Model-based corrections of geometric errors in multiangle measurements of gonio-apparent coatings

• Published in: Color research and application Vol. 41; no. 4; pp. 372 - 383
• Main Authors: Imura, Kenji, Teraoka, Yoshitaka
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01.08.2016
• Subjects: geometric errors; gonio-apparent coatings; model function; multiangle measurements
• ISSN: 0361-2317; 1520-6378
• DOI: 10.1002/col.21962

Numerical corrections of colorimetric errors caused by positioning error and irregular geometry in multiangle measurements of gonio‐apparent coatings are presented. These corrections use a model function approximating the gonio‐reflection characteristics of the coating to convert the angular displacement due to those geometric errors to reflectance factor errors to be corrected as well as to estimate the angular displacement conversely from the reflectance factors. The performance of these corrections was evaluated for 11 different gonio‐apparent coatings using a multiangle geometry conforming to ASTM E2539 consisting of eight subgeometries to which artificial displacements were applied so as to present typical positioning errors or irregular geometries. The results show that both corrections significantly reduce the colorimetric errors for all specimens in all subgeometries sensitive to geometric errors. © 2015 Wiley Periodicals, Inc. Col Res Appl, 2015