**Basic equations:**- (Image points (
*u*,*v*), (*u*',*v*') 3D projective point ) **Method 1:**- eliminating
*s*and*s*' giveswith , the

*i*-th*row vector*of . Since the projective coordinates are*defined up to a scale factor*, we can impose the**constraint**: . The**solution**is simply the eigenvector of associated to the smallest eigenvalue. **Method 2:**- a physically more meaningful criterion

Author: **Zhengyou Zhang**

Email: *zzhang@sophia.inria.fr*