Derivation of an instrumentally based geometric appearance index for the automotive industry / Fereshteh Mirjalili in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 11, N° 6 (11/2014)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 6 (11/2014) . - p. 853-864 Titre : Derivation of an instrumentally based geometric appearance index for the automotive industry Type de document : texte imprimé Auteurs : Fereshteh Mirjalili, Auteur ; Siamak Moradian, Auteur ; Farhad Ameri, Auteur Année de publication : 2014 Article en page(s) : p. 853-864 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Vernis Brillance (optique) Evaluation visuelle Imagerie (technique) Vernis -- Défauts Index. décimale : 667.9 Revêtements et enduits Résumé : In the present study, attempts were made to develop an index of geometric appearance capable of accurately predicting and quantifying the visually perceived geometric aspects of appearance of achromatic automotive finishes. To this end, three previously prepared individual scales for the three most significant geometric appearance attributes, namely specular gloss, distinctness of image (DOI), and orange peel for each of a series of metallic black, metallic gray, metallic silver, and solid white automotive finishes were utilized. The differences in each attribute were quantified visually by a panel of 16 observers, in terms of a lightness difference of an also previously prepared lightness scale. The innovative use of a common lightness scale showed that there is a surprisingly good correlation between the instrumentally measured specular gloss, DOI, and the LW parameter of the Wave scan instrument and the corresponding visually evaluated equivalents at the four investigated achromatic levels through minimizing observer errors and enhancing accuracy of the perceptibility procedure. These high accuracies made provisions for the implementation of the principle of additivity which led to the derivation of a geometric appearance index (GAI). However, before its derivation, one instrumentally measured parameter was remodeled exponentially to define an innovative parameter chosen to be named "percent absence of orange peel". The proposed GAI illustrates high correlation with visual assessments and is herewith recommended as a stand-alone index for predicting the geometric appearance of automotive finishes. Furthermore, this index together with a chromatic appearance index could form the foundation for deriving a total appearance index for the automotive industry. Note de contenu : - Preparation of appearance attribute scales - Instrumental characterization - The design common lightness scale for visual assessments DOI : 10.1007/s11998-014-9608-5 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-014-9608-5.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22309 [article]

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Effect of color on some geometric attributes of visual appearance of non-effect coatings / Ali Mohammadalizadeh in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 4 (07/2020)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 4 (07/2020) . - p. 949-961 Titre : Effect of color on some geometric attributes of visual appearance of non-effect coatings Type de document : texte imprimé Auteurs : Ali Mohammadalizadeh, Auteur ; Farhad Ameri, Auteur ; Siamak Moradian, Auteur ; Fereshteh Mirjalili, Auteur Année de publication : 2020 Article en page(s) : p. 949-961 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse d'image L'analyse d'image est la reconnaissance des éléments contenus dans l'image. Il ne faut pas confondre analyse (décomposition en éléments) et traitement (action sur les composantes) de l'image. Analyse de variance En statistique, l'analyse de la variance (terme souvent abrégé par le terme anglais ANOVA : ANalysis Of VAriance) est un ensemble de modèles statistiques utilisés pour vérifier si les moyennes des groupes proviennent d'une même population. Les groupes correspondent aux modalités d'une variable qualitative (p. ex. variable : traitement; modalités : programme d'entrainement sportif, suppléments alimentaires ; placebo) et les moyennes sont calculés à partir d'une variable continue (p. ex. gain musculaire). Ce test s'applique lorsque l'on mesure une ou plusieurs variables explicatives catégorielles (appelées alors facteurs de variabilité, leurs différentes modalités étant parfois appelées "niveaux") qui ont de l'influence sur la loi d'une variable continue à expliquer. On parle d'analyse à un facteur lorsque l'analyse porte sur un modèle décrit par un seul facteur de variabilité, d'analyse à deux facteurs ou d'analyse multifactorielle sinon. (Wikipedia) Aspect peau d'orange (peinture) Brillance (optique) Couleur Evaluation visuelle Revêtements Index. décimale : 667.9 Revêtements et enduits Résumé : The aim of the present study was to investigate the effect of color attributes of appearance on the corresponding geometric attributes of appearance of non-effect coatings. Three scales, namely gloss, distinctness of image, and orange peel for three achromatic (black, gray, and white) and four chromatic (red, green, blue, and yellow) basecoats, each at varying levels, were prepared. The gloss and the distinctness of image scales had a sample with a maximum degree of gloss and distinctness of image, respectively, and the orange peel scale had a sample with a minimum degree of orange peel, which was considered to be the standard sample. The visual differences between the standard sample and those remaining in each scale were assessed by a panel of 28 observers using a prepared one-dimensional lightness scale based on the CIELAB and CIEDE2000 color difference equations. The correlations between visual and instrumental measurements of scales were checked, and instrumental performance with respect to visually assessed equivalent differences in gloss, distinctness of image, and orange peel were determined, giving STRESS (standardized residual sum of squares) values = 24.3, 11.6, and 9.7, respectively, in terms of CIELAB. ANOVA together with simple, lasso, and ridge regressions were applied to test the effect of color on the geometric attributes of appearance. The results illustrate that color attributes of appearance have no adverse significant effect on the main geometric attributes of appearance for non-effect coatings. Note de contenu : - EXPERIMENTAL : Preparation of scales - Instrumental measurements - Visual assessments - RESULTS AND DISCUSSION : Intra- and inter-observer variability - Correlation between visual and instrumental differences for each geometric scale - Influence of color on geometric attributes DOI : https://doi.org/10.1007/s11998-019-00315-1 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-019-00315-1.pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34383 [article]

