individual 0- and 12-week photographs.
It was found that the lay observers perceived the same differences as the subjects themselves: significant improvements after 12 weeks for treatment K (P < 0.0005 and P = 0.005, respectively). No visible effects were seen for treatments L and M, but, most importantly, a significant difference between treatments K and M (placebo) (P = 0.015 and P = 0.01 for independent observers and the subjects themselves, respectively). The trained panel also identified this difference between K and M (P = 0.013) in favor of K, but here it was due to a significant deterioration over time of the ‘placebo-treated’ wrinkles (M, P = 0.03).
Thus, in conclusion, no indications were found that extra knowledge – in the form of familiarity with the own face or in the form of professional training – results in the identification of more treatments that show significantly visible wrinkle reduction.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10543
in IFSCC MAGAZINE > Vol. 7, N° 1 (01-02-03/2004) . - p. 31-36[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003882 - Périodique Bibliothèque principale Documentaires Disponible Looking into special surface effects : diffuse coarseness and glint impression / Zihao Winston Wang in COLORATION TECHNOLOGY, Vol. 132, N° 2 (04/2016)
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Titre : Looking into special surface effects : diffuse coarseness and glint impression Type de document : texte imprimé Auteurs : Zihao Winston Wang, Auteur ; Ming Ronnier Luo, Auteur Année de publication : 2016 Article en page(s) : p. 153-161 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Granulosité Réflectance 'Techniques psychophysiques' Surface 'Effets spéciaux' 'Perception visuelle' 'Eclairage diffus' unidirectionnel' 'Analyse dimensionnelle Glint' Reflet Index. décimale : 667.3 Teinture et impression des tissus Résumé : Diffuse coarseness (graininess) and glint impression (sparkle) are two aspects of visual perception for special-effect materials, including car finishes, etc. Previous work has shown that these two attributes become apparent when illuminated under two distinct illumination conditions: diffuse and unidirectional illumination respectively. The effect of glint impression has significant dependency on the viewing geometry. In this work, three psychophysical experiments were carried out, including diffuse coarseness assessment, glint impression assessment, and finding dimensions of glint space. In the experiments, one geometry for diffuse coarseness and three geometries for glint impression were designed. The three viewing geometries were designed according to a commercial device, BYK-mac, so that the results were used to test the reliability of instrumental measurements. Based on the conclusions drawn from the psychophysical experiments, a further investigation on glint space was conducted using the multidimensional scaling technique. From the visual results, two dimensions, corresponding to two attributes, were extracted and were validated by the instrumental results. Bidirectional reflectance distribution function data were also adopted from another commercial device, Imaging Sphere from Radiant Vision Systems Inc., USA (originally RadiantZemax Inc.), to predict glint impression. Some promising results were obtained. Note de contenu : - EXPERIMENTAL : Samples - Observers - Viewing conditions - Psychophysical techniques
- RESULTS AND DISCUSSION : Repeatability and reproductibility - Testing the instrument performance - Glint dimensionality analysisDOI : 10.1111/cote.12203 En ligne : https://onlinelibrary.wiley.com/doi/epdf/10.1111/cote.12203 Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=25866
in COLORATION TECHNOLOGY > Vol. 132, N° 2 (04/2016) . - p. 153-161[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18025 - Périodique Bibliothèque principale Documentaires Disponible