1. A method, comprising: applying a feature matching technique to a pair of images to determine an initial set of feature correspondences for the pair of images, wherein one or more features of the pair of images are not matched by the feature matching technique and are thus not included in the initial set of feature correspondences; determining additional feature correspondences for the pair of images among the one or more features not included in the initial set of feature correspondences, wherein said determining additional feature correspondences comprises: identifying two or more regions in each of the pair of images, each of the regions potentially mapping to a plane in a 3D space corresponding to the images, and each of the regions including at least one feature in the respective image; identifying matching region pairs between the pair of images; and identifying the additional feature correspondences in the matching region pairs; and storing the initial set of feature correspondences and the additional feature correspondences in a memory for later use.