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A new approach to investigate relationships between certain instrumentally measured appearance parameters and their visually perceived equivalents in the automotive industry / Fereshteh Mirjalili in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 11, N° 3 (05/2014)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 3 (05/2014) . - p. 341-350 Titre : A new approach to investigate relationships between certain instrumentally measured appearance parameters and their visually perceived equivalents in the automotive industry Type de document : texte imprimé Auteurs : Fereshteh Mirjalili, Auteur ; Siamak Moradian, Auteur ; Farhad Ameri, Auteur Année de publication : 2014 Article en page(s) : p. 341-350 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Revêtements:Automobiles -- Peinture Brillance (optique) Evaluation visuelle Qualité -- Contrôle Revêtements -- Finition:Peinture -- Finition Index. décimale : 667.9 Revêtements et enduits Résumé : Appearance control has continuously been a major challenge to the automotive industry. In order to implement a consistent control on the appearance of automotive finishes, objective measurement of various appearance attributes such as gloss, distinctness of image, orange peel, etc., is indispensable to the automotive manufacturers. In the present study, attempts were made to find the correlation between visually perceived and instrumentally measured appearance of achromatic automotive finishes. To this end, three physical scales of appearance attributes, namely specular gloss, distinctness of image, and orange peel were prepared using a series of metallic black, metallic gray, metallic silver, and solid white automotive finishes. The samples were visually evaluated by a panel of 16 observers, by utilizing an also prepared lightness scale, in a light cabinet having a 45/0 illumination/observation geometry. The innovative use of a common lightness scale in the present study showed that there is a surprisingly good correlation between instrumentally measured specular gloss, distinctness of image, and Wave scan LW and Wd parameters, and the corresponding visually evaluated data at the four investigated achromatic levels. Note de contenu : - EXPERIMENTAL : Preparation of specimens - Visual assessment experiments - Instrumental measurements - RESULTS AND DISCUSSION : Observer accuracy - Correlation between visual results and instrumental measurements DOI : 10.1007/s11998-013-9544-9 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-013-9544-9.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21453 [article]

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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]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 13, N° 2 (03/2016) . - p. 239-256 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 couleurs Tags : '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 measurements DOI : 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 : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26109 [article]

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