Model-based face image coding using spherical harmonics

Model-based image coding technique combines image processing, computer vision and computer graphics techniques to achieve higher coding efficiency. Traditional model-based image coding techniques encode the motion in image sequence as changes of model parameters, thus very low bit rate could be achieved for video coding. In this paper we present a novel method to improve coding efficiency of face images. The key idea is to use spherical harmonic representation of illumination and a generic face geometric model to encode the variation of appearance produced by diffuse reflection. We show that this method improves coding efficiency. This method is complementary to other model-based image coding techniques.