Variables separation of the spectral BRDF for better understanding color variation in special effect pigment coatings

• Published in: Journal of the Optical Society of America A
• Main Authors: Ferrero, Alejandro, Rabal, Ana M., Campos Acosta, Joaquín, Pons Aglio, Alicia, Hernanz, María Luisa
• Format: Article in Journal/Newspaper
• Language: English
• Published: Optical Society of America 2012
• Subjects: Arctic; Martínez
• Online Access: http://hdl.handle.net/10261/65398; https://doi.org/10.1364/JOSAA.29.000842

A type of representation of the spectral bidirectional reflectance distribution function (BRDF) is proposed that distinctly separates the spectral variable (wavelength) from the geometrical variables (spherical coordinates of the irradiation and viewing directions). Principal components analysis (PCA) is used in order to decompose the spectral BRDF in decorrelated spectral components, and the weight that they have at every geometrical configuration of irradiation/viewing is established. This method was applied to the spectral BRDF measurement of aspecial effect pigment sample, and four principal components with relevant variance were identified. These four components are enough to reproduce the great diversity of spectral reflectances observed at different geometrical configurations. Since this representation is able to separate spectral and geometrical variables, it facilitates the interpretation of the color variation of special effect pigments coatings versus the geometrical configuration of irradiation/viewing. © 2012 Optical Society of America. The authors are grateful to Dr. F. M. Martínez-Verdú (Department of Optics, University of Alicante) for providing us with the sample of Colorstream T20-02 WNT Arctic Fire. They are also grateful to “Plan Nacional de Física” for funding this work (FIS2010-19756-E), and to the Junta de Ampliación de Estudios (JAE) Program from Consejo Superior de Investigaciones Científicas (CSIC) for providing us with a researcher in formation. Peer Reviewed