Both of gloss and gloss unevenness are important quality for printing paper. It is difficult to measure gloss unevenness of printing paper with gloss meter. It is assumed that gloss unevenness is caused by surface topography. Thus, measuring surface topography is useful in evaluating gloss unevenness. In this paper, we propose a new method that is composed of a collimator optical system and a telecentric optical system for the low price and quick evaluation. The statistical properties of the surface normal distribution are acquired by the collimator optical system. The spatial frequency property of the unevenness is acquired by the telecentric optical system. To estimate surface topography, we assume that surface topography is expressed as the Perlin noise. The method is proposed to derive the parameters which decide about the Perlin noise model from the measured statistical properties. We estimate the surface topography with this method and verify the validity of the proposed model.
Masanori Maki, Shinichi Inoue, Norimichi Tsumura, "Estimation of Surface Topography using Collimator and Telecentric Optical Systems" in Proc. IS&T 25th Color and Imaging Conf., 2017, pp 147 - 152, https://doi.org/10.2352/ISSN.2169-2629.2017.25.147