Oxygenation absorption and light scattering driven facial animation of natural virtual human

摘要

The color of skin is one of the key indicators of bodily change that affect facial expressions. The skin colour tenacity is majorly determined by the light effect and concentration from the chromophores inside skin and haemoglobin oxygenation in the blood. We did an extension work of previous researcher: Donner and Jensen approach to develop a realistic textured 3D facial animation model. Both surface and subsurface effect of light with the skin is considered. Six model parameters are used to control the amount of oxygenation, de-oxygenation, hemoglobin, melanin, oil and blend factor for different types of melanin in the skin in creating a perfect match. Pulse Oximetry and 3D skin analyzer are used to determine the correlation between blood oxygenation and basic natural emotional expressions. The multi-pole method for layered materials is applied to calculate the spectral diffusion profiles of two-layered skin in simulating the subsurface scattering. Torrance-Sparrow bidirectional reflectance distribution function (BRDF) is employed to simulate the light interaction with an oily skin surface stratum. Unity3D is exploited for shading programming to implement advanced real-time rendering. Five basic natural human facial emotive appearance such as angry, happy, neutral, sad and fear are simulated for Asian, European and Middle East male and female. It is suggested that our tailored approach may be helpful for the development of virtual reality and serious games application.