LAUSR

Because coarseness has a remarkable effect on visual appearance, there has been an increasing demand for measuring quantitative coarseness based on an explicit algorithm. In this paper, a novel method for predicting coarseness by measuring only the color and the bidirectional reflectance distribution function (BRDF) is presented. Considering previous studies that require a two-dimensional captured image of a sample that is sensitive to capturing conditions, the proposed method generates images using illumination optical analysis by applying the BRDF, which is insensitive to the capturing conditions. The proposed coarseness prediction workflow was verified based on a comparison of the predicted coarseness values of 56 samples with seven levels of roughness for each of the eight colors and the measured values using BYK-mac, a reliable measurement device for high correlation with visual inspection. The results of the measurement and comparison show that the coarseness orders for each color are similar to each other and that the coarseness variations according to roughness levels are also similar, with a coefficient of determination, R2, of 0.9374.