MEASURING GONIOAPPARENT SAMPLES USING A BIDIRECTIONAL SPECTROMETER; AN SRGB VISUALIZATION (OP11, Pages 60-68)

Many industrial applications within the printing, cosmetic, automotive and clothing sectors deal with gonioapparent targets, whose appearance depends on illumination and viewing angles. The gonioapparent effect of these targets is usually presented with the bidirectional reflectance distribution function (BRDF). In this study, we visualize the BRDF data of a diffraction grating, a CD, a DVD and three different gonioapparent textiles, as sRGB images under D65 illuminant. The study shows that the sRGB images could be used to visually inspect the differences in the sample surface structure and with textiles the colour of threads which compose the sample. This study was aimed to use commonly available samples and shows that their sRGB images could be used even by non-experts to visually compare different structures, colours, orientations and periods of the samples. The results also indicate that the sRGB images could also be used to extract the grating period of the diffractive sample surfaces. Moreover, images of knitted and woven textiles are distinguished.