Estimation of spectral bands of metallic coatings assessed by multi-angle spectrophotometers

摘要

Using three commercial multi-angle spectrophotometers, we have measured the reflectance spectra over catalogues from the automotive industry that contain metal and interference pigments and involve changes in hue and lightness at certain viewing angles. We have used principal-component analysis to determine the spectral distribution of their constituents in order to compare between the basis functions assessed by each instrument and common measurement geometry and to examine differences between multi-angle spectrophotometers. Our results corroborate that at least a minimum of 8 basis vectors are needed to explain 99.99% of the total variance. Comparisons conclude the existence of differences in those vectors associated with interference pigments. Reconstruction of the original reflectance spectra suggest that those detection geometries close to the specular reflection provide the least accurate results.