Complete Scene Structure from Four Point Correspondences

A new technique is presented for computing 3D scene structure from point and line features in monocular image sequences. Unlike previous methods, the technique guarantees the completeness of the recovered scene, ensuring that every scene feature that is detected in each image is reconstructed. The approach relies on the presence of four or more reference features whose correspondences are known in all the images. Under an orthographic or a ne camera model, the parallax of the reference features provides constraints that simplify the recovery of the rest of the visible scene. An e cient recursive algorithm is described that uses a uni ed framework for point and line features. The algorithm integrates the tasks of feature correspondence and structure recovery, ensuring that all reconstructible features are tracked. In addition, the algorithm is immune to outliers and feature-drift, two weaknesses of existing structure-from-motion techniques. Experimental results are presented for real images.