Material Visual Appearance Modeling

An authentic material’s surface reflectance function is a complex function of over 16 physical variables, which are unfeasible both to measure and to mathematically model. The best simplified measurable material texture representation and approximation of this general surface reflectance function is the seven-dimensional bidirectional texture function (BTF). BTF can be simultaneously measured and modeled using state-of-the-art measurement devices and computers and the most advanced mathematical models of visual data. However, such an enormous amount of visual BTF data, measured on the single material sample, inevitably requires state-of-the-art methods for storage, compression, modeling, visualization, and quality verification.

Visual surface textures are very complex mathematical models combining a set (about hundred) of underlying Markov random fields, probabilistic mixtures or sampling-based sub-models. Synthetic model-based textures are very flexible, extremely compressed (hundreds of parameters have to be stored only), they may be evaluated directly in procedural form and can be designed to meet certain constraints or properties, so that they can be used to fill an infinite visual surface texture space without visible discontinuities.