A linear algorithm to estimate the plane of infinity

This paper considers the 3D reconstruction problem from an image sequence taken by a camera with constant internal parameters. Stratified method starts from a projective reconstruction, refines it into affine reconstruction and finally upgrades it to metric reconstruction. It was reported that the most difficult step is to obtain the affine reconstruction, that is, to find the plane at infinity in the projective coordinate frame. In this paper, we give a simple linear solution to estimate the location of infinity plane when the camera´s rotation is small. The developed method depends on the linear relationship among three main diagonal elements of the infinity homography of such two views. Three images are sufficient to give one unique solution, which can be used as the start point of nonlinear constraints. Simulations showed that out algorithm gives very close estimation to the exact location of the plane of infinity.