Face relighting under arbitrary unknown illumination conditions based on estimated light source direction

In this paper, we present a novel method to estimate the light source direction and relight a face texture image of a single 3D model obtained under arbitrary unknown illumination conditions. We create a virtual irradiance sphere to detect the light source direction from a given illuminated texture image using both normal vector mapping and weighted bilinear interpolation. We then create a relighting equation with estimated ambient intensity and diffuse intensity obtained by the least square method. We provide a series of experiments on both light source estimation and relighting to show that our method is effective in restoring the shading and shadows areas of a face texture image. Our approach for face relighting should be used for illuminant invariant face recognition applications.