Pose Disambiguation in Uncalibrated Structure from Motion

In this paper we examine the ambiguities between extrinsic and intrinsic parameters in the uncalibrated structure and motion problem. The Jacobian J of the reprojection error is considered, treating each camera separately. Ambiguities correspond to linear dependencies in the column space of J and we thus detect and quantify these by using the condition number of selected combinations of columns of J. When the presence of an ambiguity has been detected, we automatically select a constraint (e.g. constant principal point, or a regularity constraint on the camera motion) that resolves this ambiguity. As a by-product we also obtain a better separation between intrinsic and extrinsic parameters. The proposed method is demonstrated on both synthetic and real data, with good performance.