Using differential constraints to generate a 3D face model from stereo

We propose a way to incorporate a priori information in a 3D stereo reconstruction process from a pair of calibrated face images. A 3D mesh modeling the surface is iteratively deformed in order to minimize an energy function. Differential information about the object shape is used to generate an adaptive mesh that can fulfil the compacity and the accuracy requirements. Moreover in areas where the stereo information is not reliable enough to accurately recover the surface shape, because of inappropriate texture or bad lighting conditions, we incorporate geometric constraints related to the differential properties of the surface, that can be intuitive or refer to predefined geometric properties of the object to be reconstructed. They can be applied to scalar fields, such as curvature values, or structural features, such as crest lines. Therefore, we generate a 3D face model using computer vision techniques that is compact, accurate and consistent with the a priori knowledge about the underlying surface. © 1998 IEEE.