We present an easy-to-use measurement of BRDF for material appearance of three-dimensional object based on the estimation of surface reflectance properties with 360-degree light probe. Conventional methods of BRDF measurement such as gonio-reflectometry have some problems relating to the size, cost, and difficulty of operation. Appearance from Motion Method proposed by Dong et al. is appropriate to conquer above problems. Their method attempted to estimate the surface reflectance under unknown incident light component. However, a use of multiple unknown parameters causes the loss of convergence, and sometimes sacrifices the accuracy and computational cost. Therefore, we improved their algorithm of Appearance from Motion method by using an omni-directional camera as a light probe. We demonstrate valuable results: Higher reproducibility and lower cost of computation than those of the conventional method.

View full abstract

A visible photo-illumination on the carthamin red pigment solid film was carried out in the study. It was found that the greenish metallic luster of the film was weakened by the photo-illumination and the absorption of the film was also weakened at the same time. Because the deterioration of the carthamin chromophores was induced by the photo-illumination, the absorption in the green light band was probably an important factor of the metallic luster generation.

View full abstract